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PROJECTS - American Radio History

1. WIRED 60 cycle Wt 5 Ibs 2L 3452 10 BARREL KIT 20 ARREL KIT 20 3 Poly Pak has done Bu uy MINI BLOCK CALCULATOR Stace CAPACITORS KEYBOARDS 100 for 1 98 10 for 1 Unbelievable Worth 60 It s true 20 key 4 func High precision submini tion keyboards at ridicu caps for all applications lous give away Wt 12 ozs Wt 3 oza Cat 2L 3528 Cat No 2L 3524 BARREL KITS ANO C HOOSE THE 1i5Free of material as the BARREL KIT 201 4 7 BARREL KIT 195 BARREL KIT sige bARRECKIT KIT 2186 BARREL KIT 184 evinsicavons Flaten 2 5 saree sim guy 400 Barts p pes Sat MEPS rium BARREL AUT 382 w leads e is E pur 15 for 1 98 Mooues 45 7 75 for 1 98 22 98 10 for 1 98 1 150 for 15 for 1 98 y 5 for uy Hard to find but we got transformers rectifiers di Truthfully we cant test 1 9 100 material user can Test lamp manufacturer V Y millions Lo amp Hi vuiues odea etc for p c work em MM5740 s keyboard n 8 cellation irom factory dumps inventory Worth 1 98 calculator amp V4 and Vg watt 5 Preformed dumped into encoder chips How good dumps 3V 10 mils Fo 694 ea Like crain o wheat driver chips beneath epoxy 10 tol All marked barrele by factoriea 100 they are we don t know 100 metal film resis 100 s of projects red lens Cat No 213526 Cat No 2L 3515 100 5 2L3534 Cat No 2L
2. SCREEN d T mtl E Pt P N ACC CORRECTOR m LENS L SPHERICAL PROJECTION MIRROR Simplified drawing of single color TV projection tube developed by Advent founder Henry Kioss Three tubes one for each primary color merge images on screen almost four by six cet permit viewing in light almost strong enough to read a book ELEMENTARY ELECTRONICS March April 1977 The Advent Model 750 has a price of 2495 It uses a curved screen which measures 6 feet diagonally additional strong appeal Connect your videoplayer into virtually any video projection system and you re off to new heights of pleasure Your favorite recording stars can be taped for audio and video playback Buffs who videotape family and friends via videocameras say that seeing their tapes on a giant screen is frightening in terms of their life size reality Some whose cam era work is less than professional say that seeing their videotapes on a video projection system with all their deficiencies magnified has in spired them to greater care in their photographic efforts Picture Brightness Or the Lack of It While projection TV is enjoy ing a revival and improvements have taken place the concept as noted is not perfected Even manu facturers concede that Although most systems work well they don t generally offer the level of TV pic ture quality we re used to in terms of sharpness for example that regu lar direct vi
3. ELEMENTARY ELECTRONICS March April 1977 M M 9 9 A A MM 4 4 4 4 M E Aa M M MH a i B o A FLICK OF THE SWITCH Fun picture reference of home military Old Radio Treasures of s Sh Fd DON T LOSE OUT Our books are your key VINTAGE RADIO 1887 1929 Pictorial story of pioneer days 1 000 photos 263 pages 10 95 hard cover 8 95 soft 1930 50 Ham professional radio TV electronics 312 pages 10 95 hard cover 8 95 soft RADIO ENCYCLOPEDIA Gernsback s 1927 classic beautifully recreated 175 pages 14 95 hard cover 10 95 soft RADIO COLLECTOR S GUIDE 1921 32 Data book with 50 000 facts on 9 000 models by 1 100 makers 264 pages 6 95 1926 38 RADIO DIAGRAMS Beitman s classic of 600 models 240 pages 7 00 IMMEDIATE DELIVERY SEND TODAY to Vintage Radio Dep t E Box 2045 Palos Verdes Ca 90274 We pay postage Calif residents add 6 Year round Fun Use Quick Wedge to install a bus connect a motor mount a p c board cinch up a connector L They do all that ordinary screwdrivers do PLUS they hold and start the screw QUICK WEDGE Screw holding screwdrivers Unconditionally guaranteed BUY A SET TODAY See your dealer or write to Kedman Company P O Box 25667 Salt Lake City Utah 84125 17 sizes Copyright 1977 CIRCLE 38 ON READER SERVI
4. PHOSPHOR COATED INTERNAL SCREEN RED BLUE OR GREEN ELECTRON BEAM ELECTRON GUN GN F 3 v d four years in tenns of what we as a family save by not going to the movies Some comments on the or der of the above also include the saving of transportation costs to movies Here are some of the appeals of projection TV as heard over a peri od of several months The impact of it does not wear off You get more involved with what s happen ing on the screen You can get away from it all more effectively than you can via regular TV view ing The reality of what s on the screen is greater because people animals and objects are often shown life size The unreality is greater be cause some things are portrayed larger than life size this unreality is a boon to those viewing TV as an escape The emotional impact of giant screen TV is far greater more powerful than regular TV or put another way soap operas come across soapier An appeal in the making is that of using a video projection systein for playing video games It s an alto gether different experience than playing such games through a stand ard TV set the excitement factor is far greater generated in part by the greater distances the playing or moving objects tennis ball hockey puck ete travel and a heightened sense of competition If you are into videotape record ing a video projection system holds IMAGE PROJECTED TO 41 4 x5 2 3
5. 90 OR 270 PTS OUT OF PHASE 7 S LZ amm aa minty 135 OR 225 Aal OUT OF PHASE SE NL ee 180 ic E OUT OF PHASE E screen The intersection of corresponding numbered lines is the position of the electron beam at that instant of time In this case the two sine waves are in phase In the figure below voltage time relationships are different corresponding voltage points are 45 apart Therefore the waveforms are 45 out of phase Two Frequencies Equal NO Frequency Measurement The frequency of an un known sine wave is determined in a manner similar to phase measurement A known frequency is applied to the horizontal plates while an unknown waveform ap pears on the vertical plates The resulting Lissajous figure will reveal the difference in frequency between ELEMENTARY ELECTRONICS March April 1977 picture labeled B The waveform in A can be adjusted by turning the Vert Pos control to bring the waveform to the center of the screen The waveform in B can be adjusted by turning the Hor Pos control the bring the waveform to the center of the screen The two positioning controls above and to either side of the screen are used to center the waveform Suppose the display for two cycles appeared like either one of the pictures below Which controls would you adjust It is evident that some parts of the waveform are being deflected off the screen in both cases The figure on the left has too much
6. NTS Heath GR 2001 DIGITAL SOLID STATE COLOR TV 315 sq in PICTURE ELECTRO LAB As an NTS student you ll acquire the know how that comes with first hand training on NTS profes sional equipment Equipment you ll build and keep Qurcoursesinclude equipment like the NTS Heath GR 2001 computerized color TV 25 diagonal with varactor diode tuning and digital read out channel selection optional programming capa bility and digital clock avail Also pictured above are other units 5 solid state oscilloscope vector monitor scope solid state ster eo AM FM receiver with twin speakers digital multi meter and more It s the kind of better equipment that gets you better equipped for the electronics industry M ttd Simutated TV Reception v pueg A cevevescserse ane eed a awewenwawve i amp 448 8244444 This electronic gear is not only designed for train ing it s field type like you ll meet on the job or when you re making service calls And with NTS easy to read profusely illustrated lessons you learn the theory behind these tools of the trade Choose from 12 NTS courses covering a wide range of fields in electronics each complete with equip ment lessons and manuals to make your training more practical and interesting Compare our training compare our lower tuition We employ no salesmen pay no commissions You receive all home study information by mail only All Kits le
7. SOLD ONLY WHERE YOU SEE THIS SIGN Radio Shaek A TANDY COMPANY FORT WORTH TEXAS 76107 OVER 5000 LOCATIONS IN NINE COUNTRIES Prices may vary at individual stores and dealers Prices and products may vary in Canada CIRCLE 32 ON READER SERVICE COUPON NRI offers you five TV Audio Servicing Courses NRI can train you at home to service TV equipment and audio systems You can choose from 5 courses starting with a 48 lesson basic course up to a Master Color TV Audio Course complete with E designed for learning 25 diago nal solid state color TV and a 4 speaker SQ Quadraphonic Audio System NRI gives you both TV and Audio servicing for hundreds of dollars less than the two courses as offered by another home study school All courses are available with low down payment and convenient monthly payments All courses provide professional tools and Power On equipment along with NRI kits engineered for training With the Master Course for instance you build your own 5 wide band triggered sweep solid state oscilloscope digital color TV pattern generator CMOS digital frequency counter and NRI electronics Discovery Lab Trademark of CBS Inc NRI s complete computer electronics course gives you real digital training Digital electronics is the career area of the future and the best way to learn is with NRI s Complete Computer Elec tronics Course NRI s programmable digital
8. You will learn how to build radios using regular schematics how to wire and solden in a professional manner how to service radios You will work with the standard type of punched metal chassis as well as the latest development of Printed Circuit chassis You will learn the basic principles of radio You will construct study and work with RF and AF amplifiers and oscillators detectors rectifiers test equipment You will learn and practice code using the Progressive Code Oscillator You will learn and practice trouble shooting using the_Progressive Signal Tracer Progressive Signal Injector Pro gressive Dynamic Radio amp Eiectronics Tester Square Wave Generator and the accompany ing instructional material You will receive training for the Novice Technician and General Classes of F C C Radio Amateur Licenses You will buiid Receiver Transmitter Square Wave Generator Code Osciilator Signal Tracer and Signal Injector circuits and learn how to operate them You will receive an excellent background for television Hi Fi and Electronics Absolutely no previous knowledge of radio Or science is required The Edu Kit is the product of many years of teaching and engineering experience The Edu Kit will Provide you with a basic education in Electronics and Radio worth many times the low price you pay The Signal Tracer aione is worth more than the price of the kit THE KIT FOR EVERYONE You do not need the
9. HYPNOTISM MAGIC TRICKS ETC FREE Trick and Magic Catalog 256 Magic amp Fun Box 1936 AV New York NY 10017 MAGNETS MAGNETS All types Specials 20 disc or 10 bar Or 2 stick or 8 assorted magnets 1 00 Magnets Box 182 E Randallstown MD 21133 MISCELLANEOUS SELF CORRECTING TYPEWRITER RIBBON Most exciting needed advance since the typewriter was invented As of this moment every messy smudge smeary typewriter eraser in the world hits the scrap heap for good No more erasing ever Bottom half of miracle ribbon is like magic wand that makes errors disappear before your eyes To make correc tions just back space shift ribbon selector and retype error Presto White ink makes error com pletely invisible Order extra ribbons for friends This is one gift they will love you for 1 ribbon 3 50 2 ribbons 6 00 When ordering name the maker and model of typewriter Order today Cordova Enter prises 156 Shepard Ave Kenmore N Y 14217 ROACHES Killed Fast Safe Guaranteed 7 95 Powhatan Enterprises Box 1896 Tampa FL 33601 MONEYMAKING OPPORTUNITIES STUFF MAIL ENVELOPES 250 00 profit per thousand possible Offer details Stamped self ad dressed envelope Kings B 21487K EE37 Ft Lauder dale FL 33316 HOW to Make Money Writing Short Paragraphs Information Free Barrett Dept C 21 Y 6216 N Clark Chicago 60660 500 00 PROFIT Stuffing 1000 envelop
10. Mostly gq watters 1 to 2 ers 9 PC Use hut he dumped em in bar Type TO 92 TO 18 all 18 etc assorted 2N num uuction sale Prime and barrel ed em Your ad 5 9 tol amp a barrel of 79 a 100 watters reis Preformed ior PC use manufacturers variety of bers unmarked ete ee ae only Long leads vantage Cat No 2L2613 values Cat No 212609 No 2L2608 100 good Mixed values too 2L2605 2N f Cat No 594 Cat No 2L 2603 Untested Cat 212598100 gooc um BARREL KIT 317 BARREL KIT fis BARREL KIT 14 BARREL KIT 12 KRONOS e eepin Jumbo 5 re e Biinking c Beeper MACHINES 40 for 75 for ome ao ae RE 1 98 f 1 98 Untest Amazing includes 55x 1 98 Su good NPN plastic TO220 type 28 to 40 pin devices osc antenna who knows Singles duals variety of Assorted 2N numbers marked interna factory From transistor radio man vatues styles big ones No 2L 2425 Untesteu numbers etc 21 2424 ufacturers 100 2L 2422 jamal ones Cat No 2L 2421 BARREL KIT 4 BARKEL KIT 23 BARREL 2X T 2 BARREL KIT 1 C cat No 2L 3505 A 100 RECTIFIERS 1N4148 914 CSP LINEAR Dit AMPS SN7400 DIP IC S 9 e um c DM IT 100 for gp SWITCHING DIODES Dres 75 for 75 for 1 98 O cit S agADOUTS Kit K 1 98 100 for 1 98 1 1 98 Saul 14 cade E 1N4000 serie May in Bine rampus switching May include 709 s 741 s Pin dips may include gates elude 25 0
11. i ded eS Ee _ ee d ee PS a ee eee muy nd eye cm FM AM a EE n e Minim eremmpet nm nien Pump ipte a Ee UL n Ihe STA 16 offers versatile hi fi at low cost FET IC front end and PLL multiplex for superb FM stereo 3 5 watts per channel minimum RMS at 8 ohms from 30 20 000 Kz with ne more than 0 9 total harmonic distortion Ceramic and magnetic pheno inputs Tape outputs Exclusive Quatravox amp synthesizer And more Only 119 95 Includes custom vinyl vemeer case Ni WOES GET e hes PL PIE PP Li PSTHIT Occrbeatsrcedanse Use your credit card dev at most stores e E d d Lue E ra a 5 ara ae TREBLE Ix Tne STA 21 introduces audiophile controls and circuitry to the economy price range PLL demodulator 7 watts per channel minimum RMS at amp ohms from 20 2 000 Hz with no more than 0 9 total harmontc distortion Loudness tape monitar main remcte speaker switching mono stereo button more Only 159 95 Includes custom vinyl veneer case v QA NOE OR UME JE AK ERM tu fas MHz oedbanige diate rowek The STA 52 combines clean sound and luxurious design PLL demodulator Direct coupled amplifier 12 watts per channel minimum RMS at 8 ohms from 20 20 000 Hz with no more than 0 9 total harmonic distortion Pushbutton loudness tape moniter stereo monc Quatravox synthesizer Much more Only 199 95 Includes handsome walnut veneer case
12. la P E x y y e 1 i F b S t 48 y o p OPNS quU TONS P Photo at left shows placement of parts in author s clock Placement is entirely uncritical and you can use any con venient arrangement depending on the space you have in the case you select Picture above shows the actual module Mod X has six 7 segment LED numerals they all look like eights here since no segments are lit up Connections to the module are made via the 11 terminals holes in the bottom edge of the board plus a few others at the top 59 DoNv r Look Now but there are al most as many CB stations operating above below and in between authorized CB channels as there are on the chan nels The FCC hasn t been happy about this but has been able to do little about it for lack of funds and manpower As a result these channels buzz away with CBers These are among the little known facts about CB The Low Frequencies The CB chan nels start at 26 965 MHz Channel 1 or do they Fact is that if you have a communications receiver you can tune in frequency as low as 26 630 and hear CB communications and they seem to pop up every 5 or 10 kHz right on up the band to Channel 1 This is accomplished several illegal ways by means of sliders VFO s Vari able Frequency Oscillators crystals and PLL modifications Each method is strictly in violation of Part 95 A slider is a modification to a CB rig usually it
13. 11207 Leadership in creative electronics since 1945 HIT CIRCLE 2 ON READER SERVICE COUPON NEWSCAN removal the towers are simply re floated and towed away Future ranges will also be built off shore using the same type of tower and resulting in even greater savings These new training ranges are solar powered The system allows Navy and Air Force pilots to train in air to air combat while dueling in mock dogfights with other pilots who are also flying high performance jet planes The ground in structors monitor the pilots every move while in action and teach advanced tactics The entire mission is recorded and may be replayed to the pilots or instructors at later times for study SELF SUFFICIENCY A higher level of self sufficiency has been opened up for paraplegics quad raplegics and other persons with im paired limbs through the introduciton of a new dictation equipment system The system designated the Sony VR 35 the VR stands for Vocational Re habilitation utilizes a voice activated recording mechanism and is operated By using a magnetic mouth wand a quadraplegic can gain a high level of self sufficiency with a new dictation system from Sony Here Jack Achtenberg a quadraplegic demonstrates his ability to operate the Sony VR 35 to Masaru Ibuka honorary chairman of Sony Corporation by a mouth wand with a magnet at its tip so even if a person has no func tioning
14. 7 95 M C Auto Stereo Service amp Installation 252 p 245 il 5 95 M OSrve Cassette amp Cartridge Tape Players 294 p 196i 6 95 M O Experimenting With Electronic Music 180 p 103 il 495 M OCassette Tape Recorders How Work Care Repair 204 p 4 95 JAcoustic Techniques for Home amp Studio 224 p 168 i 5 95 ig CJPictorial Guide to Tape Recorder Rprs 256 p 320 it 4 95 m JHow to Repair Musical Instrument Amps 288 p 50 il 5 95 E JJap Radio Record Tape Player Srvcg Manual 228p 6 95 Em O Servicing Electronic Organs 196 p 158 il 7 95 E CJTape Recording lor Fun amp Prolit 224 p over 200 il 595 E Im XU Jol L LE Le MARAME E Each vol has complete service data parts lists tull size schematics and all other info needed Each 8 2 11 196 pps n Each only 5 95 unless ked COLOR TV Adm Vol 10 Vol 2 ay 6 95 OGE Vol 1 OVol 2 C Vol 3 O Jap Vol 10 Vol 2 4 95 py C Vol 3 4 95 O Vol 4 C Vol 5 C Magnavox Vol 1 4 95 C Vol gy 2 4 95 CO Voi 3 O Airline C Mot Vol 1 4 95 C Vol 2 C Philo g ORCA Voi 10 Vol 2 O Yol 3 O Vol 4 O Vol 5 O Sears O Serv B Modular Rec r Yol 1 6 95 O Voi 2 4 95 O Syl Vol 10 Vol 2 W ClToshiba O Zenith Vol 1 O Voi 2 DO Vol 3 OVol 4 OBAW TV M Adm 7 95 C GE 7 95 x as 6 95 CMM 4 95 OMot 4 95 8 C Philco 4 95 ORCA 7 95 D Syl 4 95 CI Zenith 7 95 O NO RISK COUPON MAIL ENTIRE AD TAB BOOKS Blue Ridge Summit Pa 17214 Piease send me b
15. and ad ditional points for protection can be added at any time without any changes in the alarm itself This type of instal lation has a distinct advantage over ultrasonic systems which protects only 68 DE EY p UU o He DAY J JN ERA LY Fa OANA v4 FLA L the room in which they are installed Provision has also been made to use normally open switches as desired in addition to the series circuit of conduc tive foil Thus it is possible to add foot operated switches in hallways and door ways and as additional protection This also permits the burglar alarm to be used in an automobile where the open ing of a door which normally activates the dome light switch now also oper ates the alarm Once the alarm is acti vated by opening or closing a circuit it cannot be turned off by just restoring Photograph at left shows completed board with the two ICs Large power transistor at lower left is Q2 which drives alarm speaker Six terminals at right edge of board con nect to speaker foil loop switches Reset switch and power source A Lu oe ML pem A S i Sl Lu CAE 2 PON i dM T De Aet the disturbed circuit to its original condition i e closing the door or win dow A reset switch must be pressed otherwise the alarm will continue to sound Works For Fires Too B F Brain becomes a fire sentry as well simply by buying easily available fire sensors and installing them whereve
16. approximately the amplitude of signals The scope can also be used to measure the phase of two related signals This involves the use of Lissajous figures You will also learn how a scope creates Lissajous figures to determine the frequency of a signal by displaying it in combi nation with a signal of known frequency The Scope Graticule Most scopes are supplied with a circular piece of transparent plastic the same diameter as the face of the CRT screen This graticule has vertical and hori zontal lines drawn on it to form a grid When the graticule is snapped into place in front of the CRT screen it can be used to measure approximately the amplitude of signalis This is done by first pressing or turning the Calibrate control which displays a signal of known amplitude on the screen usually 5 volts or one volt By adjusting the size of the calibrating signal with the vertical amplitude controls you can make the signal fill five or 10 or any other convenient number of gradations on the graticule Then switching off the Calibrate signal and display ing the unknown amplitude signal will permit you to count the number of gradations on the graticule for ready comparison with the Calibrate signal Similarity Among Oscilloscopes The oscilloscope you use may differ in some re spects from the one described here Controls and cir cuits may be identified by different titles and many of the circuits may be designed different
17. equipment from stock 64 fact filled pages loaded with 100 s of highest quality profes sional alarm products technical notes diagrams ONE STOP SUPERMARKET SELECTION INCLUDES ultrasonics radar infrared undercarpet mats magnetic contacts smoke amp heat de tectors Controls Alarms bells sirens mountain west Blarm supply 9 phone dialers lights guard panels Large selection of tools relays wire holdup alarms books Fills need for industry alarm cos businesses homes institutions Order your copy today Outside U S send 1 00 mountain west alarm 4215 n 16th st phoenix az 85016 602 263 8831 CIRCLE 28 ON READER SERVICE COUPON QUIET NEW 40 CHANNEL CB FROM j LA a 3 i LI l Pg gt hia Wi s MESSENGER 4175 e Exclusive Dual Crystal Filtering cuts adjacent channel interference e Exclusive Tapered Automatic Noise Limiter TANL e Switchable noise blanker e LED bar graph meter e PA capability e Crisp clean Johnson sound X JOHNSON E F JOHNSON COMPANY WASECA MINN 56093 In Canada A C Simmonds amp Sons Ltd CIRCLE 33 ON READER SERVICE COUPON 30 ASK HANK HE KNOWS permit that appeared in the July August 76 issue of ELEMENTARY ELETRONICS L R Clementsport Nova Scotia Heck no Shopping Guide Hank where can get a 40468 and 2N3394 transistor J A Peovia IL Here are t
18. for speaker is acoustic batting supplied with the sound insulation in place Some of it must be temporarily removed when assembling the speakers and crossover First step in assembly after identify ing all the components is to wire the crossover on the plate supplied This plate also contains the high frequency control switch After the crossover is wired the speaker connecting leads are installed in the cabinet and the cross over is connected and then installed on the underside of the cabinet Finally the speakers are connected and install T ed Foam tape strips for each speaker opening and the crossover cutout seal the cabinet for acoustic suspension op cration All that s left is to applv the foam grilles and the column is ready for use If you want to blend the color of the grills into your decorating scheme they can be painted with an Tweeter and woofer speaker hook up is quite easy as long as you know how to twist wires and can enamel or lacquer spray paint Speaker Placement There s no spe cific recommendation tor speaker place ment because every listening environ ment is different just as every listener s desired tonal response differs from that of other stereophiles The best way to get the most pleas ing sound quality is to try all the dit ferent placement systems suggested in the Heathkit manual also using the 3 dB control switch for each placement Use whatever final placement sounds
19. hands on experience helps you learn the how as well as the why EL E cu Testing and troubleshooting are an important part of your learning experience Included in your laboratory is a precision multimeter to diagnose electrical and electronic troubles quickly and accurately i aa m m N Wr mar al 1 e La a a igs i i s i a bls a RS E al Modern space age components like this IC integrated circuit are professional quality and can be used again and again in many of your projects Lesson by lesson piece by piece your knowledge grows Prepare now for a rewarding career in Electronics the Science of the Seventies Electronics miracles are changing to day s world with breathtaking speed This growth in electronics technology has generated a need for electronics technicians trained in theory and practice to build the products maintain them and troubleshoot them during the Seventies and beyond Don t just wait for something to hap pen in your present job Get ready now for a career you ll really enjoy with the opportunity for a good income and the chance for advancement Practical experience with experiments Hands on experience helps to rein force basic theory When you learn by doing you discover the how as well as the why You ll find out for yourself the right way as well as the wrong way to use electronic components How to construct your own circuits t
20. live game input while the 6 digit LED display is the game readout It is amazing how one can with a little imagination design a com plete alphabet with only a seven seg ment LED display KIM 1 can then be programmed so that messages flash or scroll across the display right to left or left to right whichever you prefer Only a few of the many games written for KIM 1 are listed here This is just a small selection to give you a feel for the possibilities Many more games such as Star Trek have been written but they require additional memory be yond the standard 1024 bytes provided with KIM Here is a partial list Lunar Lander You steer a landing craft by varying the amount of fuel If you run out of fuel burn too much or do not slow the craft sufficiently burn too little it will crash You can continuously display the altitude and speed of the craft or by pressing the F key you can monitor the remaining SIX DIGIT LED DISPLAY 85989988 ejes T iniri HEXADECIMAL KEYBOARD This block diagram shows how the main elements of the KIM 1 microcomputer work together as well as with additional input and or output devices With basic unit only all input is manual keyboard and the only readout is the six LED numerals ELEMENTARY ELECTRONICS March April 1977 Von i y ia Welcome back to Computer Read out Last time we visited a micro com puter fair and then we looked at
21. quick installation At 11 95 approx its a steal Get one today e B Choice of models to fit most trunk mount an tennas 8 installs quickly easily eps your antenna secure corrosion proof key lock Exclusive turn proof U boit with tock in stud 7 Made in U S A patent pending W See Your Dealer L1 p l p w PING ORATION Pre Great Neck N Y 11021 516 487 0140 CIRCLE 15 ON READER SERVICE COUPON 18 Hey Look Me Over Continued from page 13 Both Experimentor sockets also accept transistors LEDs resistors capacitors pots virtually all types of discrete com ponents as well as lengths of 22 30 solid hookup wire for interconnection with plug in ease Both Experimentor sockets also feature a unique interlock ing system that permits sockets to be snapped together mixed or matched vertically or horizontally to provide opti CIRCLE 48 ON READER SERVICE COUPON mum configurations for almost any type of circuit and instantly disconnected or reconnected without tools to meet re quirements CSC Experimentor sockets are available now from CSC distributors and dealers or directly from CSC s East or West Coast offices For more informa tion contact CSC at 44 Kendall St Box 1942 New Haven CT 06509 Hobby Wrap Too The new BW 630 Hobby Wrap is a revolutionary battery powered tool for wire wrapping 30 AWG wire onto standard DIP
22. seum If you are near there during 76 your travels drop in and see them Shocking Machines Medical ma chines using high voltage heat or radio frequencies are becoming quite popular with radio collectors Alan Douglas of Pocasset MA displayed quite a number of the machines that he has collected at the AWA Confer ence These machines date back to the middle 1800 s Many of the original machines are housed in small wooden suitcases and were designed to give the patient a mild electrical shock Back in the early days of electricity shocks were thought to be beneficial in treat ing many illnesses There was either a hand cranked generator in the suitcase to develop the shocking voltage or a battery vibrator and induction coil were used These machines were of doubtful value in treating patients and eventually the Federal Government passed strict laws concerning the claims advertised by the makers of these small electrical machines In your travels around the country visiting antique shops and junk stores you will find many of these small suitcase sized ma chines priced at 5 00 to 25 00 If your interest leads to collectibles of this sort you should be able to build up a nice collection in a short time Juke Boxes Jumping Another col lectible with definite connections to the radio wireless hobby is the Juke box It wasn t until the tube type audio am plifier was perfected that the juke boxes really became popula
23. turing a retractable 30 by 40 inch curved screen that raises to a height of 64 inches when in use The TV set lens mirror drawer arrange ment is very much like that of Thea tervision described above Brown s Music Store Video Mas ter is a completely self contained portable model weighing 100 pounds Jt uses a TV lens mirror drawer arrangement similar to Thea tervision and Cinema IV but in a smaller housing measuring 25 inches wide and 22 inches deep when not in use The parabolic screen meas ures 32 by 40 inches In operation the set stands 78 inches high It is priced at 1 395 Tandom Model VPS 2 is a two piece ensemble comprised of a re ceiver projector and 36 by 48 inch curved screen at 1 595 The receiv er projector measures about 36 by 15 by 21 inches and uses a three element 14 inch focal length lens Approximate weight is 45 pounds making the rig portable as compar ed with some others Interesting is the following company claim To our knowledge Tandom has the onlv low priced color video projector with variable picture size capability The VPS 2 has a flat field corrected lens system that permits the user to watch on the attractive screen in cluded or project the picture on a flat surface with the same clarity Projection TV Kits While the price tags of complete assembled video projection outfits range from 995 in the Sega Muntz line on up the buff or experimenter on a budget ca
24. worked with the different kits the Signal Tracer works fine Also like to fet you know that I feel proud of becoming a member of your Radio TV Club Robert L Shuff 1534 Monroe Ave Huntington Ww va ThouEht would drop you a few lines to say that re ceived my Edu Kit and was really amazed that such a bargain can be had at such a low price have already started re pairing radios and phonographs My friends were really surprised to see me get into the swing of it so quickly The Trouble shooting Tester that comes witb the Kit is really swell and finds the trouble if there js any to be found sive Edu Kits Inc 1189 Broadway Dept 583DJ Hewlett N Y 11557 Please rush me free literature describing the Progressive Radio TV Course with Edu Kits No Salesman will call Hewlett N Y 11557 e e X M o G ee A o CONES G 8 ee ee AX uA AA 8 um 11 Two wa impr ovement Ps itt X mt Sar Co Has your CB ever let you down Right when you needed it the most t could be that good deal antenna Or the lightweigat mike that came with the set To get the most out of your 2B switch to Turner at both ends Try a Turner amplified mike You ll find out how much talk power your set can really deliver For full range when you need it Make sure your antenna is dependable Step up to a Turner Turner
25. you can also repeat certain pas sages at will Connect one of the KIM 1 application connector pins to an ampli fier to hear the song play Electronic Organ Each key on the built in keyboard corresponds now to a specific note You play the keyboard like an organ Program changes make it sound like different instruments This is a modification of the previous pro gram Reaction Time Tester A random 4 digit number appears for two seconds on the display then it disappears You then reenter the same number as quickly as possible The 2 right most digits in dicate how many tenths of a second it took you to reenter the number If you make a mistake or take more than 10 seconds FF will appear A variation of this program indicates in 1 100 of a second how long it took you to press a key after a number flashed randomly on the display Hunt the Wumpus Hunt the mythi cal Wumpus through a maze of caves connected via tunnels The danger con sists of bottomless pits bats which can carry you off to a random location and the Wumpus which can eat you Messages appear on the display giving you hints about your situation To catch and to domesticate the Wumpus you throw a sleeping gas canister at his suspected habitat by pressing the PC key The game ends when message You got a hug from Wumpus or You Lose scrolls through the LED display A nice feature of all these games is that a slight reprogramming will com ple
26. 1 the frequency of the input signal If the input frequency is 12 000 cps the sweep fre quency must be 4 000 cps for a three cycle scope pre sentation For two cycles the sweep frequency must be set at 6 000 cps If a single cycle is desired the setting is the same as the input frequency i e 12 000 cps The sawtooth frequency is selected by settings on the Coarse Freq and Vernier controls on the front Sawtooth Sweep for Display CYCLE 2 CYCLES 3 CYCLES I t I 1 WAVE FORM l i l I I l l 1 i i 1 t Li SAW TOOTH panel If the exact frequency number is not found on the coarse frequency markings set the coarse control 84 to the closest number and adjust the vernier control for a stationary pattern on the screen The ratio of waveform to sawtooth frequencies should be such that it is one the order of 1 1 2 1 3 1 4 1 etc When the ratio leaves a quotient that is not a whole number 3 2 for example the display will be a pattern continuously moving across the screen If the pattern appears to be incorrect adjust the proper control Coarse or Vernier Sawtooth Sweep Too Small HORIZONTAL SWEEP QUESTION Q2 Why is there only one sawtooth cycle in each example in the drawing preceding the last one ANSWER A There can be only one sawtooth wave per sweep of the scope regardless of the number of waveform cycles The sawtooth will move the electron beam h
27. 100 il 4 95 di c peepee epee ola n O Modem Electronics Math 686p 424il 9 95 JMaster Hdbk of 1001 Prac Electr Circ 602p 1250 il 9 95 Olmpedance 196 p 90 il 5 95 intro to Medical Electronics 2nd ed 320 p 126 Il 7 95 C Computer Programming Handbook 518p 11441 8 95 D Computer Technician s Handbook 480 p over 400 il 8 95 C Microelectronics 266 p 228 i 5 95 C Basic Digital Electronics 219 p 117 il 4 95 O Switching Regulators Powe Supplies 252 p 128 il 6 95 CJ Adv Appl for Pocket Calculators 304 p 275 il 5 95 Q Tower s Intern Transistor Selector 140p 7 10 4 95 DEtectr Conversions Symbois Formulas 224 p 252 il 4 95 OlEffective T shooting with EVM Scope 238 p 185 il 5 95 C Getting the Most Out ol Electronic Culculators 204 p 28i1 4 95 CJAviation Electronics Handbook 406 p 227 il 8 95 JHow to Test Almost Everything Electr 150 p 144 il 3 95 O Digital ogic Electronics Handbook 308 p 226 il 6 95 C Modern va Me dia of Linear IC s 276 p 301 il 9 95 CJ10 Minuts Test Tech For PC Svcg 216 p 114 il 4 95 CJElectr Unraveled New Commonsense Approach 228 p 5 95 C How To Tshoot Repair Electr Test Egpt 252 p 143 il 5 95 C Understanding Using the Oscilloscope 272 p 170 il 5 95 O Industrial Electr Principles amp Practice 416 p 380 il 8 95 ODictlonary of Electronics 420 p 487 il 4 95 pr II U Color TV Trouble Factbk Probs Sols 3
28. 140 p 122 il 3 95 g O Basic Electricity Beginning Electronics 252 p 191 il 5 95 g C Radio Contro tor Models 350 p 417 il 6 95 E CIMOSFET Circuits Guidebook 196 p 104 il 4 95 M CJ prac Circuit Design for the Experimenter 196p 119i 4 95 WI C 111 Digital amp Linear IC Projects 210 p 275 il 5 95 M Radio Astronomy for the Amateur 252 p 96 il 595 M C Build It Book ol Mini Test Meas Instr 238 p 151 il 4 95 ORF Olgital Test Ta You Can Build 252 p 217 il 5 95 H JMIniature Projects For Electr Hobbyists 168 p 77 il 3 95 T OC Practical Triac SCR Projs For The Exp 192 p 146 il 4 95 u ClIntegrated Circuits Guidebook 196 p 119 il 5 95 E O Solid State Circuits Guidebook 252 p 227 ii 5 95 E O Electronics For Shutterbugs 204 p 109 il 5 95 E O Prac Test Instruments You Can Build 204 p 157 il 495 B O How to Build Solid State Audio Circuits 320 p 190 i 5 95 BM JRadio Electronics Hobby Projects 192 p 214 il 495 BM O Handbook of IC Crreuit Projects 224 p 136 il 495 M C Solid State Projs for the Experimenter 224 p 228i 4 95 M C Electronic Experimenter s Guidebook 182 p 86 il 4 95 CJ 125 One Transistor Projects 192 p 125 il 4 95 Al 164 Hobby Projects for Home amp Car 192 g 159 il 4 95 u Electronic Music Circuit Guidebook 224 p 180 il 6 95 E CQA A About Tape Recording 264 p 102 il 5 95 E O Handbook of Multichannel Recording 322 p 196 il
29. 3401 Cet No 2L 3414 tors Long leads 2L 3413 Cat No 2L3369 BARREL KIT 159 25 for SWITCHES BARREL KIT 158 6 Yes MAGNIFIED MAN 3 s V R s bar switches TV mikens ex the pound cess Dpdt 6pdt etc Brund new Cat No 2L3150 BARREL KIT 7138 PANEL SWITCHES 30 fer HA of clock chip alarm culen dar beepers who knows factory over run NO PiCKEE Mixed in bar reis Cat No 2L 3324 nll mixed Cas No 2L 3308 BARREL KIT 133 BARREL KIT 131 60 for 1 9 809A cicernos C magnifier Factory discon tors asst tinued line 100 mate rial Cat No 24 3325 1 oz BARREL KIT 134 CALCULATOR CHIPS 15 for Ye T NN 143 SISTORS ae z 15 for 1 98 1 000 000 RGA phono pigs ik 1 98 lt x 1 98 m mr thrown in bar 30 for 1 98 Miniature transformer back for this one You hi fi ers 209 material TO 92 Did you hear of OAK An Tha qo Me capt test Smi DIAS ac ied prime top again Asst outputs inter know wut they are factory discontinued lines other eqpt maker barrelled National type Can The famous CD4000 series grade asst values volt stage and audio Only 1 1004 material 2L 3293 pnp s mixed with npns aj types of rotaries elec MM5736 38 etc ue How good Who knows Miei a ON sq Wt 2 ibs 2L 3294 2N4400 1 2 3 4 2L 3290 tric slides ete 2L 32GB tested
30. 548 DV Seattle WA 98111 DO IT YOURSELF REPAIR YOUR COLOR or B amp W TV Anyone can New Easy method Information free Research Publications Box 517 B BREA CA 9262 STOP PAYING EXPENSIVE TV REPAIRS Do It Yourself Anyone can new easy method Details free Publications Box 517 D Brea CA 92621 TAPE SLIDE SYNCHRONIZER lap dissolve mul tiprojector plans 5 50 Audiovisual catalog free Millers Sountage 1896 Maywood S Euclid OH 44121 o EDUCATION amp INSTRUCTION USED Courses Books List 156 Smith s 124 Mari borough Salem MA 01970 UNIVERSITY DEGREES BY MAIL Bachelors Masters Ph D Free revealing deta Counselling es 1425 EE 317 Tustin CA 92689 LEARN Recreational Vehicle Repair Free Infor mation RV Training Dept DP3 5015 N Darfield Covina CA 91724 LINEAR AMPLIFIER 2 30 MHz 140 watt mobile Construction plans 3 00 IGOR Box 5516 GC Walnut Creek CA 94596 THERE IS NO CHARGE FOR THE ZIP CODE PLEASE USE IT IN YOUR CLASSIFIED AD A y Poly Pak EXCLUSIVE 100 S OF BARRELS PURCHASED For the res anywhere Poly Pak merchandisers introduce a new way in buying the economical way Raw stock from the barrel Remember the good ole days They re back again The same way merchandisers 5 runs in barrels the same type BARREL kit 200 IM BARRE
31. B F Brain Continued from page 70 j more but the protection they provide for your house is a small price to pay If you prefer to construct your B F Brain with an AC power supply you may use the power supply circuit we show The transformer should be rated at 18 volts RMS center tapped 2 am peres or more Use a filter capacitor at least as large as that shown Smaller values will re sult in excessive AC ripple on the 12 volt DC line If an AC operated supply is used be certain the no load output voltage of the supply does not exceed 15 volts because the CD4001 integrated circuit may be damaged if fed from a source of power greater than 15 volts Use It In Your Auto Also shown are the proper connections for using B F Here s the way the parts are located on the printed circuit board No heat sink is needed or the big transistor Use an IC socket for 1C2 88 ee Brain in your automobile Terminal L loop is shorted to terminal G ground and a wire from the dome light is connected to terminal C close When installing the alarm in an auto Continued on page 90 Looks like a conservative TV station ELEMENTARY ELECTRONICS March April 1977 Tangent Points TOP TANGENCY TOP TANGENCY SIDE TANGENC Y SIDE TANGENCY A the two The reference frequency could be taken from a calibrated signal generator or from the 60 cycle AC supply which is available on the front panel of mos
32. B amp K 2040 CB Signal Generator its that good The 2040 measures 17 9 in wide x 7 25 in high x 10 6 in deep Weight is 17 25 Ibs It is strictly 105 130 VAC powered there s no option for 13 8 VDC Priced at 475 the generator is supplied with an extensive instruction manual covering CB receiver tests For a complete transceiver test the 2040 is used with a B amp K model 1040 CB ServiceMaster and scope All connec tion cables are optional you provide your own For additional information circle number 75 on Reader Service coupon What We Said Before In our review of the B amp K model 1040 Servicemaster in our January February 1977 issue we wrote We expect B amp K to be coming out soon with companion units for the 1040 Servicemaster They came out a lot sooner than we thought anybody could so we were wrong So to correct a wrong we reviewed the R amp K 2040 above Also the start of the fourth paragraph from the end of the 1040 review we started off with With two minor exceptions This should be stricken from the text and the sentence begins with the word The Sorry about the hasty editing ELEMENTARY ELECTRONICS March April 1977 e e checks out the B amp K 2040 CB SERVICEMASTER One instrument replaces a benchful of test gear for fast transceiver testing and alignment If you ve ever paid hard cash for a CB transceiver checkout or even ac cepted a freebie at a so called
33. BC Reno Nevada 89503 10 000 GUARANTEED OR OWE ME NOTHING No competition 1000 per hour possible Details Free dorm Dept G P O Box 11065 Orlando FL 32803 800 MONTHLY Possible stuffing envelopes Stai immediately Detaiis 1 00 refundab e Elamco B1337 C12 Waldo AR 71770 SELL Books by mail SASE for complete details sae J Box 11766 IO 14 Winston Salem N C 27106 HOW TO RECRUIT Commission Salespeople Free details Success Publications 35 Interlachen Place Excelsior MN 55331 MAKE 200 weekly with unique mailing program keep all of it Guaranteed details free Sales Ex chonee Dept 90 2418 Belgrade Ct Augusta GA 30 06 MAKE 1000 per month mailing letters Fier do tails Tate Box 443 DP Morehead City NC 285957 EARN IMMEDIATELY Stuffing envelopes 300 00 thousand possible FREE SUPPLIES Send stamped envelope Bill Harasymchuk General Delivery Nel son B C Canada VIL 5P3 BIG PROFITS in becoming a supplier to major industry through electro plating small parts and metalizing non metallics Write for free particuars 0026 Room MC 107 GD 1512 Jarvis Chicago IL 60626 10 000 YEARLY doing nothing 15 000 guaran teed Free details PH RRI Inc Box 6061 OH Knox ville TN 37917 2 600 00 PROFIT monthly stuffing envelopes at heme Send self addressed stamped envelope to Chamico Industries P O Box 11762 Dept 201 Pittsburgh PA 15228 DIFFER
34. CB Clinic you know that what you gener ally get is a check of the transmitter s power output the transmitters output frequency on one or more channels and possibly some sort of check of the trans mitter s maximum percentage of modu lation What you rarely if ever get in a ceiver section but you can t work sig nals you don t receive can you The reason few CB checkouts include re ceiver tests is simple the required sig nal generator s often cost upwards of 1200 a steep price for the average service shop But now there s a signal generator available specifically designed for lab grade CB test and repair and its 475 price is low enough to permit its use transceiver checkout is a test of the re in most shops and service stations MODULATION NW m DELTA TUNE SECTION SELECTOR RF SECTION A o B amp K 2040 CB Signal Generator front panel is divided into three sections 40 channel selector is one knob in center section RF controls and meter are all in right section For further information circle no 75 on Reader Service Coupon Re OUTPUT METER AF LEVEL Dl i 455 KHZ RF LEVEL ADJUST Output meter scale and attenuator are calibrated directly in output voltage and decibels RF output control per mits continuous variation from 1 to 100 000 microvolts OUTPUT RF OUT ATTENUATOR ELEMENTARY ELECTRONICS March April 1977 Within months you re certain to f
35. CB and TV servicing 337 Pace communications equipment covers 2 way radios for business industrial and CB operations Marine radiotelephones and scanning receivers are also in this 18 p book 338 Break Break a booklet which came into existence at ths request of hundreds of CBers con tains real life stories of incidents taking place on America s highways and byways Compiled by the Shakespeare Company it is available on a first come first Serve basis ELECTRONICS HOBBYIST 342 Royce Electronics new full color catalog up dates information on their CB transceivers base mobile handheid It also describes new product lines CB antennas and a VHF marine radiotele phone 344 For a packetful of material send for SBE s material on UHF and VHF scanners CB mobile transceivers walkie talkies slow scan TV systems marine radios two way radios and accessories 345 For CBers from Hy Gain Electronics Corp there is a 50 page 4 color catalog base mobile and marine transceivers antennas and accessories Colorful literature illustrating two models of moni tor scanners is also available 350 Send for the free NR McGraw Hill 100 page color catalog detailing over 15 electronics courses Courses cover TV audio servicing industrial and digital computer electronics CB communications servicing among others G I Bill approved courses are sold by mail 352 Send for the free descriptive bulletin from Finney C
36. Cat No 213258 Cat No 2L 3257 Cat No 2L BARREL KIT 12 BARREL KIT 127 BARREL KIT 126 BARREL KIT 119 A BARKEL KIT 118 BARREL KIT 7115 BARREL KIT 112 MINI DIP ICS AXIAL ELECTROS UPRIGHT ELECTROS PRECISION an MINI SCRS MOLEX 100 950006 MICRO MINI LEDS g a RESISTORS i Of 1 98 SOCKETS good 40 for Large mfgr dumped 100 s o 1 98 100 for 1 98 xseLiEvanle 0 92 Cat Nos 1 98 Ibs into barrels Includes 1 98 e PREFORMED Designed for Plastic SCRS in barrels 1 98 2L3144 All the tiny leds axial up T41s LM 380 8 703 567 Asst capacities and imf to 300mf m ph uie printed circuit work 1 4 rite from factory Includes Caleulator maker dump We right of Monsanto Litronix 555 558 but who knows voltages Cat No 2L 3227 of Yo EN irte le edili w Marked values 1 and al voltages up thru 200 ut a zillion of em Used variety of colors Yield W ib 2L3245 n good 2L3 2 values 2 ozs 2L 3205 prv 2L 3135 for IC sockets etc 50 or better 213139 BARREL KIT 7109 BARREL KIT TERMINAL STRIPS WY BARREL KIT 104 SLIDE VOLUME RESISTOR SPECIAL BARREL KIT 293 i101 HALF WATTERS BARREL KIT 99 BARREL KIT 92 PHOTO ELECTRIC X 3 AMP EPOXY SQ cannes for _ CELLS RECTIFIERS SUntested SILVER MICAS Pa r 100 for 1 98 amp Controis Tt 200 for m Of 1 98 200 for 1 98 100 f 1 98 Wide asst of terminal strip 10 for 1
37. How To Make Your Own Built in Furniture 336 p 758 il 5 95 C Homeowner s Handy Do t Manual 280 p 84 il 7 95 C Building Model Ships From Scratch 378 p 84 il 7 95 L Homeowner s Guide to Saving Energy 196 p 18311 5 95 O Customizing Your Van 192 p 150 il 3 95 OThe Woodworker s Bible 434p 1151 5 95 CJ00g Owner s Medical Manual 252p 23711 5 95 C How to Train a Watchdog 224p 45 i 5 95 O Motorcycle Repair Handbook 392 p 260 i 6 95 CO Step By Step Guide Carburetor Tuneup Overhaul 224 p 4 95 C Complete Hdbk ol Model Railroading 350 p 238 il 6 95 C Homeowner s Guide To Solar Heating Cooling 196 p 4 95 CJDo It Yourselter s Guide Home Plan Constr 238 p 4 95 C Step By Step Guide to Brake Servicing 238 p 248 il 4 95 C Step By Step Guide Chrysler Eng Maint Rpr 256 p 5 95 O Subcontract Your House Bldg Remodel 196 p 63 il 4 95 CJ Auto Electronics Simplified 256 p 202 il 5 95 O The Compiete Auto Electric Handbook 210 p 139 il 5 95 C Concrete amp Masonry 392 p 213 il 5 95 O Practical Home Constr Carpentry Hdbk 448 p 180 i 5 95 C How to Repair Diesel Engines 308 p 237 il 5 95 C Central Heating Air Cond Repair Guide 320 p 285 il 6 95 C Small Appliance Repair Guide Vol 2 210 p 119il 4 95 DElect Wiring Lighting For Home Ottfice 204 p 155 il 4 95 C How to Repair Smali Gasoline Engines 2nd Ed 392 p 6 95 C How to Repair Home Auto Air Cond 208 p over
38. LOCK Continued from page 16 communications the crowded frequency spectrum the special aerodynamic anten nas the multipath signals the require ments for reliability all are explained thoroughly Another section a guide through the intricacies of autopilots tells all about gyros servos Servoamplifiers sensors and actuators and shows how these and other systems and components are interrelated Airborne radar its types limitations uses and circuits are fully de tailed Accuracy search radar height find ing and navigation are covered in depth along with radar receivers displays and transmitters Published by Tab Books Blue Ridge Summit PA 17214 E PROTECT YOUR ANTENNA 3a o tenna loc it tenna loc is the first really positive protection designed to keep your antenna intact and in place year round Yes you may remove it for car wash or long term storage but there s no need to every time you park It works like a charm in all kinds of weather and keeps on working for years tenna lo features a turn proof locking stud integrated into a Specially notched U bolt with a 5 tumbler corrosion proof key lock We also give you a heavy duty mounting bracket k a 4 er t A product of VERNI d a ON C2C CONSUMER PRODUCTS DiV S O Lake Success Park Coltgsmuniy L and an electro polished Stainless steel replacement Cup where needed for easy
39. Libertad is tied to the far right and R Euzkadi is a liberal Catholic organization not to be confused with the far left ETA Basque guerillas the two stations have striking similarities Both at one time had ties to the CIA both had even stronger ties to wholly European oper ation something one would not expect to find in Latin America and both sta tions mainained regular schedules clear ly indicating they operated with govern ment Venezuelan consent Before it closed down in 1968 R Libertad had been completely taken over by a right wing Soviet organization known as NTS which maintained headquarters at Paris operated its own Radio Free Russia transmitters in West Germany and solicited reports and letters to a Rotterdam Nether lands post office box The Basque government in exile was organized during World War II with the help of the OSS the CIA s prede cessor and other western intelligence agencies including the Free French Army At that time according to recent Continued on page 90 ELEMENTARY ELECTRONICS March April 1977 ding a ZUEL Tips for the beginner DXer as well as special notes for old hands looking for new catches on medium wave 60 and 49 meter bands _ Columbia and Venezuela two Span ish speaking nations that cover all of South America s Caribbean coast domi nate the popular 60 meter shortwave band 60M is popular with DXers be cause it is seldom used by th
40. MHz Cat No 035103 BAX 1 Broadband Amp 20 Hz to 150 MHz Cat No 035107 4 50 ea 4 50 ea 4 75 ea and postage inside U S Canada and Mexico only will De prepaid by international Prices quoted for US Canada and Mexico orders only Orders for shipment to other countries will be quoted on re quest Price subject to change Address orders to M S Dept PO Box 32497 Oklahoma City Oklanoma 73132 WRITE FOR BROCHURE International Crystal Mfg Co Inc 10 North Lee Oklahoma City Oklahoma 73102 CIRCLE 9 ON READER SERVICE COUPON 20 system of a size such that a variety of instruments can be incorporated within the chamber to study surfaces over extended time periods Dr Thompson sees the vacuum chamber as an important means of forming and studying super thin layers of material layers perhaps only one atomic layer thick Such layers may be useful in the development of future computer components and have become increasingly important as the size of electronic circuitry for computers has become smaller It is important to preserve thin layers over extended per iods to observe any changes that may ELEMENTARY ELECTRONICS March April 1977 AMAZING amp HARD TO FIND SCIENCE BUYS 8 ALTERNATE ENERGY SPACE AGE HOBBIES SUPER POWER FOR ANY AM RADIO 3 SAVE 50 8 x 20 MONOCULAR NASA CHOSEN FOR APOLLO SOYUZ No 1556 EK 9 ax8 4 47 5 oz 99 95 Ppd lm ree ee PRO ELECTR
41. MHz instead of kHz J J Gloversville NY It s easy really Just divide kHz by 1000 to get to MHz or multiply MHz by 1000 to get kHz For example 1 MHz 1000 kHz 10 MHz 10 000 kHz 30 MHz 30 000 kHz 21 75 MHz 21 750 kHz Just examine the examples given and you ll have no trouble doing it yourself Slinky Boinger l noticed that in your May June 1976 issue of ELEMENTARY ELECTRONICS you published an article on the use of a Slinky toy as an antenna You may not have known that we manu facture the Slinkv Dipole Antenna for use as either a transmitting or receiving an tenna We use special oversize coils made especially for us but they resemble the toy coils Our coils however have over 335 Continued on page 29 WRAP TTTTT OK MACHINE amp TOOL CORPORATION ELEMENTARY ELECTRONICS March April 197 3455 CONNER STREET BRONX NEW YORK N Y 10475 U B A PHONE 212 994 8600 TELEX 125091 TELEX 232395 yiker 18 ON READER SERVICE COUPON 27 VAL P IHE M EICO 388 COLOR BAR GENERATOR Pocket size battery operated with LED Indi cator MOS LSI IC provides 9 digitally con trolled stable patterns Crystal controlled chroma and timing oscillators Simply con nects to TV s VHF antenna terminals Wired 89 95 EICO 390 FUNCTION SWEEP GENERATOR Outstanding features include Sine Square Triangle Waveforms 2 Hz to 200 KHz fre
42. aviation program package retail price is 44 95 and the PCIOO printer unit is 295 00 The 14 V DC adapter charger is 12 95 If you d like more infor mation write to Texas Intsrument In corporated P O Box 5012 M S 308EE Dallas TX 75222 Attn SR 52AV Good flying WATER TOWER Technology developed by industry for offshore oil drilling was used to signifi cantly reduce the costs of our Air Force fighter pilot training program Known as Air Combat Maneuvering Instrumen tation the system includes five ocean towers where electronic equipment is mounted to track planes as they fly over the Gulf of Mexico near Tyndall Air Force Base in Florida The 200 foot high towers will be built by Bethlehem Steel for Cubic Cor poration which is a prime contractor for the system Use of the oil drilling towers for an electronic application was Continued on page 24 Hi Pop Mom s still talking to vou down at the office ELEMENTARY ELECTRONICS March April 1977 Occur in a layer s electronic properties In a narmal vacuum system Dr Thompson said this surface layer doesn t stay the same long enough for us to get a good analysis of it We needed something in which we could do experiments over a period of time like two or three days then preserve the surface and analyze it again a month later Although the chamber runs at very low temperatures it contains within it an evaporator hot enough to melt and
43. be wired directly to the computer with cables or you can use the new KIM 4 Motherboard The Motherboard is actually a kind of frame with plug in jacks that allows up to 58 000 memory locations to be added to your KIM 1 Both the KIM 2 and KIM 3 have all the built in control circuitry needed to let them converse with the main com puter without losing any bits Further each board has four little switches that you set to specify the beginning and end of the memory on that board For example setting the switches to 0001 causes the memory address of KIM 2 to run from 2000 to 2FFF which cov ers 4096 memory locations So if you want to talk to that KIM 2 board through your KIM 1 you use any memory location between 2000 and 2FFF The users manual for these memory expansion boards has a test program that can be run to check out their operation The memory will first fill all the memory locations with Os then read back the memory contents to see if Os are really there It then uses Is and so forth until all digits and all memory slots are checked If any mem ory location fails to properly store a 1977 digit the address of the defective mem ory cell is written out to the display or to your teletype terminal Memory Make up The make up structure of the memory expansion boards is simple but interesting The boards are composed of small integrated circuit modules called 2102 static RAMs Each RAM holds 1024 loca tions of one
44. big a picture do you ge from a video projection system A perusal of specs of the 30 compa nies shows screen sizes ranging from 24 bv 32 inches for the self contain ed one unit Sony Model KP 4000 at 2 495 to 75 by 100 inches for Pro jection Systems Inc s Cinevision consisting of TV projector and screen priced at 4 995 Fifteen companies show units with 32 by 40 inch screens By and large video projection sys tems are ungainly klutzy and oversized compared with regular TV sets They require a lot of room for optimum enjoyment In watch ing the popular Advent VideoBeam system for example vou d want to be at least 10 feet from the screen try that in your conventionally fur nished 12 by 15 foot living room and youll see 3t could be a problem However some svstems can be used in smaller spaces Television Projec tion Systems Tele Pro Sys for ex ample can he used in a room as small as 7 feet wide by 11 feet deep the company claims We suggest that in evaluating your purchase that you bring along a drawing of the room iw w which youd use a Many Srofachiaft setups tnbludlings litze screen system by Television Projection Sys tems use TV set and home movie screen ELEMENTARY ELEC RONICS March April 1977 sD e0 E 30777 AJY SSe RAEN Lad 60 fs oa 135 0 Q0D O00 00 ui t FIG Be BAL asce N iC FN et rm OELILIPM i EE EN Mi 3
45. bit cach so to store 1024 bytes with 8 bits per byte you must have 8 of these RAMs in parallel one RAM for each of the 8 data lines The data from KIM 1 first enters a buffer on the KIM 2 or KIM 3 board where it sits waiting to be clocked into the RAMs To tell the RAMs which cell should hold each 8 bit data word there is a 16 bit address word The first three bits of this address word tell which board is being called you can have several boards Another three bits are used to specify the RAMs on the board The last ten bits are used to specify one of the 1024 locations in the RAMs KiMath Now let s look at another feature available for use with KIM 1 This is a permanent program in read only memory ROM that does several mathematical routines Known as KlIMath the ROM allows nine auto matic calculations ranging from square roots and logarithms to trigonometric functions like sines and cosines This ROM is available on a board that plugs into your Motherboard or which can be cabled directly to the KIM 1 With this math package all sorts of mathe matical routines can be casily written into programs KIMath is like connect ing a calculator to your KIM I with data entered from the keyboard or from memory and results displayed on the LEDs or on the TTY The only way to find out what it really is like to create programs to store them on a cassette to change them and to have this microbrain be the center of a lot of interes
46. build an electrical equivalent that you can put into a box of your choice They re Designed This Way Both supplies start out alike with a line cord and a SPST slide switch Next comes a transformer supplying 125 volts and 6 3 volts AC at 0 6 amperes If you are building the combination supply use both windings otherwise you will only need the 125 volt secondary winding Author packed the components for A and B eliminators into old B case this way Pho to at top of page shows one tube Clapp Eastham regen erative set with 6V motorcycle A and all electric B batteries ELEMENTARY ELECTRONICS March April 1977 From here on we will describe the sup plies separately For the combination supply full wave bridge rectifiers encased in plastic are used They are small easily mounted and have ratings in excess of what we need The Zener diodes are rated at one watt This supply uses a phenolic board with terminals staked into place with the components wired point to point You can use any construction you are familiar with because parts placement is certainly uncritical About the Zener The other supply uses parts similar to the one described above full wave bridge rectifier large filler capacitors and Zener diodes to regulate the output voltages One word of caution if you have never used Zener diodes before Zener diodes come with tolerances of 5 10 and 20 This means that if you buy a 22 2 volt Zene
47. combination CB mount and extension speaker that offers an ideal solution to the problem The system rides neatly on that formely useless transmission hump so that it can t skither around on the floor when you make a fast turn with the car Also specially designed teeth hold the unit firmly in place to keep it from jouncing off the hump when traveling on rough roads And yet when you want to remove the sys tem you just lift it off the hump after unplugging the antena and power leads There s no fussing with any screws bolts or nuts The really neat part is that your CB transceiver and the speaker mount come off as a single unit PIH tell you after mounting my cherished Royce 1 650 rig on a newly acquired Kriket Kamel and trying it out a few times I n d d 1957 became a true believer in the seemingly paradoxical idea that the easier a CB rig is to remove the more secure it is Now don t write in to tell me about those slip in mounting brackets that also make antenna and power connec tions automatically I know that re moval and replacement of the trans ceiver is easy with such a mount But there s just one drawback The thief c n see the empty mount and he may risk tearing your car trunk open on the chance that your CB set is in there he d get special kicks out of letting you know he hadn t been fooled With the Kriket Kamel there s no such telltale evidence because the en tire mounitng unit disapp
48. did divide R in half and you have R1 and R2 Author tries to tune in a Station apparently unaware that the bat teries aren t hooked up to his receiver 2000 RI 2 50uF CI a L James Electronics address is 1021 Howard R2 2000 C2 R3 value depends on filament drain of tube s you power Consult text to figure value T 1 120 VAC primary 120 VAC 15 mA and 6 3 VAC 0 6 A secondaries power trans former Stancor PS8415 or Allied Radio number 705 0034 D1 2 25 VDC zener diodes 1N 56 from James Electronics or equiv D3 3 3 VDC zener diode IN746 from James Electronics or equiv S1 SPST 120 VAC switch 275 011 or equiv Radio Shack Misc AC line cord old B battery or other case wire solder brackets etc Allied Electronics address is 401 East 8th St Ft Worth TX 76102 St San Carlos CA 94070 __ EF k cO OF R 4 R2 equals E volts divided by I amperes To determine the power rating of RI 2 3 use power equation P IPR Power watts equals current amperes squared times the resistance ohms To determine the power rating of the Zener divide the voltage rating by 110 of the load current Then add Continued on page 9I ELEMENTARY ELECTRONICS March April 1977 by James A Fred POWER i panes C BATTER Authentic looking B battery for tube plates and filaments from the AC line It always bugs
49. go Assembles and disassembles in seconds J Pacer did it all for you Mail House P O Box 804 West Caldwell NJ 07006 Check or Money Order only Please 29 95 O bra Shipping and insurance 2 95 O 10 RG 58 U Cable with 2 PL 259 Connectors 4 95 O for quick connection of antenna and radio TOTAL Name Addiess City R SHO Zip 3 4 weeks for deilvery Florida residents add 4 sales tax 16 CIRCLE 41 ON READER SERVICE COUPON assemble are illustrated and described in Lafayette Radio s CB Radio Construction Projects by Len Buckwalter Len is no stranger to the pages of ELEMENTARY ELEcTRONICS he has authored numerous articles since 1963 His book is packed with projects such as S Meter Modula tion Monitor Headset Amplifier TVI Trap Line Filters On the Air Sign and many others You can purchase your copy Soft cover 126 pages 3 95 at national Lafayette Radio Stores or through the home store s mail order cata log Write to Lafayette Radio PR EE Dept 111 Jericho Turnpike Syosset NY 11791 Solid State Data Book A Databook on high reliability integrated circuits and dis crete power devices High Reliability De vices SSD 230 is now available from RCA Solid State Division as a suplement to the SSD 2 OD two volume Solid State Databooks The volume covers MIL STD 883 slash series MIL M 38510 and Gold Chip types for integrated circuits and AN JANTX JANTXV and non JAN types for
50. horizontal expansion so you would need to reduce the Hor Gain horizontal gain setting Reduction in Vert Gain vertical gain would bring the waveform on the right back on the screen For normal viewing purposes the height and width of a waveform pattern should be about equal and Wrong Waveform Displays A should cover about 60 to 70 of the screen On a 9 inch scope this would be a little over 3 inches The pattern should be about 2 inches for a 3 inch CRT Adjustments of the vertical gain contro not only change the amplitude of the signal fed to the vertical deflection plates but they also increase or decrease the amplitude of the signal fed to the sync circuit Quite frequently the change will affect the ionizing potential of the thyratron sufficiently to cause distor tion in the presentation To remedy this adjust the Lock control in the sync circuit Occasionally a waveform frequency wil be en countered that is so high that the frequency of the sweep oscillator cannot be made high enough to give a screen presentation of 2 or 3 cycles If the upper limit of the Coarse Freq control were 50 kHz and the Improper Displays frequency of the waveform were 1 MHz the vertical to horizontal ratio would be 1 000 000 50 000 or 20 1 Twenty cycles of the waveform would appear on the screen at this setting The Vernier adjustment might eliminate a few cycles but the remaining cycles would be too close together to permit observ
51. instant push button selection of VHF and UHF channels 2 through 83 Electroni cally without motors the solid state TRC 82 provides direct access channel changes fine tuning and remote on off control of a TV set from anywhere in the room The TRC 82 all channel remote control is attached to any TV set in minutes It consists of two units an Continued on page 12 CIRCLE 55 ON READER SERVICE COUPON ELEMENTARY ELECTRONICS March April 1977 The 838 though is only one aspect of Midland Power We offer a Complete line of CB s from base stations to por tables to every kind of mobile transceiver that will put our imb in your nds at a very reason ar rice Compare We don t t dy anywhere will give such quality at such ana le price p d LN ine N r IN 2 k L F e E di i S y aM NUMBER 1 MIDLAND CB And we back up that quality th our Midland warranty and onvenlent service centers from Carolina to California want from a CB And finally Midland Power is It s what you get when you the way we put our 15 years of run with number 1 CB experience into u 4 set we build Good experience obviously Or we couldn t have done what e did last year Sell over illion Midland CB radios to make us the number one selling CB in the world Midland Power It s what you hioLano ce A member of the Beneficial Corporation Family CIRCLE 35
52. its screen it may be used to estimate the peak to peak voltage of a waveform placed on the screen A graticule plastic sheet containing horizontal and vertical lines and a voltage standard are required The graticule is placed on the face of the scope and the standard voltage is applied to the vertical plates Phase measurement is another test A known signal is applied to the horizontal amplifier and the un known signal is applied to the vertical amplifier The resulting Lissajous pattern determines the phase relationship of the two signals Lissajous patterns can also be used to measure frequency A known frequency is applied to the horizontal amplier the unknown is applied to the vertical amplifier By counting the number of tan gency points at the top and at one side a ratio of unknown to known frequency can be obtained By multiplying the ratio times the known frequency you can determine the frequency of the unknown You have also learned to study the manual that ac companies an oscilloscope before using it Different Scopes are designed differently The manual pro vides the information necessary to operate and use the scope properly This series is based on material appearing in Vol 4 of the 5 volume set BASIC ELECTRICITY ELECTRONICS published by Howard W Sams amp Co Inc 9 25 50 For information on the complete set write the publisher at 4300 West 62nd St Indianapolis Ind 46268 Build
53. its big 3 field of view gives you more stars ina single view than any other type of telescope Bright crisp finely resolved images to Capture your interest and imagination tt s probably the easiest to use teiescope ever over your shoulder in your lap on a tripod Or just rotate the spherical base on its own mount for use on a table car hood Take it anywhere only 17 10 Ib Top quality optical system 4 f 4 parabolic primary mirror Ve wave 17 F L prealigned a wave diagonal on a coated optical window seals optics from moisture and dust 28mm Kellner eyepiece gives 15X higher without other eyepiece or Barlow Fastfocusing 25 toinfinsty Bright Scharfanian red doesn t impair night vi ion adj Carrying strap A first scope must an deal second scope NO 2001EK 1 49 Ppd FOR GREATER RELAXATION CONCENTRATION listen to your Alpha and Theta brainwaves Do it with an amazing biofeedback monitor This ultra sensitive sensor detects brain Sig mals lets you monitor hear and see your Alpha and Theta brainwaves Great aid to re laxation concentration This portable 8 x 3 x 4 lightweight 24 oz metal unit has a unique electrode headband to slip on or off in seconds without messy creams or solutions Hooked to amplifier it filters brainwaves and signals an audible beep for each Alpha or Theta wave passed You get both audio and visual L E D feedback with this reliable com pletely safe unit It operates on t
54. l New York NY 10001 Please arrange to have the literature whose numbers have circled below sent to me as soon as possible am enclosing 50 for each group of 5 to cover handling No stamps please Allow 4 6 weeks for delivery H6B243 300 Enter my subscription for 9 issues at 4 97 Check enclosed i Add 1 for U S possessions and Canada 2 all other countries 301 302 303 304 305 306 307 308 310 311 312 313 t i 315 316 317 318 319 320 321 322 323 327 328 329 i i 1 330 331 332 333 334 335 337 338 342 344 345 350 352 353 354 355 356 357 358 359 i NAME print clearly i i I ADDRESS l l CITY STATE ZIP i Lom mm m m m E E UR UR RR RR RR RR RR UR UR EU UR E E E E E m m m nn ELEMENTARY ELECTRONICS March April 1977 89 ing the condition of waveforms at selected test points in many kinds of electronic equipment The information obtained can tell you the operating status of a circuit or help isolate the trouble to a single circuit You have practiced analyzing the way circuits oper ate You also have practiced reading block diagrams by tracing signals waveforms from stage to stage Waveform information contained in such diagrams was seen to be useful in checking circuit operation A scope can be used for other tests in addition to checking the shape of a waveform Voltage measur ing is one test Since an oscilloscope has uniform deflection sensitivity inches per volt across
55. like their jobs because the job pays well challenges them and has a good future These are men who have had training And now so can you That s where wc come in We re ICS International Correspondence Schools We specialize in training men and women for skilled careers And while we can t guarantee vou a job no school cando that ICS can give you the first rate training you need especiallv if you re interested in one of the growing careers where ICS concentrates its training AN IDEAL WAY TO LEARN It s not all fun and games But vou can do it in your own home Without the hassle of a classroom Without miss ing a paycheck You get the texts and equipment it takes and all the help vou need If you want to talk to an instructor vou can call ICS from anywhere in the continental United States and Canada using our toll free Dial a Question service It card is missing write ICS Scranton Pa 18515 cox uec i im s tum d A e METERS T m et tus WT i e Tan Ls EUM ee E Since 1890 millions of men and women around the world have turned to ICS for career training More than 70 of America s largest 100 corporations use ICS training for their own employees And the ICS Center for Degree Studies is authorized by the Pennsylvania Department of Education to grant the Associate in Specialized Business degree in Accounting and Business Management and the Associate in Specialized Tech nology degree i
56. limbs he can conrtol virtually all dictation procedures Paraplegics and quadraplegics are al ready accustomed to using similar mouth wands with rubber tips instead of a magnet for turning pages of books Now with no more training than that required by a secretary or executive who has received a new dictating machine the paraplegic has at his disposal the Continued on page 90 ELEMENTARY ELECTRON CS March April 1977 eo e gessi Em TEE Foui E 3i M IF for quality electronic parts and tools OK MACHINE amp TOOL CORPORATION 3455 Conner St Bronx N Y 10475 212 994 6600 Telex 125091 25 CIRCLE 20 ON READER SERVICE COUPON ELEMENTARY ELECTRONICS March April 1977 Nothing is Faster and Easier than ACE for circuit breadboarding Used to be you d get a circuit idea lay out a apes Se pc board print it solder everything together I troubleshoot change your layout try a new i Wem board and spend absolutely too much or time breadboarding Now A P ACE he All Circuit Evaluators let you breadboard in a fraction of the time Make your changes immediately Keep full leads on your components Avoid the heat damage possible with repeated soldering and desoldering And have a pattern for your board if you need a board sitting ia front of you In about as iong as it takes 20 sketch a schematic Get cooking with ACE ACE The All Circuit Evaluator from A P Product
57. line of CB and monitor radio antennas 317 Teaberry s new brochure presents their com plete lines of CB and marine transceivers and scan ners for monitoring police fire and other public service frequencies 31B CBers GC Electronics 16 page catalog offers the latest in CB accessories There are base and mobile mikes and antennas phone plugs adaptors and connectors antenna switchers and matchers TVI filters automotive noise suppressor kits SWR power and FS meters etc 319 Browning s mobiles and its famous Golden Eagle base station are illustrated in detail in the new 1977 catalog It has full color photos and specification data on Golden Eagle LTD and SST models and on Brownie a dramatic new mini mobile 320 Edmund Scientitic s new catalog contains over 4500 products that embrace many sciences and fields 321 Cornell Electronics Imperial Thrift Tag Sale Catalog features TV and radio tubes You can also find almost anything in electronics LIBRARY E 322 Radio Shack s 1977 catalog colorfully iltus trates their complete range of kit and wired prod ucts for electronics enthusiasts CB ham SWL hi fi experimenter kits batteries tools tubes wire cable etc 323 Get Lafayette Radio s new look 1977 catalog with 260 pages of complete electronics equipment It has larger pictures and easy to read type Over 18 000 items cover hi fi CB ham rigs accessories test equipment and to
58. metal the one shown in the photographs is Radio Shack 270 252 How To Connect It The charger s output is through phono jack Jl rather than a direct cable In this way different ee e a G aa gt Poe E vld 1 zn L Aes e M H H Charger can connect to wide variety o NiCad battery packs using the universal cable described in text patch cords can be connected to Ac commodate the several styles of plugs required for transceivers charging jacks Just make certain you get the charger plug polarity correct Before PL2 is wired insert it in the transceiver s charging jack and measure the voltage across the jack noting the plug s polar ity Normally the shield is ground and the tip center conductor Is posi tive but it can sometimes be the other wav round Make certain the charger s positive output connects to PL2 s posi tive terminal You can damage the NiCads badly if you get it reversed Note that most transceivers are dis connected when the charger plug is inserted so don t expect to operate the transceiver while charging the bat teries Using The Charger Resistor RI limits the charger s output to 40 50 mA even if the output jack is shorted so the charger can be used with hand held Continued on page 93 ELEMENTARY ELECTRONICS March April 1977 If you re a typical user of one of those high power hand held CB walkie talkies rated between 3 and 5 watts input yo
59. of the earliest most rare tubes are on display Another interest ing item is one of the water cooled final amplifier tubes from the 500 000 watt WLW radio transmitter I highly recommend the museum to any one who finds himself near East Bloomfield New York There are many related items to at tract the attention of antique radio col lectors In the past Ive mentioned This beautiful 1912 Murdock crystal receiver won second place in AWA old equipment contest tubes literature spark transmitters and horn phonographs Mechanical scan ning disc TV receivers are few and hard to find In this country C Francis Jenkins was the foremost experimenter and had over 300 patents in his name when he died His patent that is most useful to most of us is the intermittent motion of the film in a movie camera and projector As you know the film stops while it is exposed through the lens system It is then rapidly moved to the next frame that is to be exposed A shutter drops in front of the film while it is moving Every movie camera and projector used by amateurs as well as comercial photographers is based on this work and patents of C Francis Jenkins His mechanical TV receiver systems were soon superseded by the cathode ray tube and electronic scan ning The invention he least regarded was the spiral wound cardboard tube His data books models and memori abilia have been collected and presented to the Wayne County Historical Mu
60. printed circuit board or equiv kit solder wire hardware etc in the schematic If you use this cir cuit be sure to feed the higher voltage only to the speaker and not the alarm circuit The maximum allowable sup ply voltage to the CD4001 chip is 15 volts Power Supply The full load current of the alarm is about 34 amperes but this is only when the circuit has been tripped Under normal operating con ditions the standby current is less than 10 microamperes since only the COS MOS integrated circuit R2 and Ri are drawing current The extremely low current drain makes it practical to use eight D cells connected in series to provide 12 volts Such a power supply will last more than a year providing the alarm does not go off Battery operation provides several advantages including freedom to locate the alarm anywhere prevention of a burglar from defeating your alarm by shutting off electrical power and prevention of false alarms due to line voltage interruptions or surges and low cost DC or AC Power It is recommended that alkaline cells Eveready type E95 or equivalent be used These cells can deliver more current than ordinary cells and they last much longer They cost Continued on page 88 ELEMENTARY ELECTRONICS March April 1977 wide tape costs only 3 29 from Radio Shack This tape has an adhesive back ing and it is not necessary to use the full width of tape By cutting the tape in half yo
61. qualities Following are brief descriptions of some of the video projection sys tems now in the marketplace Advent Corp The new Video Beam Model 750 priced at 2 495 is the offspring of the history mak ing granddaddy Model 1000 priced at 3 995 The 750 consists of a three tube projection assembly that is said to project at least 10 times more light than typical single tube sets and a curved screen measur ing six feet diagonally Inside the roll away floor model projector console are three single color tubes red green blue measuring five inches diagonally Each tube is used with a precision lens with an optical speed of f1 4 versus 2 8 or darker lens on many other sets Each lens projects a single color image from each tube to the screen where the three images combine to create a color picture The proprietary VideoBeam screen is easily cleaned as opposed to some other types which are dirt smudge prone and require considerable care to clean The Advent svstem can operate in a room whose light level is just below the brightness level required for comfortable reading Sony Corp Model KP 4000 priced at 2 495 is an adaptation for home use of the firm s earlier protes sional industrial Model VPP 2000 priced over 3 000 The svstem is self contained in a single cabinet measuring approximately 63 inches high by 23 inches wide by 38 inches deep when in operating position The units Tri
62. selection played by a live person the playback switch is flipped and the piano keys hit the proper strings and the original playing is heard The enitre collection consists of many thousand pieces and is the worlds larg est collection of this type The collec tion is available for viewing by the public Continued on page 76 Early transmitter arc type one of several on view in the Antique Wireless Associa tion s Museum 71 e Build B F Brain determined by the value of C1 and will be about five seconds for a 47 uF capacitor If no delay is desired Cl may be deleted from the circuit IC3C and IC3D are considered in a configuration which operates as an astable free running multivibrator DC feedback through R8 and AC feed back through C4 allows the circuit to oscillate at a frequency about 1500 Hertz determined by the RC time constant However the oscillator cir cuit will operate only if there is no input voltage at pin 8 ICIC Thus the latch circuit of ICIA and ICIB con trols the operation of the oscillator The Timing Circuit IC2 is a timing circuit which is connected to operate as an Oscillator The frequency of oscil lation for this circuit is about two Hertz and is determined by the RC time constant of R5 R6 and C3 The voltage across C3 is a sawtooth vary ing between 5 and 9 volts This voltage is fed to ICIC causing the basic fre quency of the alarm oscillator to vary up and down to p
63. single antenna installation more uniform signal pattern because of unique ly detailed phasing design more consistent communications with virtually no fading or blind spots when changing direction in travel Get Outstanding 40 Channel Performance 7 HUSTLER DOUBLE TALK ANTENNA SYSTEM SINGLE ANTENNA Car body creates lop Crossfire radiation with sided ground plane with dual phased antennas re directional signal pat sults in greater coverage tern reinforced signal pattern r NOUR o oO 15800 commerce gione dive t ronics brook park ohio 44142 corporation _ CIRCLE 23 ON READER SERVICE COUPO 12 N ELEMENTARY ELECTRONICS March April 1977 ELEMENTARY ELECTRON ME M E March April 1977 and Electronics Circuits PROGRESSIVE HOME RADIO T V COURSE Now Includes 12 RECEIVERS 3 TRANSMITTERS No Knowledge of Radio Necessary x No Additional Parts or Tools Needed bd EM EENERATOR x EXCELLENT BACKGROUND FOR TV k AMPLIFIER SIGNAL INJECTOR CODE OSCILLATOR xk Sold In 79 Countries YOU DON T HAVE TO SPEND HUNDREDS OF DOLLARS FOR A RADIO COURSE The Edu Kit offers you an outstanding PRACTICAL HOME RADIO COURSE at a rock bottom price Our Kit is designed to train Radio amp Electronics Technicians making use of the most modern methods of home training You will learn radio theory construc tion practice and servicing THIS IS A COMPLETE RADIO COURSE IN EVERY DETAIL
64. slightest background In radio or science whether you are inter ested in Radio amp Electronics because you want an interesting hobby a well paying business or a job with a future you wil find the Edu Kit a worth while investment Many thousands of individuals of all PROGRESSIVE TEACHING METHOD The Progressive Radio Edu Kit is the foremost educational radio kit in the world and is universality accepted as the standard in the field of electronics training The Edu Kit uses the modern educational principle of Learn by Doing Therefore you construct learn schematics study theory Practice trouble shooting ail in a closely Integrated pro gram designed to provide an eaSiiy irearned thorough and interesting background in radio You begin by examining the various radio parts of the Edu Kit You then learn the function theory and wiring of these parts Then you build a simple radio with this first set you wiil enjoy listening to regular broadcast stations tearn theory practice testing and trouble shooting Then you build a more advanced radio learn more advanced theory and techniques Gradually in a progressive manner and at your own rate you will find yourself constructing more advanced multi tube radio circuits and doing work like d urat Radio Technician inciuded in the Edu Kit course are Receiver Transmitter Code Oscillator Signal Tracer Square Wave Generator and Signa
65. that is integrated into a specially notched U Shaped locking bolt It features an extra heavy duty chrome plated holding bracket designed to conform to individual antenna styles as well as a five tumbler corrosion resistant key lock which mates with the special notched U bolt An additional con CIRCLE 47 ON s READER SERVICE COUPON venience offered with Tenna loc is its elec tro polished stainless steel replacement Cup which is used where needed to facilitate quick easy installations For all the facts write to Consumer Products Division Verni tron Corp Community Drive Great Neck NY 11021 Pre Assembled Mobile Antenna Antenna Inc s new Persuader Model 17610 Citizens Band trunk lip mount antenna in pre assembled form will save at least 10 minutes installation time In addition the Persuader Model 17610 now includes the company s in line coaxial cable connector designed to fit through a in hole The improvements are offered with no increase in price over the previous unassembled ver sion of the Model 17610 Suggested resale price of the Persuader is still 25 95 The Persuader comes complete with a base load ed antenna 34 in 17 7 PH stainless steel whip to resist bending and stainless steel impact spring to prevent damage in low clearance areas as well as 17 feet of coaxial Cable with both PL 259 type connector and in line connector and a mount It is designed to achieve a voltage standing wave r
66. the display digits because the display and the clock chip are all on one small as sembly ready to build into a case and connect to a simple power supply a couple of switches and if you like to an alarm If you want to add a couple more switches you can have a clock which displays the seconds on command or which includes the cat nap snooze feature Finally if you want to add one more switch you can include the old feature which makes setting the clock a bit faster The wiring for these extra features is shown in the spec sheet ELEMENTARY ELECTRONICS March April 1977 which comes with the clock module This module is made in several versions by National depending on whether the clock is intended for use in 50 Hz or 60 Hz countries and on whether or not it s intended to display 24 hour or 12 hour time In addition to these features this clock can tell you if there s been a power failure To tell you that the time it shows is incorrect it flashes on and off once every second until you stop it When it s telling time the colon between the hours and the minutes numbers flashes once every second Chip X also tells you whether its AM or PM It does this by showing a dot in the upper left hand corner in the PM Finally when the alarm is set to go off a period at the lower right is lit Press the alarm button to be sure the alarm is enabled ready put S4 on Alarm and go to Continued on next page AS Ld
67. the loop circuit is closed the voltage across Cl is held to about 0 5 volts through the voltage divider action of R2 and Rl When the loop is opened Cl begins to charge through R2 The latch circuit will change state when the voltage at pin 2 approaches 8 4 volts Thus the amount of time delay is S4 SN wE T 6 ea CLOSED LOOP _ Lue 345687 SEE NOTE 2 E 470K 2 i14 LOOP Si EE NOTE 4 mm a E alt LOSE SE OPERATE gt que ft Ts dia SEE NOTE 2 M ois 2 e eee RESET RESET 3 T 1 SEE NOTES 555 Ci afte ICIB 4 au SEE NOTE 1 4 C2 BOTTOM VIEW o L Ul co400 41312111098 Q2 Ji C BOTTOM VIEW ep 63 Qu Q3 p T ac 2N3771 E d C ELEMENTARY ELECTRONICS March April 1977 Complete schematic of system shows the NOR gates IC1A through IC1D which are part of the CO 4001 integrated circuit Circuit may be assembled on perf board if desired Be sure to use IC sockets unless you re experienced soldering directly to ICs Q2 2N3771 i CI VALUE DEPENDS ON DESIRED DELAY 47uF PRODUCES APPROX 5 SECOND DELAY BREAKING CLOSED LOOP OR CLOSING SWI OPERATES LATCH AND SOUNDS ALARM 3 3 RESETS LATCH CIRCUIT 4 2 NORMALLY CLOSED 5S CONNECTED IN SERIES WITH N CLOSED LOOP AND i USED ONLY FOR TEST 69 C It s an unfortunate sign of our times but the burglar alarm is becoming a necessary part of home electronics Rob berie
68. these holes from either the front or the back of the module but you will probably ELEMENTARY ELECTRONICS March April 1977 by Norman Myers Take just 8 parts and a couple of switches connect this module MOD X THE SIMPLEST CLOCK VET to mane an alarm Clock in less than two hours Dozens of clock projects have been published in the past three or four years and they all have two things in common an integrated circuit which contains most of the counting and tim ing circuits for making a digital clock and ots of wiring especially between the integrated circuit chip and the read out devices These range from Numi tron or other multisegment display tubes for each number to the more recent and easier all in one 7 segment LEDs which have four or six digits in one compact assembly Even with their maze of intercon necting wires many of these clocks offer only time and usually an alarm Some but not all permit you also to read the seconds as they elapse and more and more have the Cat nap snooze feature Now thanks to today s improved methods of IC manufacture and mass CLOCK MODULE ALARM BUZZER production which continue to bring prices down down down National Semiconductor Corp has brought out a complete clock on a chip including the readout display the numbers which show the time You no longer have to connect the outputs of the circuit chip which does the computations to
69. via long life nickel Silver contacts No special patch NO OF PB 6 630 PB 100 760 PB 101 940 PB 102 1240 PB 103 2290 PB 104 3060 PB 203 2290 PB 203A 2250 Manufacturer s suggested list Prices and specifications subject to change without notice PARTS 14 PIN DIP SUGG MODEL TIE POINTS CAPACITY LIST 6 24 32 24 24 15 95 19 95 29 95 39 95 99 95 79 95 75 00 120 00 OTHER FE ATURES Kit 10 minute assembly Kit with larger Capacity 8 distribution buses higher Capacity Large Capacity moderate price Even larger Capacity only 2 7 per tie point Largest Capacity lowest price per tie point Built in 1 regu fated SV 1A low ripple power supply As above pius Separate 2 amp 15V and 15V internally adjust able regulated outputs cords or Jumpers needed just lengths of ordinary 22 30 AWG solid hookup wire Circuits go together as quickly as you Can think them up And parts are re usable so as your junk box builds you build more and more projects for less and less money Before you invest in your next project investin a CSC breadboard See your dealer or order by phone 203 624 3103 East Coast or 415 421 8872 West Coast major charge cards accepted You ve got nothing to lose and alot to gain CONTINENTAL SPECIALTIES CORPORATION 44 Kendall Street Box 1942 New Haven CT 06509 203 624 3103 TWX 710 465 122
70. you don t have to violate a single FCC Part 95 rule to do it Some awards are easy to walk away with others are a bit rough some take an enormous amount of skill and effort Those who qualify are rewarded with a beautiful blue and black 8 x Il certificate to adorn their wall These awards are presented by The Sidebanders Service Bureau P O Box 381 N Smithtown N Y 11787 The Sidebanders Service Bureau is the larg est and oldest Sideband Network The SSB Network around but anybody can qualify for their awards even AM operators To obtain a free copy of the rules of their many awards send a Stamped self addressed envelope to these people More Than Meets The Eye As you can see there s more than meets the eye in CB radio as it evolves and grows many developments are Only known to the in crowd We would caution you to be familiar with Part 95 and to fol low it closely the fact that we are reporting certain violations to you does not mean that we endorse them how ever you as an active CBer should be as well versed as possible on what s taking place a 1907 pps HERE The Most Advanced Design CB Base Antenna Anixter Mark introduces the new Mark AMB 2 the space age version of the famous Mark IlI Super Beacon with more advanced features than ever before in a base station antenna e Full half wave design Tuneable to reduce the effects of nearby objects amp the detuning as height v
71. 1 customized for your i CB STUNTS THAT YOU SHOULDN T KNOW 2 0 Ge Pr MARCH APRIL Q 1977 FOR 21 98 BEGINNERS 2o HOW TO USE SS OSCILLOSCOPES LL OUR BASIC OUR BASIC COURSE PROJECTS i GADGETS MOX E rro ever designed for hobbyists Basic control module for Burglar Fire alarm systems home Power up those antique radios er from our authentic battery case that plugs into the AC line s d I s a n t i a P g a lt e r F m s r E 5 La gt S _ i n LJ x J I E i I E y d F Fil if P A E s H j p 3 H1 S i f S i s j 1 s B T E i wel P i e Sa 5 m 1 i 1 a P P i 1 E at qu i l Y E Play sweet music in remote rooms The KIM 1 is an excellent beginners computer for learning theory and playing exciting games Projection TV Hump mounting CB Rigs Heath speaker kit DXing Columbia amp Venezuela and lots more D A DAVIS PUBLICATION NOBODY SHOULD HAVETO WORK Tao ordo sdb dk mtr Em un amp Aunt dtt KFREALISTIC hae Pao WES aac F Eas 660 Piten 08 AT UN x HAI FPEALISIIC S000 SATE COMMUNICATIONS accents aa Uni a E UP Re RI a A PING Al with the Realistic DX 160 Receiver Full feature design for o listen
72. 1 A sine waveform at moderate voice level produces almost 100 percent modulation on this transmitter But adding a powermike overdrives the preamp and modulator exceeding 100 percent modulation with re sultant distortion and side band splatter Fig 2 yah 4 Ne Fig 3 struction of the transistor produces dis tortion through greater than 100 per cent modulation if the transmitter isn t limited to 100 percent modulation and most transceiver built until 1976 are not limited to 100 percent regardless of their manufacturer s claims or dis torts if the transmitter zs limited to 100 percent modulation In case you tend to doubt that many transceivers are not limited to 100 per cent modulation of 25 models recently tested by the FCC 23 did not provide 100 percent modulation limiting even though the manufacturers had claimed 100 percent limiting Figs 1 and 2 shows what often hap pens when a CBer uses a powermike Fig 1 is the RF output of a transceiver specified by the manufacturer to have 100 percent limiting when a 1000 Hz sine waveform at reference voice level is fed into the microphone Note that the negative baseline modulation is Just short of 100 percent at 100 per cent it touches the bascline Fig 2 is the same transmitter using a popular powermike with the powermike s level control turned fully down This mess of distortion is what s transmitted and there is negative overmodulation
73. 1 AA Newport Beach CA 92663 BEAUTIFUL MEXICAN GIRLS Wanting American Boy Friends Details Photos Free World Box 3876 DC San Diego CA 92103 DATES GALORE Meet singles anywhere Call DATELINE toil tree 800 451 3245 OVER 1000 beautiful ladies photos world s largest matrimonial catalog 5 00 Interpress Box XT a M4A 2Mb or Box 737 Ft Lauderdale ADULT pleasure products over 600 items Glant catalog 1 00 Clifton s D 1068 Saugus CA 91351 LATIN AMERICAN GIRLS apreciate thier men Let us introduce you to a dark eyed unspoiled beauty Complete application package and photo selection Only 2 00 Maria Garcia Box 80801D San Diego CA 92138 BEAUTIFUL MEXICAN GIRLS Correspondence Photos information 1 00 Latins Box 1716 DB Chula Vista CA 92012 RADIO amp TELEVISION TV TUBES 36 each Send for Free 48 page color catalog Cornell 4217 W University San Diego Cal ifornia 92105 TUBES Oldies latest Supplies components sche matics Catalog free Stamp appreciated Steinmetz 7519 EE Maplewood Hammond IN 46324 DISTANCE Crystal Set Construction Handbook 50e Coll Winding 50c Catalog 25 refundable Laboratories 1477 G Garden Grove CA 92642 REMAILING SERVICE CONFIDENTIAL Remail forwarding reciving ser vice rates by month or letter For information 7522 Loma Verde Wy Sacramento CA 95822 RUBBER STAMPS RUBBER stamps made Th
74. 100 200 iiodes at these prices 03 s 560 series 555 in lregisters flip flops count Compact 100 600 800 and 1000 Cat No 2L 2418 Untested rludes 21 2416 ers 2L 2415 Intest low price o E Kronos at an alarmin 13A 6 DIGIT New from im of your hand only 442 Foe amp it fits in pa any room or for OR Beautifully TEDI Attractive gray mane Pushb IGIT dc e trimmed transparent red pens ee 4 D teh s control alarm time real time pu I M ee a set snooze Uses famous e i ALAR a D Sib and minimum of parts Comp A CLOCK step by step instructions Wt 10 ozs No G Poly Paks Inc Wakefield Mass U S A 1977 ELEMENTARY ELECTRONICS March April 1977 Time LINEAR 7400 DIPS MOSFET TRANSISTORS PRECISION RESISTORS POWER TAB TRANS D 100 for 60 for 200 for 40 for 2 1 98 1 98 Ze 1 98 9 P 1 98 Z Marked and unmarked Wa Marked and unmarke m AIH 4 leaders TO 18 case As plastic TO220 type ternal numbers of raw fac includes UHF transistors V2 2 watts No 2 2417 Assorted 2N numbers ory stock Mo 2L 1431 too Cat No 2L 2429 Cat No 2L2426 Untested BARREL KIT 711 BARREL KIT 10 BARREL KIT 7 POWER TAB ROMS REGISTER VOLUME CO TRANSISTORS is A Ei BARREL KIT fa SUBMINIATURE Terms Add postage Rated net 30 Phone Wakefield Mass 617 245 3829 Retail 16 18 Del Carmine St Wakefiel
75. 1977 by Kathi Martin KGK3916 I m beginning to think there s some truth in the notion that given enough time even the most useless thing in the world will ultimately serve some good purpose Take that confounded trans mission hump on the floor of your car for example It s always been a nui sance But now it s just what you need to improve the audio performance of your mobile CB unit and at the same time protect the rig from being ripped ott First let s consider the rip off prob lem Maybe you already use a key locking mount which at least thwarts the more timid sneak type thieves who plunder unlocked vehicles from which CB units can be quickly removed by unfastening a couple of wing nuts But the more determined and experienced Lightfingered Louie isn t fazed by a key lock he just inserts a small pry bar in the right place and in moments liter ally tears the mounting bracket off your dash He s not in the least concerned about the damage he also does to the Car The only truly reliable anti theft sys tem is one that permits removal of the CB rig quicklv and easily so that it can be put out of sight in the car trunk or be removed from the car entirely But you and I know that if even two wing nuts have to be removed to disengage ELEMENTARY ELECTRONICS March April 4 1 j ane P iu the unit we won t bother half the time The Kriket Kamel Model KC 3085 by Acoustic Fiber Sound Systems is a
76. 6 G E 3 5 WATT 2L 2733 Untested Cat No 212730 BARREL KIT 40 PNP HIGH POWER ail good Cat No 2L 2729 BARREL KIT 739 2N3055 HOBBY 1 98 10 ar 1111 E07 BONANZA AMPLIFIERS TRANSISTORS TRANSISTORS RECTIFIERS Untested 1100 for 1 9 50 for 1 98 25 for 20 for 15 for 3 100 for 1 98 rce JdiWCHbuE i d Bargain 8 a lifetime Ati Barrels n barrels of em Famous style asstd volt p EU idees we got was barrel thej This is a buyer s market 1 98 1 98 1 98 Sees Silicon a0 UEM resistors 3 to 7 watts blisdor digit types Mutti How many can we get test Hobby type factory fall Popular germanium TO 3 Fallouts of the famous ali types of voltages t Cat No 2L 2724 plexed Cat No 2 2722 ed Cat No 2L2626 outs 2L 2624 Untested case 2L 2618100 good 2N3055 2L 2617 100 3KV Cat No 2L 2615 BARREL KIT 735 BARREL KIT 731 BARREL KIT z305 BARREL KIT 27 BARREL KIT 26 BARREL KIT 25 BARREL KIT 20 NEON LAMPS 4 Bez iavons PREFORMED PREFORMED DISCS PLASTIC METAL CAN LONG LEAD DISCS 30 for 100 for 1 98 RESISTORS 100 tor TRANSISTORS 100 for ba 00 1 98 100 good Made mostly by Corne 2 for 98 Er 100 for 1 98 1 98 pmi Famous NE 2 s Ail prime the finest resistor made e S veu de nd Hi Fi mfr s shelf inventors 1 98 Untested Includes TO 5 TO 1 TO s but factory made millions
77. 7 West Coast office Box 7809 San Francisco CA 94119 415 421 8872 TWX 910 372 7992 Canada Len Finkler Ltd Ontario 1976 Continentat Specialties Corporation CIRCLE 16 ON READER SERVICE COUPON BOOKMARK BY BOOKWORM Solid Basics Sotid State Electronics by Frank P Tedeschi and Margaret R Taber provides an introduction to fundamental semiconductor and electronic principles Its use requires only a familiarity with al gebra and basic electricity The book is conveniently divided into eleven self con tained sections each concentrating on spe cific semiconductor components Numerous example problems and laboratory experi ments bridge the gap between theory and practice and provide a more comprehen sive working knowledge of actual electronic components in practical circuits Rein forcing the theoretical ideas are a wide variety of illustrative aids such as graphs curves tables diagrams formulas and ac SOLID STATE ELECTRONICS FRAI D TEDESCHE M n e rd Mii d Hard cover 202 pages 8 95 tual wiring circuits In brief this volume aids in mastery of basics that enable pro gression to sophisticated semiconductor principles such as feedback amplifiers field effect transistors integrated circuits and SCR s Published by Van Nostrand Hey CB er No roof to c Reinhold Company 450 West 33rd Street New York NY 10001 Down With Trouble Here s a book on how to troubleshoot basic electroni
78. 714 en NATIONAL BUSINESS COUNCIL Needs Distribus ters Amazingly pro table Details NSBAC Box 1127 Topeka KS 686801 30 00 PER HUNDRED stuffing envelopes Imme diate earnings Beginners kit 1 00 Refundable DTFG 114 Canterfield Drive San Antonio TX 78240 STUFF ENVELOPES 250 THOUSAND SUPPLIES Enclose STAMPED Envelope Enterprises Route 1 Box 263A3 Pauls Valley OK 73075 EASY sparetime work home Big Write Jones Rt 2 Box 133 A Arkadelphia AR 71923 NEW Stuff our circulars for profit Details free Cooper 2108 Yale St Louis MO 63143 1 000 MONTHLY possible stuffing envelopes Free details Productive Box 26 Ericsburg MN 56640 BUY IT WHOLESALE 1 CB Radios Sell from your home large profits Send 1 00 for catatog refundable on first order to D Discounts P O Box 602 E Glendale AZ 85311 602 249 0547 SAVE MONEY 2 Giant Wholesale Catalogs 3 00 Refundable 1st order Winchester Enterprises 2807SS Hargrave Street Phila Pa 19136 STRATUS HOVERCRAFT Flies over land or water Completely portable Details 1 00 Unique Sales P O Box 534 Nitro WV 25143 CB RADIO CB Slang Bear Country Those Crazy Handles more in Jason s CB Dictionary Must reading Good Buddy 3 00 Triour Products Box 369E Kokomo IN 46901 w DETECTIVES POLICE SECURITY INVESTIGATIVE schematics and equipment listings Quimtronix Box
79. 98 Gut 1 or Resistor factory tried to or 9 100 for 1 98 connectors from 1 contact C Asst GE types CDS types i01 us hy mixing 100 Cosmetic rejects electri Axin l rei case variety o pd manufacturers 1 98 m EN v a la D eed by factory EN color coded resistors in gav fine business You physical sizes amp values arrel dump is your gain atters on Bi or us to separate barrel But value is there Check em it s not for us Cat N L 3018 Wt 1 b Cat No 2L 3156 Cat No 2L 1057 100 good 2L3054 good Cat No 2L3052 y A oz 2L 3046 Untested isst voltages 2L 3204 cim BARREL KIT 788 inate 100 for 40 for 10 for 1 98 1 98 1 98 s T8 urles Types 8000 100 series Tae T27 s ples et to 0 4 PTLs ROMs registers clack ples ete 33 from factory 1 ised amp cale ehlps linear et from factory have fun No 2L2861 BARREL KIT 773 Cat No 2L 2860Untested BARREL KIT 71 have fun 2L 285 up to 300 mf Cat BARREL KIT 56 POWERS POWERS 2L2747 100 good Cat No 2L273B ARREL KIT 54 DIGIT READOUTS Ali marked Cat BARREL KIT 86 NATIONAL IC BONANZAHOBBY LEDS BARREL KIT 768 x TRANSISTOR CAPACITOR SPECIAL 2 WATTERS MIXED READOUTS MIXED IC S POLYSTYRENE CAP E SWITCHES Y ELECTROS 100 pcs 100 for 10 for 1 98 Ed 100 for 100 for 30 for 1 98 50 for 1 98 1 98 1 98 a Factory returns such 1 1 98 E aupra ua NCC E n
80. ARED CODE PRACTICE LETTERS NUMBERS PUNCTUATION CODE GROUPS WORDS CASSETTES ARE DESIGNED TO MINIMIZE LEARNING PLATEAUS 0 6 WPN Novice License 6 CASSETTES 1995 0 8 WPN Novice License TCASSETTES 2295 7 14 WPM General ClassLicense 3CASSETTES 9 95 First class postage required per CASSETTE 040 THE HERRMAN CO Dept O BOX 1101 LARGO FLA 33540 ow or McGEE S BIG SPEAKER CATALOG 1001 BARGAINS IN SPEAKERS PARTS TUBES HIGH FIDELITY COMPONENTS RECORD CHANGERS Tape Recorders Kits Everything in Electronics 1901 McGee Street Kansas City Missouri 64108 TV JAMMER Amaze your friends Makes TV s go into distortion Max range 20 IN EASY KIT FORM 2 65 SEND FOR FREE CATALOG ELECTRONICS COMPANY RX 6827 Tobias Av Van Nuys Ca 91405 348C UHF POLICE CONVERTER Permits the reception of police calls in the 450 470 MHz range with any car radio at the flip of a switch Sensitive easily installed will not inter fere with regular BC reception Complete nothing else to buy 39 95 postpaid KUHN ELECTRONIC PRODUCTS CO 1801 Mills Ave Norwood Ohio 45212 Shortwave Listening 1976 World Radio TV Handbook 10 95 Gated 1000 100 50 25 10 kHz Calibrator 54 00 Barlow Wadley amp R L Drake Receivers 1976 Confidential Frequency List 5 45 GILFER Box 239 Park Ridge NJ 07656 HIGHLY PROFITABLE ONE MAN ELECTRONIC FACTORY Investment unnecessary know
81. B license F S Los Angeles CA Heck no There is however a require ment that you are not an agent for a for eign government and that goes for citizens and aliens alike Should you be barred from getting a license for this reason the FCC may waver this rule should you state that your station would be used for per sonal reasons and not for business Sunk l have a Lafayette Micro 66 CB rig and l live in a canvon and can t get my signal out What do you suggest B H Goleta CA Start a landfill project Or maybe a 60 foot tower would help Thought in Harness Ils co phasing two antennas that im portant or is one antenna really enough K D So Fallsburgh NY If you are using two antennas on one vehicle yes If you are using one antenna and would like to know if two are better yes But let me say that two antennas do not give you twice the signal one would offer Two antennas give an improved om nidirectional radiation pattern over a sin gle antenna Of course we are talking about mobile antennas mounted on one of the worst ground planes in the world your car The harness of cables interconnecting the antennas and the CB set do two things of importance One the harness provides the correct cable lengths so that the an tennas will be in step with each other and two the harness provides impedance matching for minimum SWR and maxi mum power transfer This is co phasing and it may be important to
82. Battery Charger Continued from page 50 transceivers that use ten rather than the usual twelve NiCad batteries Re gardless of the number of batteries the charging current remains a safe 40 to 50 mA Normally 14 to 16 hours will be required for a full charge so this can be done overnight If you want the batteries maintained fully charged and ready for use at any time you can keep them on continuous trickle charge The only caution is not to try and charge two or more hand helds at the same time Don t make up a Y adaptor that connects two or more hand held battery packs in parallel be cause one pack will discharge into the other and if there is a weak cell in one pack the other pack will discharge with excessive output current Charge only one set at a time It s Sound Cookie Continued from page 46 plastic end of the screws Now place the metal retaining ring from the grille assembly on top of the plastic cover and mark the four holes for securing the ring to the speaker assembly cover Remove the ring and make holes in the plastic right through into the Masonite with a sharp nail a scriber or a small drill Make the holes only about half the depth of the Masonite Now take the four self tap ping metal screws and after replacing the retaining ring right side up on the assembly with the holes lined up screw the whole thing together The self 93 92 It s new And it s from Isa
83. CE M e Where to get it Equipment parts sup plies and services Hard to find and standard items at bargain prices Over 600 places to find transceivers antennas surplus new and used equipment wPs com puters ICs components assortments assemblies discounted items test equipment peripherals etc Hundreds of large and small mail order sources A complete directory divided by sources items and locations Saves count less hours of shopping Easily pays for itself through comparative buying Contains no advertising Rush my order enclose 5 95 plus 554 g postage and handling Californians add D 39 sales tax Full refund if not completely satisfied within 10 days U Name Address E 1 F BISineZp B Primary interest Amateur Radio O CB O 0 Experimenting O uPs Computers O Send to Peninsula Marketing i Dept H 8 g 12625 Lido Way Saratoga CA 95070 PpPaonssnnonannoon my 32 DX central A world of SWL info Bv DoN JENSEN How does a major international broad caster select its program schedule when it will broadcast to certain areas of the world And how about frequency selec tion How are the shortwave frequencies picked and why do they change at least several times a year First the schedule selection is a rela tively easy matter To a great degree the when is determined by the intended audie
84. ENT Moneymaking opportunity Work 95616 Details free Noon 779 M St Davis CA 5616 MAILORDER Millionaire helps beginners make 500 weekly Free Report reveals secret plan Execu tive 1G1 333 North Michigan Chicago 600601 GUARANTEED secrets of stuffing envelopes Free Wayne Box 581 Ottawa KS 66067 AMAZING Possible mailing letters Details DN Glothlin 508 W Mulberry Porterville CA 3259 GUARANTEED secrets of stuffing envelopes Free Wayne Box 581 Ottawa KS 66067 BUSINESS OPPORTUNITIES Cont d CARPETS RUGS WHOLESALE MAKE big money spare or full time selling carpet to friends build e s apa tments Work from your home low Dalton GA Mill prices start at 2 39 yd Many styles avail able Get started now in your own business Send 15 C0 Refundable for professional sample kits of three fast sellers Owen Carpet 248 EE Resaca GA 30135 or call 404 277 1321 GET RICH with Secret Law that smashes debts and brings you 500 to 2 million cash Free report Credit 4Gi 333 North Michigan Chicago 60601 300 WEEKLY Stuff envelopes Addressed stamped enve ope Aquarius Box 18438 Milwaukee WI 53218 STUFF envelopes secrets Free details Excell 517 Ave Y Birmingham AL 35214 FREE details on stuffing envelopes for Write Ackerman Pike NY 14130 1 000 MONTH easy plan Details free Goodale 15052 Glass Cir Irvine CA 92
85. ERVICE COUPON buddies have built a cult of together ness Featured on the album are Hey Shirley This is Squirrely which has already become popular as a single The Night talked to the Lord The Handles Hall of Fame and Hey Good Buddy Where s My Baby which are also ex pected to be released as singles Other songs on the album are Honey Bee Please Answer Me Come On Come On CB Baby Everybody s Somebody In Our CB World Listenin CB Blues Ain t Ever Gonna Be Lonely Again and L J s CB Radio All Ears priced at 3 49 is available on stereo LP or 8 track tape exclusively from Radio Shack stores and dealers nationwide Intelligent Terminal A sophisticated all on one board kit for use as either a computer or intelli gent terminal is now available from Pro cessor Technology Known as the Sol Terminal Computer the new kit with all memory and interface electronics in cluding video display keyboard inter face audio cassette interface al neces Sary software plus the ability to accept the Processor Technology line of memory and interface modules sells for 475 in kit form The Sol can be used as a microcomputer low cost CRT terminal and editing terminal Built around the 8080 microprocessor the Sol termina consists of a PC assembly with the microprocessor 512 eight bit bytes of PROM on a plug in personality module 2048 eight bit words of RAM a 1024 character
86. For valuable soldering information send self addressed stamped envelope to Kester for a FREE Copy of Soldering Simplified H KESTER SOLDER Litton 4201 WRIGHTWOOD AVENUE CHICAGO ILLINOIS 60639 CIRCLE 11 ON READER SERVICE COUPON NEWSCAN a joint development of the two com panies The range itself is being built by the U S Navy for the U S Air Force under a Joint Service Program The key to the savings was to design a prefabricated tower with a large mat type foundation After it is built the tower is floated to its location in deep water and then sunk The tower is stabilized on the ocean floor by weight and friction The Air Force quickly saw the ad vantages of these soil supported tow ers over conventional pile type which would have cost more than two or three times the amount to build and erect In contrast to the conventional pile type designs which were used for radar EF The above 200 foot tower is being built for the U S Air Force using technology borrowed from the oil industry It is part of an offshore pilot training range at Tyndall Air Force Base Florida The towers are floated into position and then submerged Weight and friction hold the tower in place stations in the Atlantic Ocean some years ago the soil supported design has no need for extensive offshore construc tion equipment during installation or removal of the towers years later For Continued on page 26 C
87. L KIT 163 BARREL KIT 7161 MINI TRIM POTS POP PLASTIC BARREL KIT 30 for io TRANSISTORS 15 for M tt 12 for 75 for Eu 1 98 25 for 1 98 1 98 A gt 1 Sg tH 1 98 w 7 1 98 uo i 2N3904 s with some men Centralah KTyypy seg readout with buitt on Nylon white cable connec We gathered an assortment Asst values 100 to 1 megj 2N35306 s of 100 mute LM309KC TO 3 What a buy Single turn rial TO 92 Preformed reled Bot by l4 W Wt 6 oz 2L3345 Cat No 2L 2343 loz No 2L 3330 IBARREL KIT 145 BARREL KIT MINI 75 PC TRAN TRANSFORMER BARREL KIT 144 RCA PHONO PLUGS 40 for 1 98 throughout the United States buy from various factories their over the same Therefore you are getting RE TESTERS Do TEST EM YOURSELF N SAVE hs V REGULATORS 1 98 4P CITIZENS BAND POWER SUPPLY 12 VDC ED CONTINUOUS DUTY e convents CB HAM RIGS TO HOME 3 AMPS t 115V to 12VDC converter ds Huilt in automatic RESET A circuit breaker Powerful 3 Every kj Carries 4 Money back Siaran tee Avg Ship Wt 6 ozs YOUR amps 8 amps peak makes it ideal for SSB rigs too INCLUDES tt Of gt gt l lik etal CHOICE 1 00 modern design eubinet A OF ATERIA amp 7bx214 Rig us ANY L i de xin Built in cir cenit breaker Front has OFF ON switch and LED light For 115 SEN 14
88. LTIPLEX RECEIVER COLOR BAR DOT Ob e ad GENERATOR m 1 J UA Fe 4 1 88 321 MEL pU PERLE AE FET VOM AM FM SW PORTABLE SOLID STATE RECEIVER x VECTOR MONITOR SCOPE Solid State B amp W TV SIGNAL GENERATOR DIGITAL SOLID STATE 2 METER FM ay MULTIMETER TRANSCEIVER amp POWER SUPPLY POCKET RADIO 5 OSCILLOSCOPE tion privileges spelled out Make your own com p m ee ee E GE GE GEM OD ic i NATIONAL TECHNICAL SCHOOLS Dept parisons your own decision Mail card today or 4000 South Filberoa St Los Angeles Calif 90037 TYPES clip coupon if card is missing i Please send FREE Color Catalog and Sample Lesson NO OBLIGATION NO SALESMAN WILL CALL P f Color TV Servicing C Electronics Technology NO OBLIGATION NO SALESMAN WILL CALL 1 C BAW TV ont Radio Servicing LJ Caduta Elpetromes Electronic Communications C Basic Electronics APPROVED FOR VETERAN TRAINING FCC License Course Audio Electronics Servicing Get facts on new 2 year extension NAME AGE 7x NATIONAL SCHOOLS gs ph id CITY STATE zm TECHNICAL TRADE FRAI N ING SINCE 1905 Please fill in Zip Code for fast service EN Resident and Home Study Schools Check if interested in G I Bill information 4000 So Figueroa St Los Angeles Calif 90037 O Check if interested ONLY in classroom training in Los Angeles Ea cns eee m ee ALL NEW SOLID STATE OSCILLOSCOPE
89. ON READER SERVICE COUPON T X p A aoa m ogee ie e UB i IT S WHAT YOU GET WHEN YOU And once you get it it s going to For 1977 the power comes to clarity The 838 s also power ip be all you ll ever need Because youin an entirely new genera your hand w n automatic Midland gives you what CB is tion of 40 channel CB radios channel adva and volume suppased to give you The power Spearheaded by the remarkable control right he mike And to communicate The power to Midland 838 it s the power tc know exactly reach out and pull in your own With it comes switchable where you re heading with our personal horizon And the automatic noise limiter noise large bright L E D digital clarity to be understood blanker and audio filter three channel indicator i wherever you reach noise elimination systems that o let you receive with greater es Shakespeare comes cn strong for the new 40 des M channel era With high perfcrmance CB antennas BR m j that tu n on the power on al 23 or 40 channel MET B CBtransceivers E _ Shakespeare s new White Knight Antenna combines the rugged mechanical strength of gleam ing white fiberglass with precision engineered elec Ai tronic components Corm ponents like the high quality loading coil permanently fused in a solid polycar P 2o 7 e bonate thermoplastic base Totally impervioustothe gt
90. ONIC SOUND CATCHER No 1649EK REQ 29V BATT KNOW YOUR ALPHA FROM THETA 110V FUEL MISER RECLAIMS HEAT No 19 194EK 5 DIA Shpg 17 Ib 121 50 FOB Sea Pee 5 lind CAN T SLEEP RELAX TRY THIS iN c o ey coated optics 393 ft field of view Only 2 oz stores in pocket purse glove box No 1568EK 14 95 Ppd SEE MUSIC IN PULSATING COLOR A rcm ninm 0 fee No 42 309 EK ASSEMBLED 18 50 Ppd No 42 336 EK UNASSEMBLED bie No 1668 EK 9x5 9x 44 ole ae aa 149 95 Ppd No 71 809EK FOR BEGINNERS 59 95 Ppd AN ULTRA MINIATURE AM RADIO Antenna assist has pulled in stations up to 1000 miles off No wires clips grounding Solid State no elec batts tubes No 72 095 EK 19 95 Ppd ULTRA SELECT A TENNA OVER 1000 MILES _ No 72447EK 24 95 SUBJ TO LOCAL COND Top quality Spy Scope a 30 value now 14 95 Special pur hase saves you 50 10096 J Channel Color Organ lets you modulate 3 independ strings of colored lamps w intensity of your music Audio light show flashes responds to rhythm prich 15 95 Ppd The Astronauts used this super 20X60 binocular modified to view Earth Big 60 mm objective lenses 173 ft field of view at 1000 yds Relative brightness 9 0 Fully coated optics more Parabolic mike w 1834 trans arent ref
91. Over 100 great easy to build plans Send 1 25 com pele y ieiunded with your first order BOAT BUILDER CP Div 229 Park Avenue South New York NY 10003 BOOKS amp PERIODICALS WHAT S going on in housing Get advice on how to economize in modernizing or improving or adding space from idea to completion Working blueprints available Send 1 35 for 110 Better Building Ideas to Davis Publications Inec 229 Park Avenue So oh 10003 INCOME Educational Professional Sports Music List 25c Wright s C 222 S M Clintonville WI 34929 40 BOOKS for only 5 00 Clearance Many cate gories Free details Shorefire 1 Scofield Norwalk 06855 FREE Magazine featuring 450 books natura health gardening occult other interesting subjects Provoker Press Lakeshore Rd St Catharines 579 Ontario L2R 7C89 INFORMATIVE HANDBOOK For people with an interest in electronics and desire to know more Covers basic electricity resistors capacitors micro waves facts on frequency about fuses circuit break ers crystals and much more Send 1 50 for your copy includes postage to Electronics Theory Handbook 229 Park Avenue South N Y N Y 10003 BUSINESS OPPORTUNITIES p MAKE Magnetic Signs Big Profits Details Universal Lenora KS 67645 HOMEWORK BIG MONEY addressing mailing envelopes Exciting offer 10 Linco Services 3636 Peterson Chicago 60659 BUSINESS OPPORTUNI
92. P O Box 3812 Portland ME 04104 A Anyone have the diagram and parts list for the RCA Home Study Course Volt Ohmmeter If yes write to M J Lavan dor 4057 Alper Lincoln Park MI 48146 A Ed P Harmon of 12700 2nd St Apt 46 Yucaipa CA 92399 needs the circuit diagram for the Grundig Transistor 1000A S channel rig A Got the instruction book for the Trio Model 9R 59 receiver Then write to Ed Perreaux 235 Forsyth Cris Regina Sask Canada A Walter Baker of 162 No Queens Ave No Massapequa NY 11758 needs the schematic diagram and info on the Mirin da Nocturne tape recorder A James Cummins of 249 Hampden Si Chicopee MA 01013 needs the schematic diagram for the Engineered Electronics PR 10 power supply A Charles Howard of 608 Aetna St Salem OH 44460 has an Ozarka_ radio and would like to kn w about it and its value A Sorry we cannot handle requests for equipment sales Why not try our Classi fied Ads Section A A Murdock Neutrodyne radio 3 gang tuning and 5 tubes needs fixing and UV 201A tubes Send help to Michael Perry 6118 Ellen Drive Goodlettsville TN 37072 A Vern Kleinendorst wants the Lake Su perior ore ship frequencies Send info to 1815 River Rd Grand Rapids MN 55744 A A Symphonic TPS 30 solid state TV needs a new transformer and Jay Surdyka needs help Write to him at 4 Goodrich St Hartford CT 06114 A Jerry Bolin of 16576 Sarah St Mojave CA 93501 can use an FM
93. Shure CB45 Noise Can celling Controlled Magnetic Micro phone dual impedance shown on the right in Fig 3 This mike is really one of Shure s pro models with a CB identification number It is designed to respond only to close in sounds and is used actually touching the lips It is in sensitive to extraneous sounds such as road noise so it puts out a really clean mobile signal and without need for an amplifier To give you some idea of the quality built into the Shure CB45 it weighs two to three times more than a typical mike supplied with a CB trans ceiver and most of the weight is the microphone element And you know that little clip supplied with mikes that you screw to the dash to hold the mike Well the one supplied with the CB45 is literally a work of art costing more than many so called CB replacement mikes As for amplified mikes I just don t dig them unless you want to sit back in a nice quiet office and speak low or mumble But if you want to relax then one of my favorites is the Shure 526T shown on the left in Fig 3 The mike element in conjunction with the ampli fier which is powered by a standard 9 volt battery provides a boost to the midband frequencies resulting in mod ulation that literally cuts through QRM But and this is a big but the mike works great if the level control is turned all the way down If the level control is turned up the sensitivity is so sharply increased the mike will pick up e
94. TIES Cont d FREE Secret Book 2042 Unique Proven Enter prises Fabulous Little Knowns Work Home HAY LINGS E14 Carlsbad CA 92008 BECOME our Mall Order Distrih tor with 150 investment Free brochure Audit Controls 35 Brookside Ave Fair Lawn NJ 07410 BORROW ANY AMOUNT Hj A 1 credit Keep money in bank get 80 more Send Stamp Vernon Box 75010 HH Oklahoma ed 13101 30 00 HUNDRED Stuffing Our Gircutmrs Tito Stamped Addressed Envelopes Immediate Earnings Beginners Kit 2 00 COLOSSI 1433 61 Street DC 2 Brooklyn NY 11219 NEW Valuable Informative Manual on Mail order Learn How to Setup Run your busi ness Facts free Frontierico 154 D1 Sprenger Butla o NY 14211 100045 PROFIT Bronzing Baby Shoes Free Litera ture NBC DG Gower MO 64454 IMPATIENT Produce Oil Portraits instantly De tails 25e refundable Jiffyportraits 2830 BP Gaffey San Pedro CA 90131 MAKE 1 000 A WEEK CAMPING No Capitul Land Selling or Experience needed Details 254 Write Camping Dept 602 Box 1616 Torrance CA 90505 250 WEEKLY Stuff our sales letter into stamped addressed envelope Immediate Income Details 25e Sunshine Box 115 S711 NYC 10003 25 DAILY POSSIBLE dude VECES Free dee tails Service Box 715D Lynbrook New York 11563 OWN Your Own Business Correspondence C ub Magazine Information Details 256 Destiny Box 5637
95. Y possible mailing letters Free details Brown E Star Rt 205 Nowata OK 74048 UNLIMITED EARNINGS not a scheme Producti sample and details 2 00 Refundable Narwid Elec tronics 61 Bellot Rd Ringwood NJ 07456 HOMEWORKERS Stuff envelopes Make big money Free details Cypress 439 Cypress Dr Lake 850 MONTHLY sparetime homework Detaiis free Guizar 690 Neckel Imperial CA 92251 PLAN reveals secrets homeworkers Rohrer Box 2594 Hyattsville MD 20784 YOU can make stuffing envelopes Free de tails Mahoney 317 E Navilla Covina CA 1723 200 WEEK working evenings at home Write Fiesta Box 2882 Springfield IL 62708 NEW easy homework plan Free details Endevco 129 S Columbo Tustin CA 92680 AGENTS WANTED GET cash commission with each order from friends neighbors for America s finest shoes Easy Profitable No experience needed Selling outfit free Mason Shoes K 256 Chippewa Falls WI 54729 AUTO PARTS amp ACCESSORIES NEW UNIQUE THEFT PROOF CAR KIT 4 00 BEECO 280 South Main St Centerville OH 45459 BATTERIES GENERATORS REPAIR electric motors Automobile generators Alternators Batteries Modelec Box 7266 Kansas City MO 64113 BIG MAIL RECEIVE mail galore National listing 1 00 Sullins Box 1313 EE Brunswick GA 31520 BLUEPRINTS PATTERNS amp PLANS NEW CRAIT PRINT CATALOG Choose fron
96. ac Asimov The Science Fiction magazine you ve been waiting for hy the most respected and prolific writer in the field Published quarterly The most and best in SF in every issue you could expect And you d expect that from Asimov TUTTLE TTT CETT EIEEEI TITELE OTTEET ESSE SESE ST TO ISAAC ASIMOV S SCIENCE FICTION MAGAZINE EE M A 7 Box 1855 GPO New York NY 10001 enclose 5 40 includes shipping and postage for 4 issues of ISAAC ASIMOV S SCIENCE FICTION MAGAZINE Name please print Acdress City State Zip ELEMENTARY ELECTRONICS March April 1977 two frequencies 12080 and another varying between 13200 and 13300 kHz There is no doubt that the studio is at Caracas and one reesonably can assume that the transmitter site is within radio link or landline distance of the Vene zuelan capitol But that could mean anything from a nearby suburb to some remote spot a couple hundred miles away On one occasion this author heard R Euzkadi cross modulating with an other broadcast station It has been sugegsted by members of the North American SW Association that the sta tion uses utility eg telephone trans mitters If the latter assumption is cor rect R Euzkadi s transmitter site is certainly an interesting mixture 25 amp 31 Meters Before concluding this roundup of Colombian and Vene zuelan DX t should be noted that R Nacional de Colombia operates trans mitters somewhat erratic
97. ailbox Send sase or rush 10 and get rich quicker Tina Heckaman Rt 2 Box 726 Hamshire TX 77622 GUARANTEED stuffing letters Free details Stanvil 1830 Yates Bronx NY 10461 MUSIC amp MUSICAL INSTRUMENTS INTERNATIONAL Catalog valuable to makers re pairers string instruments Biggest variety parts accessories all imported woods bows kits Send 254 and this ad for catalog price list We ll include certificate worth 1 25 credit on your first order of at least 10 International Violin Company Dept YS 4026 W Belvedere Ave Baltimore MD 21215 OF INTEREST TO WOMEN 3000 00 MONTHLY Immediate Income Stuff en velopes at home Information send self addressed stamped envelope Cottage Box 730AFB Baldwin Park CA 91706 AMAZING Find Collection 100 Year Old Pioneer Recipes Write Mormans 3975 Rawhide SLC UT CAIN PERSONAL JAPANESE introductions Girls photographs de scriptions brochure detarls 1 00 INTER PACIFIC Box 304 SC Birmingham MI 48012 SINGLE Widowed Divorced Nationwide introduc tions Identity Box 315 DC Royal Oak MI 48068 x 5 DATE WITH DIGNITY Professional Matching Drawer 6765 Fort Worth 76115 817 921 0281 Anytime JAPANESE Girls Make Wonderful Wives We have large number of listings Many interested in mar riage Only 1 00 brings application photos names descriptions questionnaire Etc Japan International Box 118
98. aker unit you can if necessary file a Ye inch wide slot in the edge of the grille and the retaining ring to clear the hook up wire where it passes a TS ELEMENTARY ELECTRONICS INDEX TO ADVERTISERS READERS PAGE SERVICE NO ADVERTISER NUMBER AMC Sales 90 5 AP Products 24 39 Anixter Mark 91 6 Avanti Research 31 36 B amp K Precision L3 Barta c 90 Cleveland Institute of Elect 98 CV II 24 Cobra Div Dynascan 5 16 Continental Specialties 17 22 Cush Craft 20 21 E L Instruments 22 7 Edmund Scientific 19 2 Fico Electronics 26 Gilfer 90 8 Grantham Schools 21 Heath 53 54 Herman Co 90 int l Correspondence School CV 11 3 9 Int Crystal 20 33 E F Johnson 30 38 Kedman Tobis 33 11 Kester Solder 24 Kuhn Electronics 90 McGee Radio 90 35 Midland Electronics 8 9 28 Mtn West Alarm 30 Nat Radio Institute 34 37 Nat Technical Schools 62 65 23 New Tronics 12 18 19 20 OK Machine amp Tools Co 25 27 29 PPG Electrnoics 90 41 Pacer Antenna Div Progress nc 16 Peninsula Mktg 32 26 Polypaks 95 13 Progressive Edu Kits 11 32 Radio Shack 23 28 38 CV IV 25 Shakespeare Antennas 7 17 Sparkomatic 14 15 14 Tab Books 6 29 Turner Div Conrac Corp 10 15 Vernitron 18 Vintage Radio s oo 94 Driver Units For best results 1 sug gest you use the Radio Shack number 40 1292 acoustic suspension Speaker driver which costs just under 17 You can a
99. alling Car 54 Car 54 Clean your windows someone is stealing your hubcaps 24 ELEMENTARY ELECTRONICS March April 1977 VP ERIE ACT MOTORIZED by FAMOUS ARCHER Z Flip its switch and the Archer electric antenna d extends to its full 33 length and turns your CB radio on Flip again and it retracts into the fender and turns your radio off Nobody will know you ve got ears its Archer s automatic answer to CB rip offs A top performer that ends the bother of removing your antenna Adjustable SWR Center loading coil excellent for mobile use Quality materials and workmanship Installation hardware and instructions included Our disappearing act is another reason why a million CB ers will choose Radio Shack s Archer brand this year Get 21 970 and you ll have something to hide and nothing to lose Only 59 95 now you see it now you dont dip f LEADING THE WAY IN QUALITY CB SINCE 1960 Just Say Charge It Rad Io Shaek at most stores Price may vary at individual stores and dealers A TANDY COMPANY FORT WORTH TEXAS 76107 prices and products may vary in Canada 5000 LOCATIONS IN NINE COUNTRIES ELEMENTARY ELECTRONICS March April 1977 23 NEWSC AN oT formation for his trip For the first leg the meteorological and aircraft performance information he enters may be as follows 12 E magnetic compass variation 200 wind direction 28 knots wind velocity 115 knots true ai
100. ally on 11795 and 9628 KHz On that same 31 Meter international band a few Venezuelan qe TWEEN Things You Should Know Continued from page 58 tions to 27 415 MHz and above In Between Channels The amount of unauthorized operation on non existent CB channels is not limited to those frequencies outside of the band edges for there is a rich harvest of frequencies which lie between the regular CB chan nels For instance the Class C radio control channels 26 995 27 045 27 095 27 145 and 27 155 MHz are in relatively heavy use by CBers who are skirting Part 95 Many a R C model crashed because of this illegal hobbying The Advantages You may ask Why are people going to so much trouble to operate on these channels Good question Primarily for two reasons they are not nearly as crowded as the authorized channels and the folks who operate them are primarily interested in com municating in a manner which existed on the authorized CB channels many years ago but which seems impossible today because of the fact that most CB ers are only interested in asking for radio checks and time checks On these other frequencies it is not uncommon to hear cross country round table dis cussions involving numerous stations who discuss any number of topics from radio to sports It s a rather unhurried and casual form of CB radio although plainly against this are many CB rules and regulations as set forth by the FCC Yes every no
101. and Warming Up Heading South is WFYR Family Radio the California based U S shortwave operation Though this station with religious orientation is headquartered on the west coast its shortwave transmitters have been located at Scituate MA across the continent Not long ago WFYR an nounced it had been granted permission by the Federal Communications Commis sion tO move its transmitters from Mas sachusetts to Okeechobee FL It is hoped that the southern move will improve short wave reception of the station in South America For now here are some times and fre quencies to check for WYFR s programs 0000 GMT 6 155 KHz 0400 GMT 6 155 kHz 1800 GMT 17 845 kHz 1900 GMT 11 805 kHz and 2000 GMT 11 805 kHz Backtalk This is the spot in each DX Central Reporting where you have your say Comments questions observations about the world of DXing and your parti cipation in it are always welcome Send your letters to me Don Jensen DX Cen tral ELEMENTARY ELECTRONICS 229 Park Avenue South New York NY 10003 PH be looking forward to hearing from you And if you ve got a spare photograph of you and your shack that s DX talk for your listening setup send it along In clude identification of any equipment shown in the photo If you like the idea il try to feature some of your photo graphs in DX Central Reporting from time to time To start things off a pair of questions from 18 year old Wayne Davis of Kansas Ci
102. and Venezuelan tar gets to shoot for The most often re ported Venezuelan MW station is Radiotimpo 1200 kHz at Caracas which may be the most widely heard 10 KW BCB transmitter in the world It has been logged as far north as Canada sometimes a few minutes be fore sunset at Caracas The chief source of interference in most parts of North America is not 50 KW WOAI at San Antonio Texas but A Almirante at Riohacha Colombia If you live too close to San Antonio to log DX on 1200 kHz there are other promising frequencies to monitor Any time an ionsopheric disturbance knocks out signals from KMOX St Louis on 1120 watch for Ondas del Mar from Maracaibo There is R Caracas which has a relatively new 50 KW transmitter on 750 kHz and seems to be especially well heard in western North America The first Colombian station men za 7 E I Kw v M 2 YVLK YVAK YVLL F A A 4910 K 1 970 X 99 M ener Onde arte Dads Carts Frag Mod ow ES rm mme cud oe ee CAXACAS VENEZUELA f A PA i KM 2 7 y Mem i STUDIOS Hinin 5 y 2 SOS EL SEN TIS FONOS 421457 412041 4727655 E ys y A p n A APARTADO 9DSTe4 2516 f fx b 7 1 AVENIDA LA Ped L PaRatso _ anid stews LA Teu t ptit 4DIO CA UPAM O I l EMISORAS OF CIRCUITO ADIO BARCELONA i H aDIO PUNTO F JO YUN OK i Ss E A a A V E i j For beginning DXers the QSL card shown here is one of the easiest to
103. and every time there is a skip opening it buzzes away with wall to wall stations from one end of the country to another all using old CB rigs tied to communications receivers CB ers have also found that many of the new Phase Lock Loop PLL rigs are inexpensively modified by under ground technicians to open up a whole new world of unauthorized channels Months before the 17 new CB channels were authorized CB ers with PLL type rigs were having these modifications done One 23 channel PLL rig we saw was quickly fixed up to operate on 44 channels with the lowest frequency be ing 26 865 MHz and the highest 27 425 MHz far past the band edges author ized There were a few channels miss ing in between due to the nature of the PLL circuit in that particular unit Of course ham radio transceivers are eagerly sought after by many CBrers who have found that ham transceivers such as the Yaesu FT 10I E the Tempo I and various Kenwoods Swans Drakes and the new mini rig the Kachina all function remarkably a CT a ng pas y gr an T a As g e ge gut day jan gna Me VT e ee o o 0 7 0 5 7 4 Q onm iut SP e tas Dm mE Ne PQS ss SIDEBANDERS SERVICE BUREAU CERTIFICATE OF AWARD This Cerificate has been awarded to 3 vw e T gius well on CB frequencies and other fre quencies in their general area too Not only that some of them will put out a 250 watt PEP sideba
104. aries e Four piece construction for easy handling amp shipping by UPS Eliminates noisy precipitation static Improves signal to noise ratio Affords up to 20 db operating gain Increases receiver sensitivity Extends intelligible coverage Easiest to install design No unsightly ground radials The Mark AMB 2 will step up the efficiency of any CB base station The reactive tuner eliminates matching problems reduces the effects of nearby objects and gives the owest possible VSWR all with one simple adjustment That s truly tuneable and that s just one reason why this is the most advanced base station antenna ever For more information and a free copy of The CB Amateur Two Way Antennas amp Accessories Catalog send the coupon today You bet I d like a free catalog q Name i Title Company Address City State Zip NUIT DC i 3 s NEM j Manufacturers of a Full line of Point to Point Antennas Microwave Two Way Amateur CB 5439 W Fargo Skokie IL 60076 312 675 1500 Made in U S A Visit us at booth 394 amp 395 during the PC 77 Showl CIRCLE 39 ON READER SERVICE COUPON 91 AMATEUR RADIO HAM LICENSE NEw METHOD OF LEARNING CODE USEO BY PEOPLE FROM 10 THRU 65 YEARS PLENTY OF PRACTICE MA TERIAL NOVICE LICENSE TRAINING SCHEDULE ALL REFERENCE MATERIALS CHECKING SHEETS FOR ACCU E RACY COMPLETE STANDARD 2 TRACK MONAURAL a TTES PROVIDE 60 MINUTES EACH OF SCIENTIFICALLY PREP
105. asurements in Lis sajous figures are shown below QUESTION Q11 If the standard frequency is 180 cps what is the frequency of the unknown in each of the above Lissajous patterns ANSWERS A11 Values of unknown frequencies are A 900 Hz vertical horizontal ratio is 5 1 B 20 Hz 1 9 ratio i C 108 Hz 3 5 ratio D 150 Hz 5 6 ratio WHAT YOU HAVE LEARNED 1 An oscilloscope is a test instrument which displays waveforms It reproduces the amplitude and time characteristics of a waveform This permits check 87 figure is the pattern obtained when AC signals are ap plied simultaneously to both sets of deflection plates The following procedures are typical of most oscillo scopes Phase Measurement When you are measuring the phase difference between two signals one signal is applied to the vertical and the other to the horizontal Lissajous Figure Waveform In Phase input Turn the sweep off so that there will be no saw tooth voltage to interefere with the signal in the hori zontal channel For greatest accuracy the amplitudes of the two signals should be equal Adjust the gain controls to obtain a pattern that is a high as it is wide When measuring for phase difference the two signals must of course be the same frequency QUESTIONS Q4 If test points H G and F in the block diagram provide improper waveforms and test point E shows the correct waveform in which circuit is the trouble loca
106. atio of 1 5 1 or less and is fully weatherproof For ELEMENTARY ELECTRONICS March April 1977 CIRCLE 53 ON READER SERVICE COUPON further information on the Model 17610 pre assembled trunk lip mount antenna and the complete line of Antenna Incorporated Products write to Antenna Incorporated 23850 Commerce Park Road Cleveland OH 44122 Three Power Mikes Mura has a series of three CB microphones incorporating a unique patented circuit that conditions voice signals for greater trans mission clarity and power The new micro phones offer a potential increase of 16 dB fully modulated voltage gain and an average increase of 4 dB in effective RF transceiver output power These microphones incorporate Peak Redistribution Modulation PRM cir cuitry which electronically prevents clipping of voice signal allowing maximum modula ted power output from limited level ampli fiers The Mura Model PRX 100 is a power microphone offering a variable gain setting controlled by a slide switch on the micro phone and sells for 39 95 including battery The Mura Model PRX 200 power microphone CIRCLE 37 ON READER SERVICE COUPON E A AIRA PRx 100 f offers the advantages of the peak redistribu tion modulation circuitry for maximum audio clarity and power and the flexibility pro vided by three separate gain settings 12 dB 14 dB or 16 dB It sells for 34 95 The Mura Model PRX 300 is a distinctively styled base station mic
107. ation ELEMENTARY ELECTRONICS March April 1977 RR Multicycle Displays I5 209 CYCLES EXPANDED QUESTION Q3 To observe three cycles of a 45 000 Hz signal to what setting s would you adjust which controls ANSWER A3 Set the Coarse Freq control to 15 kHz and adjust the Vernier control for a steady display When there are too many cycles for easy viewing expanding the presentation with the horizontal gain control will separate the cycles for better viewing Reading Waveforms Signals waveforms are modified or changed as they pass from stage to stage in a piece of electronic equipment until the signal from the final stage contains the desired characteristics With an oscilloscope you can test the signals at each stage in a piece of equip ment to determine whether the circuits are operating properly and or which one might be the cause of a trouble Block Diagram With Waveforms VERTICAL DEFLECTION AMPLIFIER TOV DAT HORIZONTAL DEFLECTION AMPLIFIER fi P T 30 000u SEC 3 3V K T 30 000uSEC The above block diagram is representative of a servicing block diagram for an oscilloscope The let ters in circles identify important test points The wave forms beside them show the shape voltage and time duration where applicable that should be observed at these points Arrows on block connecting lines show the direction of signal flow This diagram would be used when
108. ation with a Royce 1 650 CB rig on top of the Kriket For more information circle No 74 on the Reader Service coupon plugs into the external speaker jack at the rear of the transceiver The easiest and quickest way to pro vide power is to use plug that goes into the car cigarette lighter socket Just cut the cord so that its long enough to reach to the rear of the trans ceiver but so that there s no extra slack to tangle with your accelerator foot And forget about messing around with a soldering iron connect the power lead to the section coming from the CB unit with no solder crimp on con nectors Thats all there is to it But do re member to attach the antenna cable to the CB rig before placing the unit on the hump because you could blow some transistors in your transceiver if you attempt to transmit with the antenna disconnected To remove the CB rig and speaker mount pull the power plug from the lighter socket and disconnect the an tenna lead What could be easier or faster You can now lift the entire unit olt the hump and put it in a safe place If you must park your car outside every night you ll sleep better knowing that vour CB is safe inside your home And you will enjoy your next movie or whatever a great deal more if you know that your Kriket CB unit is out of sight in the car trunk For additional information circle No 74 on the Reader Service coupon m ELEMENTARY ELECTRONICS March April
109. ationally speaking This serv ice probably never has been heard in North America though Radio Thailand can be heard Stateside mornings when it Oslensibly is aimed at other audiences Inscrutable Frequency selection is a more compli cated business for the shortwave broad caster While some international broad casting Stations change channels more fre quently most of the big boys alter their frequencies four times a year They divide their broadcasting year into four sea sons These are the two long seasons the J schedule May June July and August and the D schedule November De cember January and February and the two short or transition seasons the M schedule March and April and the S schedule September and October The frequency choices are based on propagational considerations which change season by season based on natural phe nomena such as the angle of the sun the number of hours of solar radiation and so forth SWLs of course are familiar with the vexing problem of having two sometimes more major stations plopped down on the same or adjoining frequencies causing a headache of mutual interference With all the stations vying for channels during the optimum evening hours in North America what is surprising is that there isn t more co channel interference than there is Attempting to co ordinate this com plex business of selecting frequencies is the International Frequency Regis
110. ave technical tips radio col lector club news and other items of interest So long for now Li ELEMENTARY ELECTRONICS March April 1977 C AL Base Beam Shakespeare it seems has the first and only fiberglass base station directional beam an tenna A totally new design that s been thoroughly tested mechanically and elec trically to give top CB communications The gleaming white fiberglass construction re DL etr tm p ilf rr NE A CIRCLE 43 ON READER SERVICE COUPON sists even the harshest environmental con ditions And fiberglass elements far exceed metal in reducing precipitation static Shake speare s MegaBeam Style 4104 base sta tion directional antenna provides low VSWR over the entire 40 channels For complete technical facts write to Shakespeare Com pany Antenna Group P O Box 246 Colum bia SC 29202 In Canada Len Finkler Ltd 25 Toro Road Downsview Ontario Canada M3J 2A6 Mobile Antenna Lock Tenna loc provides anti theft protection for CB mobile antennas Tenna loc is available in a choice of models to fit most antenna styles domestic and imported and it allows CB mobile antennas to remain intact and in place year round and in all kinds of weather Tenna loc retails for less than 12 NEW PRODUCTS e e puts together in one neat package some of the newest CB rigs exi T antennas and accessories for you to use in CB contacts this year 7 and features a turn proof locking stud
111. ayer when you park The slide mount has two pieces One attaches to the dash the other attaches to the player as shown in the photographs Each sec tion has sliding contact terminals which feed the power ground and speaker connections to the player You will find the part of the mount that gets assembled to the player has terminals with attached wires that are supposed to be spliced into the player s output wires You get a neater installa tion and eliminate the chance of the wires getting snagged if you unsolder the terminal wires and then solder the players wires directly to the mount s terminals Make certain the mount s ground wire is secured under one of the screws or nuts that fastens the mount to the tape player or the tape player bracket for this wire supplies both the power supply ground and com mon speaker connection If necessary tape the wires to the mount to prevent them from snagging when the mount is inserted under the dash The part of the mount secured to the dash needs only two screws and 8 or Continued on page 94 Photo One shows the cassette player with the lower half of the slide mount on top of it Slide mount attaches to player s bracket Two is rear view of player show ing sliding terminals for connection to speakers and car battery Three shows the top half of slide mount screwed under dash Four is the spliced red battery power lead Make it short Five shows the
112. ays when CB transmitters didn t have 100 percent modulation limiting or sufficient microphone preampliti cation Someone the exact name slips my mind built an accessory preampli fier with about 6 dB compression there by providing a boost to both the aver age voice power and the lower level speech sounds Someone else added peak limiting to prevent modulating more than 100 percent modulation with its resultant distortion and sideband splatter and then the whole thing was wrapped up with a little extra gain and a level control so the user could adjust her or his modulation as close as possi ble to 85 100 percent Some early compressors even had built in meters to insure optimum adjustment These compressors did wonders for Two high quality CB power mikes from Shure Bros One on right is noise cancelling mobile mike responds only to sounds within an inch or two Base unit mike left has built in amp which works best set at minimum gain Whole base is PTT switch CB After all they simply provided the compression that already existed in just about every other type of commu nications transmitter Then so called power mikes came along These were actually nothing more than an inexpensive sometimes high quality microphone driving a high gain preamplifier By the time the signal gets into the transceiver it either overdrives the transceivers input tran sistor causing signal distortion or de Fig
113. book every collector will want for his own library Seattle Collectors If you live in or near Seattle Washington you will be happy to know that an antique radio collecting club has been formed there Antique Wireless Association AWA meet ing had 400 collectors in attendance Here are a few of the goodies at the flea market Alan Douglas left talking about his collec tion of old medical machines with AWA president Charles Brelsford ELEMENTARY ELECTRONICS March April 1977 The first meeting was held at the home of Lee Williams with five persons pres ent If you are interested in joining you can write Woodrow F Wells 8307 NW 22nd Avenue Seattle WA 98117 or call him at 789 2370 If you live near Opelika Alabama or plan to vacation there next summer you will want to visit the world s largest privately owned collection of battery operated radios and phonographs It s owned by J Herbert Orr a pioneer in magnetic tape recording Mr Orr s col lection includes both cylinder and disc phonographs and they all work The radios have all been restored to like new condition and there are so many that they are housed in several buildings One of his major developments just patented ts a player piano that uses computer technology and magnetic tape to create the player piano effect A mini computer attached to the piano records the movement of the keys ped als and hammers on cassette tape After recording a
114. builds them tougher There are 43 models for all kir ds of base and mobile installations Ask anybody who has been around CB for awhile They kncw us Wherever CB is sold Turner The talk of the road TUHNEH MICROPHONES ANTENNAS CONRAC CORPO ATION 7 6 Oakland Road N E Cedar Rapids lowa 52402 CIRCLE 29 ON READER SERVICE COUPON Hey Look Me Over Continued from page 6 gered by current flow caused when any light in the automobile is turned on by opening any door If equipped with a light the vehicle trunk or hood is also protected by the system The System s circuitry beeps the car horn for 212 minutes to scare off would be thieves The system then shuts down and auto matically rearms itself Excessive battery drain or horn damage associated with CIRCLE 52 ON READER SERVICE COUPON continuous horn operation is avoided and the system shutdown feature also eliminates the nuisance problem of ac cidently tripped alarms For further in formation on this mobile CB security system available nationwide at CB and automotive distributors and selling for only 17 95 contact Harcor laterna tional Inc 744 Algonquin Road Dept PR Arlington Heights IL 60005 TV Remote Control A remote control capable of selecting all TV channels UHF as well as VHF has been developed by Jerrold Electronics Corporation a subsidiary of the world wide General Instrument Corporation De signated the Model TRC 82 it provides
115. c equip ment with a minimum of service literature and without any service data This occurs often in troubleshooting situations Hand book of Basic Electronic Troubleshooting by John D Lenk assumes that the reader is familiar with basic electronics but has no special knowledge of test equipment and no practical experience in trouble shooting As such it is ideal for the be ginner in the field However the basic techniques described apply to all types of electronics therefore the handbook is help ful to advanced technicians and engineers as well The use of test equipment during Hard cover 239 pages 15 95 SHO OMIN CE troubleshooting is described in detail in cluding how to connect test equipment to circuits and how to make point to point voltage resistance continuity checks of basic circuits Alignment and adjustment procedures are described assuring that the equipment is restored to normal opera tion in peak condition Published by Prentice Hall Inc Englewood Cliffs NJ 07632 CB Projcts You can t build a CB transmitter or transceiver because the law says you can t But CB projects that are extremely useful plus inexpensive to all your own Yau don tneed one The AntennaMentishere A 4dBgainbase station antenna only 64 tall Lightweight portable tunable for minimum SWR transmits across 23 or 40 channels Free standing for use on desk top patio house camper beach anywhere your radio can
116. check out TI and T2 to see if they have AC output voltage coming from their secondaries when dis connected from the circuit If the clock portion works but the buzzer will not sound check E3 to see if the voltage at PM INDICATOR ALARM OIsPLAY SNOO2 SLEEP SECONOS DISPLAY ALARM ALARM ON INDICATOR Additional optional functions diagrammed at left in schematic are shown above con nected to the module that point goes high relative to E7 when the alarm is supposed to go off Do not be tricked by the AM PM capability of this clock when checking the alarm If your clock is set to go off at 6 00 AM do not expect it to go off at 6 00 PM when testing it Pay attention to the litte AM PM dot in the upper left corner National makes eight different modules in the MA 1002A through E series Be sure you use only the one with A when you re building this project 61 a Mod X Clock PUSH BUTTONS I 2 3 TI a A b B PRI SEC TOP view VIEW 25V 300 MA 6V 300 MA a TI A 470a 300a IO WATT 1O WATT b 25v B FI 120 VAC b ev B PARTS LIST FOR MOD X Ci 100 uF 20 VDC or better electrolytic capacitor Radio Shack 272 1016 or equiv D1 1 A 200 V diode Radio Shack 276 1102 or equiv F1 A 125 VAC fuse Radio Shack 270 1270 or equiv M1 Clock module National Semiconductor MA 1002A Digi Key Corp See below for address R1 470 ohm 10 watt resistor
117. colors missing or otherwise untrue in color One com pany advises Fluorescent lighting is projection TV s worst enemv Projection TV points up the vast variations in basic picture quality of TV commercials If a commercial is poorly made its defects will be mag nified literally and exaggerated Poor color rendition in the original commercial may turn out to be hor rendous on a giant screen such as that of the Advent Vidcobeam Poorly delineated details in a TV commercial shadows for example may wash out totally in a projected picture Clothing patterns may van ish faces of old people will be wrinkle free etc What s Available Home video projection systems come in a variety of models You can buy them in one 42 L Advent s Videobeam system comes in two versions major difference is in size of projected jit I A E S i ee L5 P k picture Model 750 priced at 2 495 has six foot diagonal screen Model 1000 costs 4 000 piece two piece or three piece form The one piece models contain every thing in one large housing some times with the screen a fold down or fold away proposition The two piece outfits house the TV and pro jection equipment in one housing the screen in another The three piece ensembles consist of TV at tachable projection lens or lens mirror assembly and separate screen Most commonly used are Kodak Ektalite screens because of their high reflective
118. comme Here s your chance to get start and save in the process Buy Dealer inquiries invited crete components insert di rectly without adapters And all interconnections are made with 20 to 26 gage solid con ductor wire Get started now E amp L sol derless bread boarding sock ets are avail able through local participat ing computer stores These stores also carry E amp L s full line of breadboarding and micro W computer equipment as well as our line of BUGBOOKSS Stop in today and start going sol derless CIRCLE 21 ON READER SERVICE COUPON 22 included in the library including one for use when there are winds aloft one with a verification routine and another for long range flights Other programs are included for rhumb line navigation dead reckoning and great circle flying The key element in this system ts that the pilot can store information ahead of time on one of his magnetic cards During the flight he only needs to key in a reference number for a waypoint rather than its detailed coordinates This prevents entry errors during the flight Some of the other programs in the library include those for predicting freezing and lowest usable flight levels atmospheric conditions mach number true air speed true air temperatures density and line of sight altitude and DME speed correction And the price is right The SR 52 calculator has a suggested retail price of 299 95 The
119. computer aoes far beyond any logic trainer in preparing you to become a computer or digital technician With the IC s in its new Memory Kit you get the only home training in machine language programming experience essential to trouble shooting digital computers And the NRI programmable computer is just one of ten kits you receive including a TVOM and NRI s exclusive electronics lab It s the quickest and best way to learn digital logic and computer operation You pay less for NRI training and you get more for your money NRI employs no salesmen pays no commissions We pass the savings on to you in reduced tuitions and extras in the way of professional equipment testing instruments etc You can pay more but you can t get better training More than one million students have enrolled with NRI in 62 years Mail the insert card and discover for yourself why NRI is the recognized leader in home training No salesman will call Do it today and get started on that new career APPROVED UNDER GI BiLL if taken for career purposes Check box on card fer details NRI NRI SCHOOLS w McGraw Hill Continuing Education Center e 3939 Wisconsin Avenue Hi E v D C 20046 6 0 37 m Learn to service Communications CB equipment at home with NRI S COMPLETE COMMUNICATIONS COURSE Learn design installation and maintenance of s commercial amateur or CB communications equipment The field of communications is bur
120. costs about 35 It is essentially what ham operators used to call a rubber crystal With a slider you can move right off any CB channel to any frequency you want as far away as 5 10 20 er more kHz from the authorized CB channel A VFO is an external device which plugs into the oscillator circuitry of a CB rig giving the operator the chance to tune a CB rig to any desired fre quency within the range of the VFO The operator then simply dials the fre quency wanted the way an AM or FM broadcast receiver would be tuned in on a station CBers long ago learned the trick of taking discrete receiver crystals those crystals designed for older CB rigs which didn t have synthesized oscillator circuits and switching them into their discrete transmitter circuits Few mod ern day CB rigs are designed for such crystals but all older sets used them and older CB rigs are still available at give away prices The crystals for re ceiving are 455 kHz lower than the frequency of the CB channels So if a discrete receiver crystal for CB Chan nel 23 27 255 MHz was plugged into Here is the Sidebanders multi purpose achievement award Text gives details You decide value 58 THINGS YOU PROBABLY DON T KNOW ABOUT CB RADIO AND SHOULDNT by Wally Unit944 944 the transmitter the CB er ends up with a transmitting frequency 455 kHz below the channel or 26 800 MHz As it turns out 26 800 MHz is a very busy fre quency
121. d BARREL KIT 5 SCRS TRIACS with utton oO Send for FREE T itt MINIMUM ORDER 6 00 SPRING CATALOG 05 i 1 98 Haw factory Q L i PA K S stock All the 10 amp types Cat No 2L 2419 Untested P O BOX 942D LYNNFIELD MASS 01940 CIRCLE 26 ON READER SERVICE COUPON 95 tapping screws will bite into the mason ite nicely Don t screw them tight enough to strip the holes If you do by mistake you can always rotate the top assembly metal ring a few degrees and start over on the holes for the self tappers Now drill a hole for the speaker wire through the side of the plastic cover right at the very top Just under the re taining ring Angle this hole so it comes out inside the diameter of the plastic cover near the speaker but outside the speaker frame It may be easier to drill two holes one from the inside of the Masonite side near the speaker and one from the outside of the plastic Be sure to use a drill no larger than absolutely necessary to pass the speaker wire through Install the top section of the food container over the neck of the enclo sure and screw the cover on tight Run about 6 inch length of no 24 speaker wire through the hole and solder to the speaker terminals Rein stall the speaker unit and dope the hook up wire around the hole at the under side of the stiffening flange with plastic cement to insure air tightness Before you install the grille over the spe
122. d State OC Power Supplies 196p 15111 6 95 O Optoelectronics Guidebk with tested projects 196 p 5 95 C Transistor Ignition Systems 252 p 1621 5 95 OTY Lighting Handbook 228 p 261 il 12 95 CHow lo Repair Home Kitchen Appliances 294 p 20511 5 95 O Fun With Electronics 140 p 88 il 3 95 OTalk Back TV Two Way Cable Television 238p 6411 5 95 C Understanding Use Modern Signal Generators 294 p 6 95 1106 Easy Electronic Projs Beyond Transistors 224 p 5 95 CJUsing Modern Electr Serv Test Egpt 252 p 177 il 5 95 OMathematics Unraveied Commonsense Approach 6 95 C Master Tube Substitution Handbook 322 p 548 Il 4 95 O Modern Guide to Digital Logic 294 p 222 il 6 935 COVHF UHF Fire Police Ham Scanners Man 250p 114il 6 95 OOP AMP Circuit Design amp Applications 280 p 239 il 6 95 OC Master Hdbk of Digital Logic Appl 392 p 287 il 7 95 C CET License Handbook 2nd ed 448 p 381 il 8 95 OThe Electronic Musical insir Manual 210 p 3851 6 95 C Microprocessor Microprograming Hdbk 294 p 176 il 6 95 O Sourcebook of Electronic em Circuits 168p 101 il 4 95 O Build Your Own Working Robot 238 p 83 il 5 95 CJCBer s Handybook of Simple Hobby Projs 168p 114i 3 95 Fire amp Thett Security Systems 2nd ed 192 p 1141l 5 95 CO How to Ror Home Laundry Appliances 280 p 137 i 5 95 CJPiloting Navigation amp Pocket Calculator 392 p 233i 8 95 aiiiisuu iif PLI T aa LSE CL
123. d fire alarm THE WIDE WORLD OF CB RADIO Kathi Rides a Mile for a Kamel she shows how to install on car hump for CB super safety Things You Never Knew About CB Radio and that you probably shouldn t CB New Products new CB sets and accessories that will keep you 10 4ing CB New Products more goodies for Good Buddies Kathi s CB Carousel a l about powermikes CB Whine eliminate that interference for better CB reception PATHS TO BETTER SOUND It s a Cookie Jar compact speaker system you build in glass Put Your Cassette on Wheels use car speakers for low cost installation THE WORLD OF WIRELESS Power Antique Radios from an AC Battery build modern B and A batteries with Jim Fred Antique Radio Corner news of collectors meetings and some headphone help SHORTWAVE LISTENING DX Central Reporting Don Jensen s regular column on getting the most out of the ether DXing Colombia and Venezuela another Stanbury guide Latin American DX on 49 and 60 meters CONSUMER INFO FROM OUR LAB e e Assembles the Heath AS 1344 2 Way Column Speaker Kit e e Checks Out the B amp K 2040 CB Servicemaster OUR REGULAR DEPARTMENTS Hey Look Me Over new electronic products Bookmark by Bookworm Newscan what s happening in electronics Ask Hank He Knows Hank s usual with a correction for AC Tester constructors Computer Readout p aying games with the KIM 1 microcomputer Reader Service Coupons Basic Course h
124. e President and Treasurer Victor C Stabile KBP0681 ELEMENTARY ELECTRONICS is pub lished bi monthly by Davis Publica tions Inc Editorial and Executive offices 229 Park Ave So New York NY 10003 all subscription orders and mail regarding subscriptions should be sent to P O Box 2600 Greenwich CT 06830 One year subscription six is sues 6 50 two year subscription 12 issues 13 00 three year subscrip tion 18 issues 19 00 and four year subscription 24 issues 25 00 Add 67 cents postage for each year for U S possessions and Canada 1 34 each year all other countries For change of address please advise 4 to 6 weeks before moving Send us your current mailing label with new address Adver tising offices New York 229 Park Avenue South 212 673 1300 Chicago 520 N Michigan Ave 312 527 0330 Los Angeles J E Publishers Rep Co 8732 Sunset Blvd 213 659 3810 Second class postage paid at New York NY and at additional mailing office Copyright 1977 by Davis Publications Inc What would a second Job mean to vou A few grubby dollars and a life that s an endess grind You ll hardly ever see vour familv You won t have time for friends or fun Your wife will wonder what hap penec to the husband she used to have Yov ll spend your days off sleeping t just isn t worth it And it doesn t have to be that way Millions of men make a good living with one job Mil lions of men actually
125. e VALUABLE DISCOUNT CARD e CERTIFICATE OF MERIT e TESTER INSTRUCTION MANUAL e HIGH FIDELITY GUIDE e QUIZZES e TELEVISION BOOK e RADIO TROUBLE SHOOTING BOOK MEMBERSHIP IN RADIO TV CLUB CONSULTATION SERVICE e FCC AMATEUR LICENSE TRAINING PRINTED CIRCUITRY SERVICING LESSONS You will learn trouble shooting and Servicing in a progressive manner You will Practice repairs on the sets that you construct You will learn symptoms and causes of trouble in home portable and car radios You will learn how to use the professionai Signai Tracer the unique Signal Injector and the dynamic Radio amp Electronics Tester While you are learning in this practical way you will be able to do many a repair job for your friends and neighbors and charge fees which wil far exceed the price of the Edu Kit Our Consultation Service will help you with any technical Prob lems you may have FROM OUR MAIL BAG J Stataitis of 25 Poplar PI Water bury Conn writes l have repaired several sets for my friends and made money The Edu Kit paid for itself i was ready to spend 240 for a Course but found your ad and sent for your Kit Ben Valerio P O Box 21 Magna Utah The Edu Kits are wonderful Here am sending you the questions and also the answers for them 1 have been in Radio for the last seven years but like to work with Radio Kits and like to build Radio Testing Equipment en joyed every minute
126. e super powered international broadcasters found on higher frequencies Thus Co lumbia and Venezuela on 60 and other channels are ideal for the novice break Ing into Spanish language reception and also offer a number of rare catches for experienced DXers In addition there are at least a couple of stations with intriguing histories which make especially good loggings 60 Meters Two stations with which every novice should start are R Rum bos at Caracas Venezuela and R Suta tenza at Bogota Colombia R Rumbos Operates on 4970 kHz and is the key station for Venezuela s major network News from Cadena Rumbos often is heard on several Venezuelan 60M out lets R Sutatenza operates on two 60M frequencies 5075 and 5095 kHz both of which are just above the edge of the band and do not always carry the same programs This station operated by the Catholic church has a network but all outlying R Sutatenza s relays are on MW Both R Rumbos and R Sutatenza regularly issue QSL cards for correct reports by C M Stanbury Il Other inviting targets include R Con tinente another Caracas broadcaster which has a network at times on 5030 kHz Ecos del Atrato Quibo Colum bia on 5020 R Barquisimeto a R Rumbos affiliate on 4990 just below WWV s 5 MHZ time signal R Sante Fe Bogota on 4965 R Colosal sometimes announces as R Todelar TODELAR is another Colombian net work and so on right down to the l
127. e user can orient the columns so most sound is radiated forward or by aiming one side towards a side wall or a corner part of the sound can be reflected or diffused to provide a broad er or narrower sound field This system is designed for flat en ergy response a widely overlooked fac tor in speaker design The reason is simple once you re six feet away from a speaker up to 80 of the sound you hear is reflected off the walls ceil ing and floor of your listening room So even if the on axis response is ex cellent poor response ofl axis can make a speaker s treble sound dull Com bining excellent on and off axis re sponse produces flat energy and a bright completely realistic sound There are other design features which contribute to the AS 1344 s excellent ELEMENTARY ELECTRONICS March April 1977 sound too The woofers are located well above the floor so bass response is very solid and well defined There is no mid bass boom or resonance either so middle frequencies come through re markably clean and clear The tweeters deliver 10 to 20 dB more off axis out put than conventional tweeters for bright realistic highs and their 270 dispersion pattern maintains a well bal anced stereo image through a wide area What You Get Each column speaker is supplied as a semi kit The cabinet itself is factory assembled and finished All you do is put the drivers and cross over into the cabinet Overall dimen si
128. ears from sight along with the transceiver The antenna and power leads tuck up under the dash out of sight Of course that still leaves the CB antenna to consider because it s the first thing a would be thief looks for in a crowded parking 47 ee It s Sound Cookie L4 inch hardboard to make the stiffen ing flange If you make the circular cut with a saber saw cut slightly inside the line for the 37s amp inch diameter cutout first then cut outside the 5 inch diameter line You can obtain an al most perfect round opening by use of a drum sander chucked into a drill to remove excess material or by hand with sandpaper The outside cut is best smoothed by turning the flange against a disc sander or by hand filing to the line When you have completed these cuts place the speaker driver face down on a clean flat surface Place the mason ite piece smooth side down over the speaker to determine that it fits the MASKING TAPE TWIST TOP JAR NO I7 109 OZ FOOD CONTAINER WITH COVER ON SAW OR CUT USING EDGE OF MASKING TAPE AS GUIDE AUTOMOTIVE SPEAKER GRILLE SCREW ON COVER TOP SECTION OF FOOD 3 CONTAINER 2 GALLON GLASS ENCLOSURE COOKIE JAR GP FOR WIRING 46 SPEAKER LOCATION OF HOLES speaker frame all around When you are satistied with the fit turn them over and rotate the speaker to locate the mounting holes to the straigh
129. ece sock ets both provide 94 five point terminals plus two 40 point bus strips for a total of 550 solderless tie points Experi mentor 600 priced at 10 95 has a 6 10 inch center channel making it the only socket currently on the market with full 4 terminal fan out for microproces sors clock chips RAMs ROMs and other larger DIP packages Experimentor 300 priced at 9 95 has a 3 10 inch center channel that is perfect for smaller DIPs Continued on page 18 ELEMENTARY ELECTRONICS March April 1977 TEST SEMICONDUCTORS ANYWHERE Portable in circuit tester for all bipolar transistors Darlingtons Mai B amp K PRECISION MODEL 510 90 e Combines Dynapeak testing method with HI LO power drive e Tests semiconductors and identifies all leads base emitter collector in LO drive e Provides GOOD BAD indicator in circuits with shunt resistance as low as 102 shunt capacitance up to 25 uF in HI drive Test performed as quickly as one can turn the switch e Measures 69 x 33A x 1 e Weighs 1 2 pound less four AA batteries e Price includes test clips and carrying case Available from local B amp K PRECISION distributors i I amp PRECISION PRODUCTS OF DYNASCAN 6460 West Cortland Avenue Chicago Illinois 60635 312 889 9087 In Canada Atias Electronics Toronto CIRCLE 36 ON READER SERVICE COUPON Hey Look Me Over Continued from page 10 all channel conve
130. environment And pre tuned to an SWR of 1 9 to 1 E or less over the 40 channel sand 1 3to 1 or less at 2 the center To assure maximum range and peak ss performance everytime you key the mike That s what sets the White Knight antanna apart from all the otFers Ride full tilt into the 40 channel era with the new White Knight CB Antenna And take the Shakespeare performance route home i The White Knight Antenna Sty e 430 available in a variety of pre assembled mounting styles Complete with cables and connectors Under 25 7m Coming on strong for the Knights of fhe Road CB ANTENNA Shakespeare Company Amenna Group P O Box 245 Columbia S C 29202 The Soakeszpcare Company 1977 in Canada Len Finkter Ltd Onta ic CIRCLE 25 ON READER SERVICE CIUPEN 4 Showcase of New Products Dig It Multimeter Looking at numbers is easier and less apt to cause reading errors than reading a meter s pointer This becomes obvious s Checklist of Books for the Libraries of Technicians Hobbyists amp Students BALED MEW EDEN Uu U Master Transistor 1C Substitution Handbook 504 p 7 35 O Servicing Medical amp Bioelectronic Equipment 336 p 8 95 C Mode Railroad Electronics 294 p 224 il 5 95 OLinear IC Applications Handbook 280p 6 95 C Broadcast Engrg Maint Hdbk 532 p 235 I 19 95 C Complete Hdbk ol Locks Locksmithing 392 p 348 il 6 95 O Practica Soli
131. er up to the minute innovations n other words Sparkomatic has t e very best CB equipment And enov g3 CB equioment to meet the needs of evert CB er CIRCI F 17 AN RFAYED CEPDVICE CAIIPAN FROM TWIN MAMAS TO LUNCH BOXES WE HAVE HARDWARE FOR EVERY APPLE j hopar amati Com Milfor Pa 18337 717 296 dar and 1555 W Rosecrans Gardena Calif 90240 213 532 84 it visibility and safer operation can be ex pected No bending down to squint at a dial under the dash is required The KK 1080 sells for 9 95 with the at tachment to the KK 1080 console of any of the Kar Kriket remote stereo speakers Mcde s KK 3030 3040 3050 enthusi asts can bring the big home stereo sound with them on the road For more info on Kar Kriket products write to AFS 7999 Knue Road Suite 116 Indianapolis IN 46250 CB Music Album All Ears the latest release on Radio Shack s own Realistic label celebrates America s fascination with Citizens Band two way radio otherwise known as ears with ten new and original songs To pro duce the album Radio Shack commis sioned a select group of professional writers singers and musicians The re sult is an exclusive CB concert in special tribute to CB fans and easy listening music lovers All Ears includes con temporary music for every taste pop rock soul and country sung and told in the vernacular around which CB good CIRCLE 32 ON READER S
132. es 25 Cents Details Canapro Enterprises Box 215C Station H Montreal Que Canada CASH FOR BOXTOPS Labels details 15 Re fund Bulletin Box 503 Cape Girardeau MO R37n MONEYMAKING OFPORTUNITIES Con t 3 HOURLY stuffing envelopes Easy work Details free Feldco Box 228 Ryder Brooklyn 11234 FREE 1001 ODDS It s about 10 000 100 00 actually made at home by certain oddballs You ll never get over it Publico E Carlsbad CA 92008 BOOKLET How to have Money Mailed to you Daily 2 00 postpaid J amp J IO 15 Box 11766 Winston Salem N C 27106 RECEIVE 10 unique monesymaking plans 1 00 FLICKINGER Box 44 Antioch IL 60002 1 000 MONTHLY possible stuffing envelopes Free details DB 928 Asbury Evanston IL 60202 200 WEEKLY Mailing Circulars Samples 25 GRAHAMCO DPBX 99371 Tacoma WA 98499 MONEY Lots of it mailing letters Details free Postal 215 Hazel Mill Valley CA 94941 ADDRESS ENVELOPES FOR PROFIT 100 00 per thousand possible Send 25 plus stamped addressed envelope McDade 3031 Nottingham Markham IL 60426 500 00 WEEKLY IMMEDIATE Guaranteed home income stuffing envelopes FREE Supplies Send 25 Stamp Profits B725 DP3 Belen NM 87002 CASH in on mailorder at start New sensible method reveals how Free details Crescent D 1404 Roller Ocean New Jersey 07712 1 000 MONTHLY working home sparetime Write Gord
133. es auto matically on transmit 10 Hz to 30 MHz 99 95 EICO LR 3 LONG RANGER INLINE PREAMP Bring in those distant weak signals Boosts receiver sensitivity up to 20 db Automatic transmit receive switching 29 95 EICO CM 2 CHANNEL MONITOR AUTO SWITCH Automatically silences car radio when CB call is received transmitted 29 95 HOBBY AUTOMOTIVE I VE W BW 300 ALPHA BRAINWAVE MONITOR Lowest cost battery operated professional Biofeedback System IC Circuit design fea tures an active filter and 5 microvolt sensi tivity Complete with stethescopic earphone electrode headband and instructions Kit 34 95 Wired 59 95 885 TUNEMASTER ENGINE ANALYZER Automatic all in one test bench for all 6 or 12 volt ignitions conventional or transistorized Giant 6 meter with 6 color coded scales Com plete with tune up and trouble shooting manual Wired 59 95 FREE EICO CATALOG The more you know about electronics the more you ll appreciate EICO Every E CO prod uct is designed to provide you with the most pleasure and quality performance for your money The fact that more than 3 million EICO products are in use attests to their quality and performance BUILD IT YOURSELF and save up to 50 with our famous electronic kits For the latest EICO Catalog and name of near est EICO Distributor check reader service card or send 50 for fast first class mail service EICO 283 Maka Street Brooklyn N Y
134. evaporate various materials such as lead onto test surfaces These tem perature extremes make for unique testing conditions CALCULATOR HELPS WITH FLIGHT PLAN A programmable calculator that fits in the hand is the latest flight planning and navigation aid from Texas Instru ments for general and business aviation pilots TI has produced a library of 21 aviation programs for use with SR 52 card programmable calculators The pre recorded programs offer pilots an swers in seconds to flight planning and navigation questions including course position time speed temperature alti tude winds fuel consumption and weight and balance With these aviation programs the SR 52 can be a tremendous computa tional resource for the pilot who takes pride in his ability to navigate with pre cision The electronic calculator joins the mechanical flight computer and DEI I A 21 program library for SR 52 card programmable calculators has been introduced by Texas Instruments to help general and business pilots with flight planning and navigation plotter as a basic navigation aid To develop a flight plan for a trip with several legs for example a pilot inserts a pre recorded program on a small mag netic card into the calculator memory He then keys in the flight planning in ELEMENTARY ELECTRONICS March April 1977 Put Professional Knowledge and a COLLEGE DEGREE in your Electronics Career through Earn Y
135. ew TV offers In some video projection systems scanning lines are quite noticeable But more importantly all of the systems suffer from a lack of brightness albeit Ad vent comes fairly close to offering what might be called a bright pic ture via its triple tube lens Video Beam projection method The basic problem is that lens as semblies used in most video projec tions rigs are inefficient in collect ing the light available from the face of the picture tube and project 41 A SLT s d hotel lobhies ge lx addition to stores voull find video projection systems in public pl ces bars restaurants airports museums et Some of the publicly displayed sets inay nob however be readily available ta vou as a consumer To buy you might hav to work Ar oet an area files representative or contact the manufacturer f r SEI arrange ments The gnits carry intriguing space age designations such as Video Beam MagnacVision Megavision Stereovision Eye Beam lt Tele D Theatre Video Master Cine Vision and Th atervisioh huwever this cur rent crop of video projection systems is not the first time this idea has amerged It yas preceded by projec Adn TV system that avere develop edm the 1940 s he main difference between the current crop ahd tliat of the forties 18 that today s systems project color pictures dn addition to black and white avid they
136. f DXing pleasure writes Eric Steiner Park Forest IL Canada is a favorite MW listening target with CBW Winnepeg on 990 KHz and CBK Regina on 540 kHz Ronald L Gibson is serving with the U S Army at Ft Hood TX Ron says he is in radioteletype in the Army Do you have any press service RTTY frequencies We run at 60 wpm at 85 and 850 Hz shift We found a few like 14 693 KHz in Spanish We use this RTTY sta lions to test our equipment Not many private SWL set ups contain radio teletype gear so your Army hitch is giving you an excellent opportunity for some off beat DXing with RTTY A couple of newswire RTTY channels I d suggest which should be compatible with your 60 wpm 850 Hz shift equip ment are 15 607 kHz 18 145 kHz at 1400 GMT and 19 580 kHz Good fuck Bandsweep Times in GMT frequencies in kHz 1548 There s a new MW voice from the Caribbean on this frequency lately The station reported by BCB lis teners in the eastern part of the U S is VSI Radio on Grand Turk Island It rides just a bit lower than the nominal and announced frequency of 1550 It has been heard in English around 2300 4832 A DX Central hest bet for the SWL who has never really listened to and identified a Spanish speaking Latin American SW station is the Costa Rican powerhouse TIHB Radio Reloj pronounced roughly ray LOW Try any evening any time between 0000 and 06000 6 090 Radio Luxembourg In
137. former If you use a 28 volt trans former increase R1 s value to 270 ohms BRI is a 50 PIV bridge rectifier rated 100 mA or better Use the least expen sive type you can get If you have four discrete silicon diodes lying about sim ply connect them as the bridge circuit LED serves as both a pilot light and Charge indicator If the LED doesn t light the batteries aren t being charged The LED also serves as a fuse If the rectifier and RI short Completed charger chassis shows neat layout of parts Note knot in AC power cord just to the left inside of the rubber pass through grom met in the chassis Knot prevents power cord from pulling through grommet accidentally out the NiCads will attempt to dis charge through the diodes and the high discharge current could cause considerable damage But the LED will burn up almost instantly thereby open ing the circuit to the batteries The LED is the only critical com ponent in the sense you must be certain it is rated for a maximum of at least 50 mA We suggest a diffused LED be used as its light can be seen from the sides If possible use a Radio Shack 276 026 fer LED 1 To mount the LED simply push it through a hole in the front panel of whatever you use for the cabinet If you connect R1 between the LED and a terminal strip as shown in the photo graphs the LED will be held in posi tion without need for glue or a iamp mounting kit The cabinet can be plas tic or
138. g corporation a small company or even go into business for yourself Yes Electronics can be the door to a whole new world of career opportunities for you And CIE training can be your key Send for FREE school catalog Discover the opportunities open to peo ple with electronics training Learn how CIE career courses can help you build new skills and knowledge and prepare you for a meaningful rewarding career We have courses for the beginner for the hobbyist for the electronics technician and for the electronics engineer Whether you are just starting out in Electronics or are a college trained engineer in need of updating or anywhere in between CIE has a course designed to fit your back ground experience and future goals Send today for our FREE school cata log and complete career information For your convenience we will try to have a representative call to assist in course selection Mail reply card or coupon to CIE or write to CIE include name and date of this publication 1776 East 17th St Cleveland OH 44114 Do it TODAY A aX AC om c EN Xr III ne ae ey ye ee P LM Ci Cleveland Institute of Electronics Inc 1776 East 17th Street Cleveland Ono 4ana A ed Accredited Member National Home Stuay Council PProv Yes want your FREE school catalog and career information Under Package today l am especially interested in EL 80 G I Bill D Electronics Technology D Industr
139. get 78 tioned R Sutatenza has a mighty 250 KW outlet on 810 kHz and is the sec ond most powerful BCB transmitter in South America Another good prospect in the east is R Aeropuerto Barran quila on 1160 kHz Under normal conditions it often 1s heard after WJJD Chicago signs off at Salt Lake City sunset to protect KSL After that the major interference will come from a station in the Dominican Republic Radiolandia If you don t live too close to Dallas Fort Worth La Voz del Rio Cauca Cali with 50 KW on 820 kHz is a good bet This one belongs to yet another Colombian network CARA COL Out west R Colosal s BCB trans mitter often is heard around Midnight PST 0300 EST on its split fre quency of 1005 kHz Another good frequency to watch around 0300 EST is 1040 but only on Monday mornings when WHO Des Moines is off At those times R Tropical at Barranquila is usually on top but if you listen care fully R Super de Bogota also can be logged Secret Stations Over the past 15 years Venezuela and or the area around it has been home for two widely heard shortwave clandestine broadcast sta tions R Libertad La Voz Anti Com munista de America now defunct and R Euzkadi the Basque name for the northern part of Spain which is the official voice of the French based Basque government in exile and can be monitored daily by North American SWLs Although at opposite ends of the political spectrum R
140. good to know that I had introduced such an interesting and rewarding hobby to so many persons AWA Conference High Attendance at the AWA Conference reached a new high with over 400 collectors registered for the activities One of the highlights of the Saturday night banquet was the introduction of Mrs Alfred Grebe the widow of the brilliant designer of the ANTIQUE RADIO CORNER by James A Fred Grebe radios You are indeed fortunate if you have a Grebe receiver in your collection Of interest to all collectors was the announcement of the publication of The Saga of the Vacuum Tube by Gerald F J Tyne Mr Tyne has spent many years revising expanding and correcting a series of articles bearing the same name which was printed in Radio News magazine between 1943 and 1946 It is a detailed record ex tending to 1930 of scientific research pioneer inventions development by in dustrial teams and the applications and production of vacuum tubes It includes the story of science and industry com bining forces improve the early vacuum tubes to meet the needs of the military in World War I The book will contain nearly 500 photos and drawings of tubes 275 brand names of independently pro duced tubes are listed to aid collectors in finding and identifying tubes The book will cost about 25 00 As soon as defiinte price and ordering information is available I will have it in this column I am sure that it will be a
141. guage and includes simple pictorial hookup diagrams to help teach electronic theory as you work with each circuit The educational kit that s a step into the future for students beginners hobbyists of all ages Ask for 28 246 Some circuits require batteries not included SOLD ONLY WHERE YOU SEE THIS SIGN Radio Shaek A TANDY CORPORATION COMPANY OVER 5000 LOCATIONS e 50 STATES 9 COUNTRIES Retai prices may vary at individual stores and dealers Prices and products may vary in Canada ELEMENTARY ELECTRONICS March April 1977 Ask Hank HeKnows AC Tester Problems Hank I built vour AC outlet tester from the article Your AC Outlet Will Get You If You Don t Watch Out in the Septem ber Ocotber 1976 issue and had two technicians check it but the neon lamps don t light up right Sometimes they re dim sometimes give wrong or no indica tion What have I done wrong Help J G Chapel Hill NC ORANGE NE3 00K GND lt Licok R2 NEUTRAL HERI an R5 NE ee GREEN Z R6 NEI ASZ 300K Ld AW m lOOK Relax you haven t done anything wrong It seems some of those little neon lamps Got a question or a problem with a project ask Hank Please remember that Hank s column is limited to answering specific electronic project questions that you send to him Personal replies cannot be made Sorry he isn t offering a circuit design service Write to Hank Scott Worksho
142. has amp brigi er picture sources and FERRA screens with better reflective c pabiliti s brighter pictur amp source Fbettess re en Con bination makes it possihle to view then without totally darkening the some which they are used However for optimum brightness and quality most sets should be operated in totally dark ened rooms Even so projected pic tures simply do not have the punch that direct view TV pic tures hav that purich is related to the latte s brightness Well ix Theatervision setup is similar to Tel Pro Svstems Cinema JV Picture is 32 in x 40 in 40 TV Sets of The Future The picture Tele Pro Systems Cinema IV model CR costs 2000 and projects on a 30 by 46 inch screen which retracts into the console when not in use Lens directs light to mirror which inen directs nage to the screen not shown here plain the matter later Another big difference s the prices of today s systems are gen erally high Complete systems con sisting of TV source projector lens assembly and screen run from 995 on ap to 4 995 These ar for home use Models for professional indus trial use start at 5 000 and range to 44 000 However you can ex perience big screen projection TV for a lot less if you re a handy do it yourselfer Kits that utilize your ex isting portable or table model TV as the program source can be had for as little as 325 How
143. hat GB Whine O The next time your CB rig whines as you gun the motor blame it on yourself and not on Detroit Auto wir ing system are not designed to include communications systems Therefore you can expect interference from the al ternator the source of the whine Its up to you to eliminate the whine Nope not every model or car in a model group will produce a whine but when it does communications can be either a bust or reduced in reliability and usefulness To rid yourself of the alternator whine you could spring for a new al ternator rewire the harness or tune up the engine However there is an easier cheaper way install a mobile alterna tor generator feed thru filter It will help suppress unwelcome whine inter ference and completely or partially re duce other noises such as clicks and static caused by turn signals fan mo tors and other accessories A Sprague QXI 18 feed thru filter 80 rated at 40 amperes is shown in the photographed installation It is her metically sealed for protection against mechanical damage moisture grease and grime The ideal method of instal lation is to mount the feed thru filter right onto the alternator but in many cases this is impractical The photo graph shows the Sprague QXI 18 mounted next to the starter solenoid where the hot lead from the alternator meets the hot lead from the battery Before beginning the installation dis connect the lead from the batter
144. hat real time with no assistance whatsoever If you know someone who can use the Sony VR 35 system you can get more information by writing to Sony Business Products 9 West 57th Street New York NY 10019 M B DXing Colombia Continued from page 78 statements to the press the Basques set up intelligence networks in Latin Amer ica CIA financial support according to the gov t in exile continued through out most of the 1950s During that period R Euzkadi operated from a French site Today R Euzkadi has three daily half hour transmissions beginning at 1430 1530 and 1630 EST Thev use ELEMENTARY ELECTRONICS March April 1977 oy 301 Get acquainted with the new E CO products designed for the professional technician and elec tronics hobbyist Included in brochure are 7 IC project kits CO s Foneaids security products and many varied kits 302 International crystal has illustrated fo ders con taining product information on radio communica tions kits for experimenters PC boards crystals transistor RF mixers amp amplifiers etc 303 Regency has a new low cost high performance UHF FM repeater Also in the low price is their 10 channel monitoradio scanner that offers 5 band performance 304 Dynascan s new B amp K catalog features test equipment for industrial labs schools and TV servicing 305 Before you build from scratch check the Fair Radio Sale
145. hat the box has ventilation holes in the top and the bottom And after building the clock let it run for a while then unplug it and feel around to see how warm the box is inside Keep wires from resting on RI and R2 which tend to get warm and remember that good ventilation is important Finally all connections going to the fuse and to the primary side of TI and T2 must be wrapped with tape because there will be 120 volts on those points All the components can be mounted on a perf board about 2 in by 4 in First place all the components on the board by sticking the leads through the holes and bending the leads back to hold the components in place Trans formers Tl and T2 are small but are too heavy to put on the perf board so it is best to mount them on the bottom of the cabinet Likewise it is most convenient to mount the fuse on the cabinet so that the 120 V wire coming into the cabinet can go directly to the fuse and then to the transformers Of course switch S4 has to stick outside of the cabinet as do the pushbuttons With the components mounted on the board all you have to do is run con necting wires between the components 18 or 20 gauge wire works well When soldering wires to the clock module be very careful You must use a low heat iron 25 30 watts as recommended for all integrated circuit projects The pin connections on the module are actually holes that the wires are placed into and then soldered You can get to
146. he 30s were telephone jacks and plugs These continued virtu ally unchanged until the fall of 1976 Declining sale of these parts led the Mallory management to discontinue making jacks and plugs and certain types of switches After the present stock in the hands of radio distributors is exhausted there will be no more Mallory telephone jacks and plugs If you want to complete a collection of jacks or plugs you had better rush out and buy some while there is a stock available Thus another old familiar name first Yaxley then Mallory Yaxley and finally Mallory will disappear from the world of radio Stuck Headphone Caps I just dis covered a helpful tip that I want to share with you I recently purchased two pairs of old headphones The black composition caps were stuck so tight to the aluminum cups I could not unscrew them I even gripped the cups in a large vise but this did not help A friend sug gested that I put the phones in a home freezer overnight then remove them and immediately immerse the black caps only into nearly boiling water for a minute or two l did this and was quite pleased when the caps unscrwed with hardly any effort The reason this tip works is because the cold box caused the aluminum cup to shrink and the hot water caused the caps to expand This uneven coefficient of expansion caused them to come apart quite easily Next time I ll get back to the techni cal aspects of antique radio collecting We will h
147. he convenience outlet on the TRC 82 converter From then on the set can be turned on and off remotely from the comfort of an easy chair Jer rold s TRC 82 sells for 124 50 The extension control cord Model TRC 82 25CD is priced at 8 95 Car Stereo Hump Mount Acoustic Fiber Sound Systems has a new Kar Kricket hump mount console Model KK 1080 you will want installed in your wagon The KK 1080 combines a sculpted appearance with a design that CIRCLE 51 ON READER SERVICE COUPON permits mounting of any stereo radio 8 track or cassette system with storage space for four 8 track or seven cassette tapes The unit requires no fastening devices but simply rests on the drive shaft hump common to most cars vans and trucks Specially designed teeth in the base prevent movement while driving Yet by simply unplugging power antenna and remote speaker leads the entire unit may be lifted and placed in the trunk for maximum security And by placing the stereo units at a 45 degree angle to the driver better dial ASK ABOUT OUR SALE OF THE NTH MONTH D GUARANTEE SERVICE yh ONSEN You bet Buy a set this month and the antenna s on the house I BE FOREMOST with DIS 13 DOUBLE TALK antenna system Join the thousands of CB ers who communi cate longer louder while traveling over the miles with the Hustler Double Talk mobile antenna system Guaranteed superior per formance over a
148. he latest stereo music equipment ELECTRONIC DISTRIBUTORS INC 4900 N Elston Ave Chicago IL 60630 EE 15 DO IT YOURSELFERS let our buying experts get those hard to find radio tv auto or alarm parts for vou Complete details 25 Parts Procure ment Co Box 1304 EE Canoga Park CA 91304 REPAIR motors Generators Alternators Sup Plies Equipment plans Electroquip Box 7266 Kan sas City MO 64113 OSCILLOSCOPE KIT Assemble your own 5 scope Combined simple instructions and opreating man ual included Special price 69 95 Send check or M O Electronic Technical Institute Little Falls NJ 07424 Dept 2772 EMPLOYMENT INFORMATION OVERSEAS Jobs now hiring All occupations High pay Transportation Computerized reports 2 00 Transworld International Airport Box 90802 EEH Los Angeles CA 90009 FOR THE HOME FOR anyone who wants the satisfaction and economy of repairing furnishing and maintalning the furniture in his home Send 1 50 to FURNI TURE 229 Park Avenue South New York NY 10003 FORMULAS amp TRADE SECRETS HAVE YOU EVER WONDERED how some people seem to have all the luck and succeed in business Let us tell you It s not luck Details free with S A S E Motivation 461 Alter Ave Staten Island NY 10305 HI FI EQUIPMENT CANADIANS Free Hi Fi discount catalog Name brands immediate delivery from our huge stock Etco Dept AA Box 741 Montreal A
149. he transmission hump All nec essary hardware and detailed instructions are included Additional optional top sections are available to allow instant transfer of the transceiver from vehicle to vehicle or to a boat trailer office or home Easy Mount weighs 1 25 lbs has a low 1 in profile and occupies a mounting area of 4 in wide by 3l4 in deep It comes with a full year warranty For additional information write to Cornell Dubilier Electronics 150 Avenue L Newark NJ 07101 ELEMENTARY ELECTRONICS March April 1977 Swivel Whip CB Antenna new swivel adjustable CB antenna model M 275 has been introduced by Antenna Spe cialists The M 275 is a combined product of the famous M 175 CB antenna and a new swivel whip adaptor model M 279 12 The CIRCLE 45 ON READER SERVICE COUPON swivel whip adaptor provides for quick easy adjustment of the whip to compensate for sloping trunk mounts To adjust the anten na you simply loosen the set screw swivel to the vertical position and retighten The M 275 also incorporates a new low profile version of the original Quick Grip uni versal trunk mount that makes a permanent nstallation with no holes Manufacturer s suggested list price for the M 275 is 25 95 the M 279 12 is 4 25 For further infor mation contact The Antenna Specialists Co 12435 Euclid Avenue Cleveland OH 44106 Visor Speaker New from Superex the VS 19 visor speaker is designed speciall
150. hen they re applied to the input terminals ICI A and ICIB are connected in a configuration called a Bistable Latch SPEAKER or Flip flop This circuit can rest in either of two states Pin 3 at 12 volts and pin 4 at zero volts or pin 3 at zero volts and pin 4 at 12 volts The voltages fed to the input terminals pins 2 and 5 determine which state the circuit rests in The normal input condition for the bistable latch is ap proximately zero volts at both input terminals Pin 2 is held to about 0 5 volts by means of R2 Rl and the closed loop circuit of conductive foil between terminal L and ground Pin 5 is held to zero volts by means of resis tor R3 Under this condition the output voltage at pin 3 is 12 volts In order to flip the voltage at pin 3 to zero volts the voltage at input terminal pin 2 must approach 70 of the supply voltage or 8 4 volts This would be caused by the closed loop at terminals L to G being opened or a connection between terminals C and B When either of these conditions exists even for a few microseconds the output voltage at pin 3 is flipped to zero Re moving the voltage at pin 2 will have no further effect on the circuit It can be restored only by applying a voltage to pin 5 through the reset switch More on Circuit Operation Capacitor Cl between pin 2 of ICI A and ground controls the amount of time delay be tween the opening of the loop circuit and the activation of the alarm When
151. ial Electronics O FCC License Preparation O Electronics Engineering All CIE career Color TV Maintenance Other courses are ap O Mobile Communications proved for edu Be cational benefits under the G I Print Name Bill If you are a wanes res veteran or in ser i vice now check City box for G I Bill information State Zip Phone Age a Check box for G I Bill information O Veteran D On Active Duty From CIE Cleveland Institute of Electronics learn by doing Perform more than 200 exciting experiments with CIE s fascinating ELECTRONICS LABORATORY PROGRAM a i pi pn SEI ci ee I TE z E UPE s Put theo mno H L 4 ees LA n Pv aa et D ar bl e on 9 X X x Fog X exo Of OS X dM X i PLACE Classified To be included in the next issue please send order and remittance to R Wayner ELEMENTARY ELECTRONICS 229 Park Avenue South New York N Y 10003 ELECTRONIC EQUIPMENT amp SUPPLIES FREE CATALOG Electronic supplies kits for the hobbyist Low prices Anklam Electronics 4709 nth 61h St Wausau WI 54401 BUILD YOUR OWN TV CAMERA Great for home and business Free illustrated catalog Phone or write 402 987 3711 ATV Research 13 E Broadway Dakota City NB 68731 FREE 36 page catalog updated 5 times a Year Everything for the electronics hobbyist from TV an tenna wire to t
152. iate sound forward and have no way to resolve unusual acoustic problems such as ex tra long rooms or walls unusually hard reverberant or unusually soft dead listening areas Here s how many unusual sound re producing problems can be handled Just use a pair of Heath s AS 1344 Two Way Column Speaker systems Unlike most hi fi speaker systems which have all the drivers facing in one direction the Heathkit column has matching speaker systems on two sides for a total of four driver units per column Each side system consists of a 6V2 inch wooler and a l in dome tweeter Both systems are driven in parallel with a crossover and a mod erate 3 dB high frequency roll off switch which may be used to compen sate for hard rooms The impedance rating of each column speaker is 4 ohms Two fuses protect the woofers and tweeters against execessive power input Parts for the crossover network and the tweeter level switch are mounted on plate which goes on the bottom o the cabinet Step by step instructions make this kit easy to put together even if you ve never as sembled a kit be ore e e assembles the HEATH AS 1344 2 WAY COLUMN SPEAKER One evening project yields high fidelity speaker system at real savings Heath provides several illustrations in the instruction manual showing speaker placement for various acoustic conditions Because each speaker radi ates sound energy equally from two sides th
153. iecting shield amp 2 ed Pe s in amplifier magnifies C signals 100X over omni direction mikes Catch sounds never bef heard highest signal to noise ratio poss Fy ib 299 00 Ppd For greater relaxation amp concen tration monitor your Alpha Theta bratnwaves w aud or vis Sig on Biosone Il Feats of 200 up units incl 3 feedback modes 4 ib About the size of a small match box Amazing volume amp clarity depends on locale Insert j earplug incl amp directional AM mini ma rvel plays Runs ab 100 hrs on 2 hear aid batts incl LESS THAN 1 QZ No 1976EK 14 95 Ppd Save your 4095 wasted heat to warm a basement garage rec rm at no extra cost Direct it your way instead of up the chimney Fan forced clean hot air via easy ducting THERE IS NO OTHER TELESCOPE LIKE IT THE NEW EDMUND 41 f 4 NEWTONIAN WIDE FIELD REFLECTOR TELESCOPE Clear bright spectacular wide angle views of Stars moon comets easy to use portable IN SECONDS YOU RE SCANNING THE ASTOUNDING UNIVERSE able to see and study the breath taking Cosmos as perhaps you never have before awesome vastness unbelievable orderliness stark Silent beauty Ail the fascinating heavenly mysteries are yours to enter and explore This new refiector telescope makes it easy for everyone to Spana thousand light years to space age enjoyment of the heavens and outdoors No complicated set up Just insert the eyepiece focus and
154. ignals DXer Person who listens for DX GMT Greenwich Mean Time the uni versal time standard also known in the military as Z or Zulu time It is equivalent to EST 5 hours CST 6 MST 7 and PST 8 Hz Hertz a unit of measure meaning one cycle per second kHz kiloHertz a frequency measuring unit 1 000 cycles per second MW Medium wave also called by lis teners BCB for broadcast band the range of frequencies below short wave between roughly 540 and 1600 kHz Sw Shortwave SWL Shortwave listener ELEMENTARY ELECTRONICS March April 1977 tween the antennas This is rare and the store s communications are as reliable as the telephone FM vs AM on Two Way Hank what is the advantage of FM 2 way communications over AM like we have on CB J W Scottsdale AZ FM can be said to have superior signal noise ratio lower usable signal level re ceived signal does not deteriorate gradual ly with distance between receiver and transmitter carrier power does not depend on audio power and interference with weaker signals on the s me frequency does not exist FM is the way to go if you need 100 percent reliability without in terference Gets the Lead Out What would happen if a lead acid bat tery was shorted out by a heavy bus bar that could not melt My buddy says noth ing but I don t think so What do you think R K New Hyde Park NY The lead acid cell like any other bat ter
155. ilt a super vacuum chamber to study possible materials for future computer components Dr Thompson is holding a replica of an evaporator being used to deposit extremely thin film layers inside the supervacuum chamber fot the Experimenter INTERNATIONAL CRYSTALS and KITS 02 Calibration Tolerance EXPERIMENTER CRYSTALS HC 6 U Holder 425 ea Cat No 031300 can be measured however the one cubic foot 03 cubic meters chamber appears to approach the emptiness of interstellar space This supervacuum is achieved by cooling the chamber to only a few degrees above absolute zero This method is not unique in that it has been used for many years in small chambers said Dr William A Thomp son one of the chamber s developers Our main contribution is that we have tried to make a gencral purpose vacuum OF 1 OSCILLATOR 325 The OF 1 oscillator is a resistor capacitor circuit providing oscillation over a range of frequen cies by inserting the desired crystal 2 to 22 MHz OF 1 LO Cat No 035108 18 to 60 MHz OF 1 HI Cat No 035109 Specify when ordering Specifications 3 to 20 MHz For use in OF 1L OSC Specify when ordering 20 to 60 MHz For use in OF 1H OSC Specify when ordering 031310 Enclose payment with order no C O D Shipping MXX 1 Transistor RF Mixer 3 to 20 MHz Cat No 035105 20 to 170 MHz Cat No 035106 SAX 1 Transistor RF Amp 3 to 20 MHz Cat No 035102 20 to 170
156. in your car and if it s a late sedan American model it most likely has rear shelf speaker cut outs with wiring already going to the dash It s a simple matter to install a pair of rear speakers and the sound with the trunk as an enclosure is usually a heck of a lot better than an itty bitty plastic or cardboard box Just use these car radio speakers for the cassette player and you save not only the cost of the speakers but usu ally the installation time and effort The diagrams show how to make the speakers do double duty The dia gram shows the typical car radio speak er hookup Note that even though each speaker has two connecting wires there is a common ground system The radio actually has only two wires for the left and right speaker outputs with the ground the car s body serving as the common speaker connection So al you need is a double pole double throw switch for the speakers to be used for both the radio and tape player The speaker switch can be mounted on the bottom lip of the dash next to the tape player mounting bracket To make life easier solder leads on the switch before it is installed on the dash then splice the switch leads into the radio s speaker wires later You can either pocket the savings on the speakers or put it into a better PUT YOUR CASSETTES ON WHEELS Use car speakers for fast inexpensive installation by Herb Friedman HIGH FIDELITY SPEAKERS SOLID STATE STEREO AM FM MU
157. ind that even free CB checkouts include a receiver test with B amp K s Model 2040 CB Signal Generator Smart REACT teams and CB clubs might well get their own Model 2040s to insure their mem bers have transceivers working at opti mum The B amp K Model 2040 is so well thought out that even an inexperienced non technical CBer can test a trans ceiver for receiver sensitivity adjacent channel rejection single sideband and opposite sideband suppression delta clarifier fine tuning AGC action and even ANL automatic noise limiting and noise blanker effectiveness Though all these are highly technical tests that generally require a skilled service tech nician the Model 2040 lets any high school student get trained in less than an hour to run a complete accurate receiver checkout What makes it so easy is that all the 2040 s operating fea tures are conveniently grouped in three sections on the front panel as shown in the photographs In the center is the channel selector that covers all 40 channels showing both the channel number and the exact frequency The selector covers more than 40 channels because it provides output on the unassigned frequencies between some of the CB channels as well as a few frequencies below and above the CB band The extra frequency coverage is provided to permit any type of test on any channel For example the frequency between channels 11 and 12 are not assigned to CB We can call this freque
158. ing 159 The modern world is a global village when you own the versatile DX 160 Five bands covering 130 kHz to 30 MHz let you monitor all types of transmissions from all over the world Pick up all che CB channels both AM and SSB Hear local programs and news from places like Paris London Cairo Rome Moscow Tune in longwave aviation marine weathercasts and special civi defense frequencies Receive WWV time signals and radio propagation forecasts And you ll be surprised at the DX power you get on the standard AM band Eleven controls and switches let you really pull out distant sta tiors Main tuning control plus bandspread tuning calibrated for the Amateur bands A product detec tor and BFO assure superior SSB and code recep tion Controls for audio and RF gain BFO pitch and antenna trim Switches for automatic noise limiting AM to CW SSB fast or slow AVC and standby for use with a transmitter FET s in all critical stages for maximum sensitivity and selectivity and crystal filler IF stages for reduced noise llluminated S meter Headphone jack And the matching speaker is included U L listed The DX 160 what a way to travel Radie Shaek A You get your own Experimental Electronics Laboratory work with components comparable to those used by industry i g With CIE s Experimental Electronics Labora tory you ll perform actual experiments and become adept at handling components This valuable
159. k alike The drawing labeled A is known as a closed pattern If you will start at any point in the figure and follow the line you will return to the starting point The figure is continuous it has no beginning or end The drawing labeled B however is not continuous it has a beginning and an end Its pattern is open The three points of tangency at the top and one point of tangency at the side are easy to count in A But the three tangent points do not appear in B The problem can be resolved by counting tangency points ELEMENTARY ELECTRONICS March April 1977 Three to One Lissajous Ratio A B in halves instead of units in an open pattern Each line that terminates at the top or side is a one half point of tangency Each loop is considered to be two ends or two one half points Counting at the top there is one loop two halves plus one end one half for a total of three halves At the side there is a single end for one half The vertical horizontal ratio is three halves divided by one half or 3 1 A continually shifting Lissajous pattern results when the phase relationship between the two input signals is constantly changing The more complex the pattern Lissajous Figures Sample Phase Measurements E resulting from a frequency ratio having large numbers such as 17 13 the harder it is to interpret It is better then to simplify the ratio if possible by changing the known frequency Other samples of frequency me
160. l Injector Circuits These are not unprofessional breadboard experiments but genuine radio circuits constructed by means of professional wiring and soldering on metal Chassis plus the new method of radio construction known Printe ircuitry These circuits operate on your regular AC or DC house current THE EDU KIT IS COMPLETE You will receive all parts and instructions necessary to build twenty different radio and electronics circuits each guaranteed to operate Our Kits contain tubes tube sockets vari able electrolytic mica Ceramic and paper dielectric condensers resistors tie strips hardware tubing punched metal chassis Instruction Manuals hook up wire solder selenium rectifiers coils volume controls and switches etc in addition you receive Printed Circuit materiais including Printed Circuit chassis special tube sockets hardware and instructions You also receive a usefui set of tools a professional electric soldering iron and a seif powered Dynamic Radio and Electronica Tester The Edu Kit also includes Code Instructions and the Progressive Code Oscillator in addition to F C C Radio Amateur License training You will also receive lessons for servicing with the Progressive Signal Tracer and the Progressive Signal Injector a High Fidelity Guide and a Quiz Book You receive Membership in Radio TV Club Free Consulta tion Service Certificate of Merit and Discount Privileges You receive al
161. l parts tools instructions etc Everything is yours to keen PRINTED CIRCUITRY At no increase in price the Edu Kit ages and back amp rounds have successfully used the Edu Kit in more than 79 coun tries of the worid The Edu Kit has been carefuliy designed step by step so that you cannot make a mistake The Edu Kit allows you to teach yourself at your own rate No instructor is necessary o a E uv now includes Printed Circuitry You build a Printed Circuit Signal Injector a unique servicing instrument that can detect many Radio and TV troubles This revolutionary new technique of radio construction is now becoming popular in commercial radio and TV sets A Printed Circuit is a special insulated chassis on which has been deposited a con ducting material which takes the place of wiring The various parts are merely plugged in and soldered to terminals Printed Circuitry is the basis of modern Automation Electronics A knowledge of this subject is a necessity today for anyone in terested in Electronics Z m E EH 9 ADDRESS TIE BUILD 20 RADI CITY amp STATE ps a PROGRESSIVE EDU KITS INC 1189 Broadway Dept 583DJ CIRCLE 13 ON READER SERVICE COUPON Reg U S Pat Off Training Electronics Technicians Since 1946 FREE EXTRAS SOLDERING IRON ELECTRONICS TESTER e PLIERS CUTTERS
162. lack cable 48 It s air sealed inside an acoustic fiber board enclosure AFS s patented Work ing Wall enclosure that has cross laminated tubular fiberboard construc tion The power handling capability of the speaker system is rated at 5 watts RMS 9 watts program and 13 watts peak It has a frequency response of 150 to 10 000 Hz and an 8 ohm impedance The entire unit is finished with a newly developed plastic trademarked Copolymer that is resistant to impact and extreme weather conditions It comes in one color black Duralex The unit is 634 in high 8 in wide and 12 in deep It weighs only 3 pounds not counting the CB trans Be sure to connect antenna cable to CB rg when installing the Kriket on hump ceiver you will mount onto it It comes complete with connector cord with a mini plug The KC 3085 has a sug gested retail price of 29 95 Easy Installation Connecting my CB transceiver to the Kriket Kamel was no effort at all especially since let an eager male who was hanging around do the job for me It s not that Fm one of those helpless type females but I figure it does no harm to let the hoys demonstrate how clever they can be too at least once in a while There s a slot on top of the Kriket that fits just about any CB mounting bracket and it takes only moments to attach the two bolts The single short connector cord coming from the Kriket s The completed install
163. ledge not required sales handied by professionals Postcard brings facts about this unusual Opportunity Write today Barta xq Box 245 Walnut Creek CA 94597 MICRO MINI MIKE WIRELESS MICROPHONE World s smaliest Solid state self contain ay ed Picks up and transmits most sounds F without wires up to 300 ft through FM Ra M dio Use as mike ampf alarm amp alert sys B hat line baby sitter etc Money back guar B A M C cds COD ok 18 95 pius 1 00 BB j post amp hdig Calif res add tax Mail orders n SIZE only Qty Disc Avail AMC SALES INC a 2w x34 xvz Dept M24 Box 928 Downey Calif 90241 mm um um MES NE NEED NES NE QUUD NA ND ee ee ee GEN Em ee 90 mobile you must add a key operated power switch which is accessible from the outside of the car or place the power switch in the trunk Otherwise the circuit would be tripped as you open the door to leave the vehicle Shown above is exact size Newscan 26 work capacity of dictation equipment He can record stop rewind replay and erase When finished his words have been captured on a standard cas sette that can either be used directly or turned over to a typist for hard copy At the heart of the VR 35 system 1s a modified Sony BM 35 dictating ma chine A small control box sits next to this machine or can even be mounted On a moveable boom for use when a person is in bed The equipment is plugged into a s
164. low PL1 Phono plug see J1 above PL2 Plug to match transceiver power input receptacle 1 Switch SPST Radio Shack 275 602 or equiv Misc Cabinet terminal strips wire solder etc 49 Kathi s Kamel lot But that s no problem either if it s of the removable type or one that folds out of sight into the car trunk Another alternative is to use a com bination antenna that serves your CB as well as regular car radio this way you can leave the antenna in place and the thief never sees that second antenna that advertises the presence of CB equipment With all evidence removed there s no reason for even the most per sistent crook to go hunting in your locked trunk Improved Sound I d root for this kind of hump mount even if there were no other advantages Actually you also get greatly improved audio with your CB rig because the mount is also an extension speaker If you have not yet tested your CB with an extension speaker that is larger than that mini scule thing jammed into your trans ceiver you have a pleasant surprise coming The 3 inch waterproof speaker in the Kriket Kamel provides greatly improved clarity and intelligi bility across the entire voice range The speaker features a 3 ounce cera magnet mic and X inch voice coil The power cable is assembled with crimp on connectors with the length selected to provide easy connection to the cigarette lighter with minimum s
165. lso get good sound if you use the slightly less expensive Radio Shack driver number 40 1284 which costs under 10 If you really must save money and get the best sound for the money use number 40 1909 which is under 6 00 Finally you can shave some money off this not much by using number 40 1240 which goes for M M M M M Put Your Cassettes On Wheels Continued from page 67 10 sheet metal screws are satisfactory if air conditioning ducts prevent you from reaching behind the dash to install nuts on machine screws The wire from the terminals on this part of the mount are spliced directly into the speaker wires from the switch you installed and into the power wire going to the car radio Or you can connect the power wire to the accessory terminal on the fuse block If you haven t used a fuse between the player and the terminals on the slide mount you must install a fuse between the power source and the wires coming from the dash mount ter minals You can usually remove the 5 79 apiece You ll get as much sound probably more with this unit but the bass won t be as good These speakers can be used in pairs for stereo music listening or as remote speakers in the bedroom kitchen etc when larger more elaborate speakers are used in the living room or music room for serious listening You can also use one such speaker to make a table radio or TV set sound better And of course you can use four of the
166. ly However all of the functions will be fundamentally the same Be fore using an oscilloscope it is wise to carefully study ELEMENTARY ELECTRONICS March April 1977 the manual that comes with it Develop the habit of taking all readings with the greatest accuracy possible An oscilloscope can be used for several different types of measurements You know it is most often used to study the shape of a waveform when checking the performance of equipment The pattern on the scope is compared with the signal that should appear at each test point and a judgment is then made as to whether the operation of the equipment is good or bad Turning the Scope On First make sure the scope is plugged into an electri cal outlet Many people have turned all knobs on the front panel out of adjustment before they noticed that the power cord was not plugged in On most scopes the power switch is part of the Intensity control Turn the knob until a click is heard Let the scope warm up for a few minutes so that voltages in all of the circuits become stabilized DIFFERENT FREQUENCY OUT OF PHASE Getting a Pattern on the Screen When putting a pattern on the screen adjust the Intensity and Focus controls for a bright sharp line If other control settings are such that a dot instead of a line appears turn down the Intensity at once to pre vent burning a hole in the screen coating Brightness and sharpness will vary at various frequenc
167. m the beginning All these features in addition to the usual insert cassette to start and volume tone and balance controls Another excellent value is Radio Shack s model 12 1815 which has an extremely sensitive FM stereo radio sec tion It s priced the same as the tape only model but omits the reversing ac tion of the tape only job The FM section of this unit is extremely sensi tive and is the best FM car radio tuner we ve checked Safety First Now all you have to do is make cerfain it isn t ripped off before you get a chance to enjoy it Firstly a standard auto theft alarm is not protec tion for a tape player According to pclice estimates the average tape player or CB can be removed in less than 20 seconds The rip off artist can have your player out and be gone before the neighbors realize that sound is your cars burglar alarm And if you use a locking bracket and don t have an alarm ycu give the hoods enough time to chop the player free usually causing severe damage to your car s dash in the process But no one can steal what isn t there Simply install the cassette deck with a slide mount and you can easily slip the player under the seat or stow it in the trunk Its simple Slide mounts are available in several different models some with locks some without Forget the locks they only cause grief if some hood chops the lock out Even if the slide mount you get has a lock don t use it just hide the pl
168. matching the characteristics of the wave forms to those shown on an oscilloscope By using a graticule whose lines have been given voltage values in accordance with the amplitude of a known voltage the voltage at each of the test points could be checked Lissajous Figures The phase relationship between two waveforms and the frequency of a signal can be measured on an oscilloscope Patterns placed on the screen to ac complish this are called Lissajous figures A Lissajous 85 Number of Cycles on the Screen Because distortion often exists at the beginning and end of a sweep it is best to put two or three cycles of the waveform on the screen instead of only one The center cycle of three cycles provides an undis torted waveform in its correct phase The center of a two cycle presentation will appear inverted even though it may be undistorted The relationship between the frequencies of the waveform on the vertical plates and the sawtooth on the horizontal plates determines the number of cycles on the screen The sweep frequency should always be kept equal to or lower than the waveform frequency it should never be higher If the sweep frequency were higher only a part of the waveform would be presented on the scope Proper Display of Waveforms THREE CYCLES e CYCLES CENTER CYCLE CENTER CYCLE As the preceding drawing shows three cycles of the waveform will be on the screen when the sweep fre quency is set to
169. me to see an an tique radio receiver with an old pair of headphones or a horn speaker being powered by a power supply in a gray hammertone box Some collectors have built power supplies into a wooden cabinet which is a copy of an old radio cabinet Why not go one step further and use an actual B battery wrapper to enclose power supply With this idea in mind I built two power supplies one a combined A amp B supply A batteries power tube fila ments and B batteries power the plate circuits and two just a 22 and 45 volt DC supply In order to keep the supplies as small as possible I used the wrappers from a Burgess 5308 45 volts tapped at 22 volts 5 inches high by 4 inches wide by 2 2 inches deep I had found three dead batteries in an industrial plant where they had been used in a high resistance bridge You may have to modify your supply if you can t find batteries of this size or larger The combined power supply delivers 3 3 volts regulated for the filament of a 199 tube and 45 volts Zener diode regulated for the B voltage This supply powers a one tube regenerative receiver an Ace model V manufactured by Powel Crosley The other supply de livers 224 volts and 45 volts It is used with a Clapp Eastham regenerative re ceiver which has one 201A tube A 6 volt storage battery supplies the fila ment power Because you may not be able to find exactly the same batteries that I did I will tell you how to
170. member from e e the Computer Readout compli And those articles will still be alive let s satisfy our microP lovers In the Masthead put Norm Myers play up to reader desires And ele will be the magazine to discover B M Red Bank NJ You really put it on the data bar 10 4 CB Straight Up I claim that a CB vertical base antenna can be close to a TV antenna without causing interference with the TV reception After all the TV antenna is horizontally polarized and the CB is vertically polar ized What do you say Hank R D Waco TX Well first the TV mast usually made of metal will cause some signal loss on CB Also it will wreck your omnidirectional antenna pattern The TV lead in wire will pick up some signal since it is vertical If Well mercy sakes back door looks like we have a convoy HOBBY W RA p COMPLETE WITH BIT AND SLEEVE ONLY 2 495 OK MACHINE amp TOOL CORPORATION Bronx N Y 10475 212 994 6600 Telex 125091 3455 Conner St the TV set is not aligned properly or the front end is easily overloaded the CB signal can cause problems But it s the CB harmonics that ll cause the most problems Distance between the CB and TV antenna wil decrease possible interference Ra ta ta ta tatski What is this machine gun signal 1 hear on the amateur frequencies 1 monitor the ham bands and would like to know K M Skokie IL It appears to be a Soviet over the ho
171. multiplex adap ter tor his Heathkit AJ 30 tuner A Victor King needs a schematic diagram for a Magnavox Clock Radio C003 Run 1 He s at 832 E Garfield Glendale CA 91205 A Merle Hobbs of Rt 1 Box 160B Pitts burg KS 66762 needs schematic diagram and service data for a Knight CB Model Safari l A Wayne Wesi 106 E El Camino Phoe nix AZ 85020 needs schematic diagrams for the following RT 70 GRC transceiver APN 9 Loran navigation set and ARC 3 receiver A Hallicrafter S 38 receiver in need of repair Send schematic diagram and other data to John E Hinant 2712 Stacie Rd Richmond VA 23224 A4 Carroll M Brown of 1233 Crestview Dr Hurst TX 76053 wants the schematic diagram for a Hammarlund HQ 110 receiver A Eric Haggland of 7220 Mt Vernon Riverside CA 92504 needs diagrams and into on the SC 759A receiver and RA 94 power supply Also he can use a VT 145 A Help a Watterson shortwave receiver model 67 restored by supplying a sche matic diagram to Cedric Silverthorn 4110 Leeshire Houston TX 77025 All our readers who write for help al ways extend their thanks in advance And your good buddy Hank thanks you 73s Receiver Feature What is an RF gain control on a CB transceiver Is it a real advantage S N Wrightwood CA You can put an RF gain control to good use in CB operation Most sets don t have them They operate as if the missing con trol was set to maximum RF gain That s good
172. n Civil Mechanical Electrical and Chemical Engineering Technologies These degree programs are not mere stepping stones to higher education nor are they primarily intended for trans fer toward more advanced degrees They are practical career oriented programs designed to help you reach your objectives without further academic training FREE DEMONSTRATION LESSON No one can promise success but if vou want more more money more security more day to day satisfaction and more future our free Career Booklet and free Demonstra tion Lesson can help you get started in the right direction Just check the box next to the field that interests vou most anc mail the postpaid card today There s no obligation Remember it s your lite You might as well make the most of it IGS International Correspondence Schools Scranton Pa 18515 1976 Intext Inc J M E GS ad eme t OR am ah o EA F aaith 1 a gt X E 3 haer a
173. n get by for less He can buy a video projection system kit Four companies make them Here are their products Miami Projection Television Kit consisting of 12 8 12 inch focal length lens in five inch barrel that fits into 64 inch square lens mount and 30 by 40 inch curved screen in 40 by 40 inch black matte frame Price 325 Units mav be bought separately the lens at 225 the screen at 100 Also available is a matching screen stand at 50 Ac commodates sets up to 15 inch size Altervision Kit comprised of pro jection lens assembly and 35 by 40 inch Ektalite screen for use with sets of 12 to 19 inch tube size Price 395 To be available soon is a de luxe lens assemblv screen combina tion to sell for about 600 Television Projection Systems Lens system priced at 399 95 for use with portable TV sets to 15 inch size Includes instructions for build ing cabinet to house TV and lens Also available at 499 95 with pre cut cabinet components for at home assembly Optional 40 by 40 inch Ektalite movie screen available at 114 95 Melody Music Co Kit consisting of projection lens system and 32 by 40 inch screen combined in a sin gle cabinet For use with portable TV sets to 15 inch size Price 795 A consideration in buving kits is that the qualitv of the TV set vou use with them determines the ulti mate qualitv of what vou see on the giant screen State of the art TVs with bright picture tubes will
174. n of the Avanti Model AV 800 Low Pass Filter 24 95 on the transceiver should clear up the prob lem If the problem is at the TV receiver due to so called front end overloading 72 e e puts together in one neat package some of the newest CB rigs antennas and accessories for you to use in CB contacts this year installation of Avanti s Model AV 811 Filter 14 95 on the TV lead in should solve it The filter lets the TV signals come through the line unhindered while choking off the incoming CB signal The third type problem is caused by transmission of the CB signal through AC power lines This calls for the FILTER RADIO yA Y S BAND T FOR CITIZEN 58 onus Wet vane yEGLIGIELE P ut 05 CIRCLE 44 ON READER SERVICE COUPON Avanti Model AV 820 AC Line Filter 19 95 When used at the TV set this filter pre vents CB signals from entering the TV through the AC line Get the facts direct from Avanti Research amp Development Inc 340 Stewart Avenue Addison IL 60101 Magnetic CB Here s a new idea for mounting a CB rig and avoiding theft The Fasy Mount uses three powerful permanent magnets to make posi tive contact assuring maximum signal trans CIRCLE 57 ON READER SERVICE COUPON fer Ordinary slide brackets use flexible metal strips which can bend and wear In stallation is extremely simple and gives a neat flush mount appearance You have a choice of installing Easy Mount under the dash or on t
175. n voltage from the voltage measured at X From a tube manual determine the load current your supply must deliver This is determined by the tubes in your receiver Remember with a Zener diode Whether you build the A battery only or the A and B battery they ll look like this if you can locate an old case 44 TI 125 VAC PARTS LIST FOR THE ALL ELECTRIC B BATTERY BR1 Bridge rectifier 50 PIV Radio Shack 276 1146 or equiv BR2 Bridge rectifier 200 PIV Radio Shack 276 1172 or equiv C1 250 uF 75 VDC electrolytic capacitor obtainable from local radio TV parts dis tributor C2 500 uF 50 VDC electrolytic Capacitor from parts distributor C3 20 000 uF 20 VDC electrolytic capacitor Allied Radio number 852 0871 Note All capacitors in this circuit are approxi mate values Any higher voltages and or higher capacitances are acceptable but may take up somewhat more space Rt 2 2000 ohm 3 watt resistors Allied Radio number 880 5334 or equiv Different value may be required according to tubes you power Consult text on this page either the load draws the current or the Zener does The Zener must always have a current flow through it so we allow 10 of the load current for the Zener To determine the resistance of R use Ohm s law and divide the ditler ence between the load voltage and the voltage at X by 110 of the load cur rent If you use two filter capacitors as I
176. n your license if you re willing to put forth an effort be cause the vast majority of CIE students have In fact based on continuing sur veys close to 4 out of 5 CIE graduates passed their FCC exams That s why we can offer this Warranty when you successfully complete any CIE career course which includes FCC Li cense preparation you will be able to pass the Government FCC Examination for the License for which the course pre pared you or you will be entitled to a full refund of an amount equal to the cash price of tuition for CIE s Course No 3 First Class FCC License in effect at the time you enrolled This warranty is good from the date you enroll until the last date allowed for completion of your course That s it We warrant that you will get the License you trained for You ll have attractive job opportunities There have already been many exciting developments and breakthroughs in Elec tronics and some people might assume there will be no new frontiers no new worlds to conquer Not so Electronics is still growing In nearly every one of the new and exciting fields of the Seventies you find electronics skills and knowledge in demand Com puters and data processing Air traffic control Medical technology Pollution control Broadcasting and communica tions Once you have the solid technical background you need you can go after the career field you want work for a bi
177. nce s listening patterns It would be senseless to schedule an English language North American shortwave service at 10 a m Eastern Standard Time Relatively few listeners will be around to tune in Most U S and Canadian listeners do their tuning during our evening hours Thus you will find many internaitonal broad casters beaming programs our way in English during our prime evening time say 0100 to 0600 GMT By the same token the English language programs from the larger African and Middle Eastern stations which Stateside listeners are able to hear during our afternoon hours are probably intended primarily for an audience in Great Britain Our afternoon is evening there and the time when the largest British audience is available For propagational reasons reception during our prime evening hours is gener ally better for stations to the east of us Europe and Africa because a path of darkness exists between transmitting and receiving points Asian stations are at somewhat of a disadvantage They are further away from us but in addition their most favorable reception paths to North America occur in the early morning not the ideal listen ing time for listeners here Strange things result For years Radio Thailand has scheduled a so called North American Service in English from 0415 to 0530 GMT This is a terrific time in terms of having a listening audience avail able in North America But it is a wretched time propag
178. ncy channel 11A If you were testing a receiver section set for channel 11 for adjacent channel rejec tion on the high side 10 kHz you d find the frequecy 10 kHz above channel 11 is not channel 12 but channel 11A With the Model 2040 you can get pre cise output on channel 11A The same thing applies with the hole in the band between channels 22 and 23 The hole was previously two channels wide Now with the 40 channel band the hole becomes channels 24 and 25 You 81 Kathi s CB Carousel Now I m certain that every one of you readers know at least one CBer us ing a powermike that puts out a really solid easy listening signal with no distortion or splatter so before you start writing about these exceptions that prove the rule let me explain how you get not just good but great results with a powermike Punch With Quality First not every powermike has a built in amplifier they are simply superb microphones speci fically tailored for mobile communica tions Regardless of how impressive the case looks most mikes supplied with low to moderate quality transceivers are simply miserable their sound is muddy and distorted Just replace the typical CB mike with a quality job such as used for police fire and govern ment transmitters and in one stroke you clean up your signal and pack in solid modulation at the intelligence carrying midband frequencies Where do you find such a mike You find 1t masquer ading as the
179. nd signal which is quite illegal Another World So what we have is a wide assortment of available equipment combined with hundreds of thousands of operators who have such gear and the will to use it and the FCC who seems little more than totally befuddled by the whole situation High Fr quency The so called high frequencies are the stomping grounds for many more illegal stations that use the lower frequencies below Channel 1 Up until the advent of the expanded CB channels the high frequency band started on 27 265 now Channel 26 MHz and went on upwards to about 27 755 MHz almost the low frequency edge of the 10 Meter ham band Opera tions between 27 265 and 27 315 MHz were uSed primarily by AM operators while 27 325 MHz and above were oc cupied by Sidebanders Some CW code operation has also been noted The CB channels now end at Chan nel 40 27 405 MHz so those who have elected to operate on unauthorized channels have had to move their opera Continued on page 91 dr a upon proof of qualification for the following Communications Award For Sidebanders Service Bureau P O 8ox 381 Smithtown NY 11787 h m Rm o m ik ie ee 4d amp Y lu k i a li a 5 a ELEMENTARY ELECTRONICS March April 1977 fuel supply Music Machine You can write your own song in the form of codes stored in successive memory locations You specify the pitch and length of each note
180. ne of the very few chargers that can handle all twelve batteries at the same time Most chargers handle only four to eight cells at a time taking two to three days to recharge a complete set of NiCads If vou can recharge all twelve cells at once you plug it in in the evening and you re ready to go the following morning The diagram shows a simple but effective charger circuit that will handle up to twelve cells simultaneously It needs no regulation or control because it trickle charges any type of NiCad You can even leave it plugged in con tinuously without fear of damage to the cells thereby insuring the NiCads are always in a state of full charge The p A c 50 Side view of author s CB transceiver shows two inputs one for charging internally contained Nicad batteries charging current is 40 to 50mA regard less of the number of cells in case some become defective or their state of discharge From full discharged to fully charged the charging current is always a safe 40 to 50mA Use These Parts Excepting the cabi net if vou select surplus components the whole thing will cost less than 8 If you buy ali new you ll run up un necessary expense which have no effect bearing on the performance Transformer Tl is 24 to 28 VDC at no less than 100 mA It doesn t have to be more than 100 mA Don t waste your money on a high current filament trans
181. nitron receiver Mod el VTU 400 projects color images onto a 40 inch diagonal curved screen via a lens mitror arrange ment The projector section of the KP 4000 folds down for operation and conveniently folds up and out of sight when not in use shutting off all power in the receiver auto matically A roll top cover slides down to conceal and protect the pro jection screen from dust and dam age Worldwide Entertainment Sys tems Theatervision is the overall name for this firm s all in one pro jection outfits priced at 1 995 in a choice of rosewood walnut or off white paint finish less optional speaker svstems at 200 each for Continued on page 93 ELEMENTARY ELECTRONICS March April 1977 The VideoBeam Model 750 has a 3 tube projection assembly which accounts for the system s brighter picture video projection system complete with notations on furniture place ments and measurements of room borders and available space The Appeals of Projection TV Video projection systems in their present form can really hook you to TV They are in essence a TV addicts dream come true And for many movie buffs they are also a dream come true And that s why they re often called a dream ma chine Typical of user s comments is one to the effect that My projec tion system saves me a lot of money I go to the movies at home An other runs like this My set will pay itself off within two three
182. noise blanker circuits Of course if the transceiver doesn t have ANL and noise blanker on off switches its next to impossible to judge if the noise limiter circuits are having any effect on the test signal The final feature of the RF section is a 455 kHz oscillator with its separate output level control and banana jacks This osc llator is intended for service work and checkout of PLL transceiver circuits It can be used separately or in conjunction with the 27 MHz output On the left side of the cabinet you ll find the signal generators modulator control and metering A rotary switch selects modulating frequencies of 400 1000 or 2500 Hz or external modula tion for the RF output Banana jacks are provided tor connecting the external modulation signal A Modulation Am plitude control sets the percent modula tion from zero to 100 The exact de gree of modulation is indicated by the percentage of modulation meter The meter has in addition to the percent modulation scale an O to 5 calibration which represents 0 to 5 kHz Two LED lamps associated with the O to 5 kHz scale indicate above and below the channel frequency Finally a Delta control determines the meter reading which indicates how far off frequency the RF output has been 82 L2 EN EU 4 AMPLITUDE A it ll j Metering of modulation is all or delta tuning is chosen below meter tion Amplitude control adjusts carrier m
183. o it tells ail about their new auto FM redio signal booster eliminates signal fading 353 MFJ offers a free catalog of amateur radio equipment CW and SSB audio filters electronic components etc Other lit is free 354 A government FCC License can help you qualify for a career in electronics Send tor infor mation from Cleveland Institute of Electronics 355 New for CBers from Anixter Mark is a colortul 4 page brochure detailing their line of base station and mobile antennas including 6 models of the famous Mark Heliwhip 356 Send for Continental Specialties new bread boarding prototest devices They vary in prices from a mini budget kit at 19 95 Featured is the new logic monitor giving information on what i does how it works and how to use it 357 Dage Scientific Instruments offers a 16 page booklet on how to build an electronic therrhometer with control Included is an introductory course on thermocouples schematics and many applications 358 PixTronics announces its new Modal 200 Super Sensitive Electronic Darkroom Exposure Meter used to determine the correct exposures of all black and white and color negatives Useable with any eniarger 359 Electronics Book Club has literature on how to get up to 3 electronics books retailing at 58 70 for only 99 cents each plus a sample Club News package March April 1977 E ret eee m I NE e n eee H W I Box 1849 G P O Void After August 15 1977
184. o discover trouble spots and learn how to fix them CIE offers a number of laboratory courses where you learn Electronics by doing it yourself You work with your own hands on electronics components and lab equipment This combination of head and hands learning ocks in your understanding of the crucial principles you ll use on the job in your new career And you do it all at home in your spare time at your best study pace CIE s out standing lessons allow you to progress step by step An instructional technique time tested for over 40 years of special ized electronics independent home study training Importance of an FCC License and our Warranty If you want to work in commercial broad casting television or AM or FM broad casting as a broadcast engineer federal law requires you to have a First Class Radiotelephone License Or if you plan to operate or to maintain mobile two way communications systems micro wave relay stations or radar and signal ing devices a Second Class FCC License is required Even if you aren t planning a career which involves radio transmission of any kind an FCC License is valuable to have as Government certification of certain technical skills It s a job credential rec ognized by some employers as evidence that you really know your stuff To get an FCC License you must pass a licensing exam administered by the government And we are confident you can successfully ear
185. odula 2 per cent External modu lation can be applied through the banana jacks below the modulation selector switch adjusted Here s how it works Pulling on the Delta control activates electronic correction of the RF oscillator s output frequency If the control is adjusted so the meter indicates say 1 kHz with the LED illuminated the RF output fre quency is 1 kHz higher than indicated by the channel selector For example if the channel selector is set to 27 065 MHz the actual output frequency will be 27 066 MHz If the delta control is adjusted so the meter reads 1 kHz with the LED indicator lit the generator s output frequency is 27 064 MHz The delta electronic frequency correction RF GENERATOR SHIELDED ATTENUATOR Bottom inside view shows double shielded RF generator section to prevent radiation 90 MODULATION ADJUST 0 MODULATION DELTA METER METER SELECT MODULATION DELTA J can be used with or without modulation of the RF carrier so it allows measure ments of a receiver s delta clarifier or fine tuning SSB receiver sensitivity and SSB opposite sideband suppression The important thing to bear in mind is that while the B amp K 2040 replaces a bench full of test equipment it is easier to operate than just one standard sig nal generator when it comes to making CB tests and measurements We have replaced much of the test gear in our own CB lab with the
186. ols 327 Avanti s new brochure compares the quality difference between an Avanti Racer 27 base loaded mobile antenna and a typical imported base loaded antenna 328 A new free catalog is available from McGee Radio It contains electronic product bargains 329 Semiconductor Supermart is a new 1977 cata log listing project builders parts popular CB gear and test equipment It features semiconductors all from Circuit Specialists 330 There are over 450 electronic kits described in Heath s new catalog Virtually every do it yourself interest is included TV radios stereo amp 4 channel hi fi etc 331 E F Johnson offers their CB 2 way radio cata log to help you when you make the American vaca tion scene A selection guide to the features of the various messenger models will aid you as you go through the book 332 If you want courses in assembling your own TV kits National Schools has 10 from which to choose There is a pian for Gls 333 Get the new free catalog from Howard W Sams t describes 100 s of books for hobbyists and technicians books on projects basic elec tronics and related subjects 334 Sprague Products has L E D readouts for those who want to build electronic clocks calculators etc Parts lists and helpful schematics are included 335 The latest edition of the TAB BOOKS catalog describes over 450 books on CB electronics broad casting do it yourself hobby radio TV hi fi and
187. on s Box 1432 Oxnard CA 93030 NEW Lifetime Trophies Family Wedding Birth Graduation Walnut metal made Don s Place 2M 2938 North 90th Street Milwaukee W1 53222 400 WEEKLY POSSIBLE Clip newspapers stuff envelopes Proven program Send stamped addressed envelope E MASON Box 9473 P3B Fresno CA 93792 AMAZING Profits stuffing envelopes Details Free Star s 160 Harmon Somerset MA 02726 GET INTO BROADCASTING Become DJ engi neer Start own CABLE FM station get free tapes records Free booklet Broadcasting Box 5516 GC6 Walnut Creek CA 94596 1 000 00 MONTHLY possible stut ng envelopes National Box 4314 Baltimore MD 21223 BORROW MONEY No credit check 7 little known secret ways 2 00 Lee Enterprises 6501 North 8th Fresno CA 93710 NEW Plan reveals secret of envelope stuffing write International 1256 N Kingsley 3 LA CA 90029 CIRCULAR Mailers make So can you Write Gaylord 1738 SE First Rochester MN 55901 EXCLUSIVE money making info Free details Evans 1165 S 86th KC KS 66111 to MAKE 1 000 MONTH MAILING LETTERS Stamps details Diamond Rt 1 Box 137 Diamond MO 64840 EASY Money stuffing envelopes Details free Brightman 401 S Rampart LA CA 90051 DIFFERENT stuffing envelopes secrets Details free Holder 940 Nason Rossville GA 30741 STRIKE it rich Let 10 00 cash orders fill your m
188. ons Inc 2160 Patterson St Cincinnati OH 45124 X Rated DX Perhaps according to several in Frendx the listeners quoted Swiss Broadcasting Corporation European and Overseas Services Here s a free sticker from the Swiss Broadcasting Corporation you can have for nothing It s free See text for details bulletin of the North American SW As sociation Richard Wood and Kim A El liott told about hearing four letter words in profusion on Radio Sweden s incredible Saturday Show The program featured a Satirical skit on the subject of fermenting manure to produce methane gas for fuel Even the title of the humorous sketch was such that I can t reprint it here According to Wood himself a linguist the feature was spoken in authentic pseudo peasant accents Elliott observes that Radio Sweden s Saturday Show is certainly not for everyone but adds the skit was very well done Elliott also noted that Radio Finland Its Saturday show is similar to the Swedish effort with a heavy larding of well done satire For Radio Finland you might try 15 110 kHz at 1330 GMT for Radio Sweden 9 695 at 0230 GMT but there are other times and frequencies as well Anyone For a Freebee How about this attractive sticker SBC the Swiss Broad casting Corporation is offering this color ful sticker to anyone who writes to ask for it Write to the SBC European and Over seas Services CH 3000 Berne 15 Switzer l
189. ons are 40 in high x ll in wide x Il in deep The foam grilles which protect the speaker drivers on adjacent sides of the column snap off to provide access to the speaker openings pre cut iw the cabinet Similarly the bottom of the cabinet has a pre cut opening for the combination crossover and high fre quency control switch The cabinet is 51 CB Battery Charger ten batteries equals a fresh power pack of I5 VDC But NiCads only deliver t 2 volts so twelve batteries are re quired to produce 15 VDC The two extra NiCads fit in place of the filler So in order to use NiCads your set must provide room for twelve rather than ten cells There must also be a jack on the side of the transceiver to which a charger can be connected If you have both these conditions space for twelve cells and a charger jack vou can use NiCads The only excep tion to this rule is a few models which cannot accept NiCads because some NiCads are very slightly longer than a standard penlight AA battery or the CB set manufacturer did not allow for the extra size even though he provided a charger connection Make certain vour hand held set will accept NiCads before you buy them Really Low Cost Finally you need a NiCad charger and that s where you can spend real money but really One of the top instrument companies charges 30 for a NiCad charger you can build for less than 8 They get this exorbi tant price because they manufacture o
190. ooks Checked above m 3 lenciose send posipaid Please invoice on 10 day FREE trial a a Mame Phone a 4 mpan Company n Address E See B L City Sile N SAVE POSTAGE by ramitting with or dar Foreign add 10 Pa residents add cc 37 CIRCLE 14 ON READER SERVICE COUPON CIRCLE 32 ON READER SERVICE COUPON vided up to 1000V on the ohms 1500V on the voltage ranges and 3A on current shunts An optional battery pack provides 8 hours operation on an overnight charg ing Batteries also charge when the Model 283 is used on 110 VAC line For addiitonal information write to Myron Bond B amp K Precision 6460 W Cortland Chicago IL 60635 FM Wireless Intercom Radio Shack s 2 channel 3 station FM wireless intercom is a convenient home or office communications system Called the SelectaCom it works on frequency modulation FM to provide interference free sound An adjustable squelch control like on your CB on the rear of each unit eliminates background noise when they are not in use Each SelectaCom unit has a volume on off thumbwheel control and a red LED pilot lamp which glows while the unit is on A selector switch lets you operate on either channel A or B Located just above the talk bar is a call lever which can be used to beep the other stations The talk bar can be locked on for use as a remote babysitter or monitor Each unit can be moved easily from room
191. orizontally across the scope during its rise time When the sawtooth decays the beam immediately returns to the starting point on the left Other Preparatory Settings So far you have learned how to set the Intensity and Focus controls for proper brightness and sharpness of the waveform on the screen A steady pattern has been obtained by setting the Coarse Freq and Vernier controls of the sweep oscillator stage for a steady uniform pattern If the pattern looks like either of the following you are ready to proceed with an analysis of the waveform Proper Waveform Displays A B However you may obtain patterns that appear simi lar to these Which contro would you adjust to correct the pic ture labeled A Which would you adjust to correct the ELEMENTARY ELECTRONICS March April 1977 IN ELECTRICITY 1 amp ELECTRONICS RECOMMENDED THEORY FOR ALL CB OPERATORS This series is based on BASIC ELECTRICITY ELECTRONICS Vol 4 published by HOWARD W SAMS amp CO INC USING THE OSCILLOSCOPE HAT YOU WILL LEARN You will learn how to W turn on and operate an oscilloscope You will see how the scope can be used to check test points in electronic circuits in order to find possible failures or malfunctions of circuits stages or com ponents You will see how displaying on the scope the waveforms of signals in working circuits can reveal whether a circuit is working properly on or not fn addition the scope can measure
192. osed circuit loop and Reset control It is recommended that sockets be used for the integrated circuits This makes it easy to solder to the board without endangering the integrated circuits with the iron s heat It also will permit you to remove cach IC in the event the circuit ever needs servicing Once an IC is soldered into a printed circuit board it is extremely difficult to remove Be sure to insert the ICs into the sock ets or board in the correct direction Pin 1 of each IC is marked on the IC itself as well as on the copper foil side of the printed circuit layout About the Circuit B F Brain uses two integrated circuits ICI is a four section 2 input NOR gate constructed in COS MOS Complimentary Sym metry Metal Oxide Semiconductor form The advantage in using COS MOS integrated circuits is the extreme ly low current drain of the chip The CD4001 chip IC used in this circuit draws only 5 microwatts of power from the 12 volt supply A NOR gate is a digital building block which obeys the following rule If the voltage at either input terminal or both input terminals excecds 70 percent of the supply voltage the out put voltage falls to zero If the input voltage to both input terminals is less than 30 percent of the supply voltage the output voltage rises to the supply voltage Input voltages between 30 and 70 percent of the supply voltage have no logic definition and are not con sidered legitimate voltages w
193. our DEGREE by correspondence while continuing your pres ent job No commuting to class Study at your own pace Learn from complete and explicit lesson materials with additional assistance from our home study instructors Advance as fast as you wish but take all the time you need to master each topic Profit from and enjoy the advantages of independent study The Grantham correspondence degree program in electronics is comprehensive It begins with basics written in very simple language and continues through the B S E E degree level Throughout the entire program heavy empha sis is placed on clear explanations written in great detail progressing from the simple to the com plex in easy steps Our free bulletin gives complete details on the curriculum the degrees awarded the require ments for each degree and how to enroll GRANTHAM SCHOOL OF ENGINEERING 2000 Stoner Ave Los Angeles CA 90025 Telephone 213 477 1901 Worldwide Career Training thru Home Study Mail the coupon below for free bulletin pL l l ll l l l l l l l l lI l l lI 2 E Grantham School of Engineering zz 5 77 2000 Stoner Ave Los Angeles CA 90025 I have been in electronics for years Please mail me your free bulletin which gives details con cerning your electronics degree programs l Naio ss Address aT ne e E ee AQ ee ee a a a a ee a a a ic CIRCLE 8 ON READER SERVICE COUPON NO E
194. our ears Ihe Digital Channel Selector shows you the channel you re on in large LED numerals that can be read clearly in any light There s also switchable noise blanking to reject short pulse noise other systems cant block The built in power of DynaMike Plus Automatic noise limiting and Delta Tuning for clearer reception And the added protection of Cobra s nationwide network of Authorized Service Centers with factory trained technicians to help you with installation service and advice The Cobra 29XLR It has 40 channels And it has what it takes to improve communications by punching through loud and clear cn every one of them That s the beauty of it gA C obra Punches through loud and clear Cobra Communications Products DYNASCAN TR 6460 W Cortland Eh Chicago I linois 60635 ure EXPORTERS Empire A NY ESO Atlas Electronics Toront CIRCLE 24 ON READER SERVICE COUPON Cobra 29xin SWR CB CAL 9 4 S RF oorr D A RE GAIN On ATUNE elementary electroni March April 1977 Volume 17 No 2 39 49 59 68 XX 47 72 75 79 80 66 yx 43 71 32 77 51 81 16 20 27 c 55 73 89 SPECIAL FEATURE TV Sets of the Future projection TV for your home is here YOU BUILD IT CB Battery Charger Saves recharge Nicad cells for air time on pennies a day Mod X simplest digital clock you can build Foil Your Local Burglar build B F Brain for burglar an
195. outputs are relay closings directing the trains and their speed while also controlling crossing lights and audio signals Other applica tions for KIM 1 could be its use as a 56 light color organ or as a robot finding its way through a maze as it responds to audible signals As you can readily see possible applications of the micro processor as a controller are nearly end less A simple program can frequently replace dozens of interacting relays And a small change in the program will make your gadget behave in a com pletely new and diflerent way Just try to duplicate such changes with a sol dering iron and you will really start ap preciating the microprocessor KIM 1 As Universal Game Machine In spite of all the serious sounding pa pers given at computer conferences around the world the main micropro cessor application at present for the hobbyist is to play games The simple input output mentioned in the previous paragraph makes game playing with KIM 1 real child s play Both the key board and the LED displays are con nected to the microcomputer via cer tain memory locations in the same way as the previously described input out put terminals Therefore by judicious 6502 MICROPROCESSOR UNIT RANDOM ACCESS MEMORY READ ONLY MEMORY TELETYPE uus CASSETTE RECORDER INTERFACE _ programming and without need for ex ternal devices one can use the built in keyboard as a
196. ow edge of the band 4770 kHz There are many strong Colombian and Venezuelan 60M signals most evenings and one merely has to tune from fre Neiva Colombia on 4945 anan E Many stations in Latin America have QSL cards printed which they ll send you verifying your reception of their broad casts Stations without QSL cards usually will write a special letter to you like these two re ceived by the author No 3074 Bogot marso 29 de 1 954 TIONAL RADIO CLUB Box 218 Crystal Beach Ontar o Canad Muy apreciados se ores Acupamos recibo de su atento report da re geet en d de neat ri emisora fechado wn octubre l7 del a o Pr xi Pasado por lo cual le e5tamos muy egrade idos Al respstto nos permitimos comuni SRENSe que hemos encontradjo correctos tulas repor Tenemos mucho gusto de rowitirias con la presente un gellardets de nuestra emisora Y sin otro Partt cular nos suacribim s de ustedes Stentos servidores RADIO CADi eps a LT Lia ZmisQge Murva Granjedu 126 J9SE J MOLINA vintni redo Antique Radio Corner Continued from page 71 East Bloomfield Museum We ve visited the AWA communications mu seum at East Bloomfield NY again We visited there two years ago when they were just beginning to work on the building Now there are hundreds of historical radios wireless equipment horn phonographs and early TV re ceivers Outstanding is the vacuum tube display Some
197. ow to use oscilloscopes Literature Library yx Cover Feature CB STUNTS THAT YOU SHOULDN T KNOW ntary alid MEMBER T to ere NS pura INSTITUTE OF zm m HIGH FIDELITY AUTHORS IN THIS ISSUE Anthony Caristi James A Fred Herbert Friedman Don Jensen Herman Johnson Kathi Martin Norman Myers Hank Scott C M Stanbury and the ELEMENTARY ELECTRONICS Editorial Staff Illustration by Ron Macarthy ELEMENTARY ELECTRONICS March April 1977 THE STAFF Editor in Chief and Electronics Group Coordinator Julian S Martin WA2CQL Technical Editor Charles Graham W1HFI 2W3175 Communications Editor Morgan Godwin WAWFL KCR6444 Audio Editor Christine Begole KFC3553 Citizens Band Editor Kathi Martin KGK3916 Workbench Editor Hank Scott Editorial Assistant Sandra Barack Art Editor Ralph Rubino Assistant Art Editor Augustus Ginnochio Cover Art Director Irving Bernstein Art Assistants Robert Modero Caroline Imperato John Neely Joni Erlon Advertising Director David J Miller KCX1268 Advertising Research Associate Jyll Holzman Production Director Carl Bartee Production Editor Geri Brakatselos Newsstand Circulation Director Don Gabree Subscription Circulation amp Marketing Director Robert V Enlow Director of Market Development James C Weakley President and Publisher Joel Davis Vice President and General Manager Leonard F Pinto Vic
198. owing 256 possible values per byte In hex nota tion 00 through FF covers these 256 values The data can be written or any address can be selected via the key board which has the hex characters 0 through 9 and A through F right on it Control of the data flow between the microprocessor and the outside world is via two MCS 6530 chips which have 1024 locations of read only memory ROM These ROMs have been pre KIM 1 connects to KIM 4 motherboard permitting plug in of up to six more boards for memory expansion CIRCLE 73 ON READER SERVICE COUPON ELEMENTARY ELECTRONICS March April 1977 MPUTER READOUT by Norman Myers Computers Editor programmed by MOS Technology They contain Monitor and Executive pro grams that control display of the digits on the LED receipt of digits from the keyboard and even allow a teletype TTY or an ordinary cassette tape recorder to be used with KIM 1 The cassette unit is very easy to connect and lets you write programs from the KIM 1 memory onto your tapes and vice versa Fantastic This ability to write save and recall programs and even data opens up hundreds of possi bilities You can save programs forever and reload them into your KIM 1 in seconds The next question of course is what can be done with this micro magic device What To Do With It You may first think that the main function of a com puter should be to crunch numbers that is add subtract multipl
199. p Editor ELEMENTARY ELECTRONICS 229 Park Avenue South New York NY 10003 have wider variations in their firing volt ages than the ones in the author s proto type which we tested in our lab To be sure the neon fires correctly add three 300 000 ohm resistors any wattage to the circuit One across each neon bulb That ll Straighten it out Good testing Wants More Juice Is it possible to increase the charging capacity power of one six twelve volts battery charger P C Trujillo Alto PR I d say no The transformer is designed for a certain maximum current To re place it would require a large expense Also the meter rectifiers and possibly the in ternal wiring must be replaced It s easier to buy a new unit The Law Has Ears Is it illegal to tape program material off TV and radio programs D D Little Chute WI If you record for your own personal use the answer is no You may play back the material for your viewing or hearing and include your immediate family in your home However do not attempt to sell the material or use it to entertain others For example a restaurant owner recorded some musical programs and played it back for his patrons to enjoy while they ate You guessed it h was sued and lost in court Just keep it to your self and no one will or can complain MHz to kHz Could vou tell me how to convert kHz frequency numbers into MHz numbers because all the radios come across are in
200. part number 962 9302 Allied Electronics see below for address R2 300 ohm 10 watt resistor part number 962 9270 Allied Electronics S1 2 3 Single pole momentary On switch normally open Radio Shack 275 1547 or equiv S4 SPDT toggle switch Radio Shack 275 326 or equiv T1 120 VAC primary 24 26 VAC 300 mA secondary power transformer Radio Shack 273 1386 or equiv T2 120 VAC primary 6 VAC 300 mA secondary power transformer Radio Shack 273 1384 or equiv DI o T2 A igen i sal be 20V ALARM DISPLAY FAST SET SLOW SET ALARM SWITCH Q1 NPN general purpose transistor Radio Shack RS 2009 or equiv Misc Fuse holder panel type for Fl Radio Shack 270 364 or equiv Buzzer for alarm 3 volt type Radio Shack 273 004 or equiv Aluminum wood look cabinet 234 x 6 x 4 inches or larger Radio Shack 270 260 or equiv AC line cord available at hardware stores wire hard ware solder etc ADDITIONAL PARTS FOR CLOCK OPTIONS 5 6 7 Switches same as S1 2 3 above for Hold Cat nap snooze or Seconds Display options To obtain the clock module and specifica tion sheet write to Digi Key Dept E Box 677 Thief River Falls MN 56701 Ask for Mod X MA1002A Price is 11 55 plus 75 cents for postage and handling Minn resi dent add 46 cents state tax Order module before other parts to be sure of module availability at this price Allied Electronic s address i
201. pecial input output locations are treated by the microprocessor as if they were regular memory locations The data in these locations can be read and manipulated by the program in the microprocessor KIM 1 is an 8 bit machine therefore 8 pieces bits of information can be extracted from each input output lo cation One of these specia locations appears on 8 pins of the KIM 1 con nector If for example decimal number 5 is stored 00000101 in binary in one of these special locations a positive voltage would appear on pins 2 and 0 and ground would appear on the remaining 6 pins associated with this location Similarly one can use the same connector for inputting Is and Os to memory by applying appropriate voltages to the pins A code word in another special location in memory de termines which connector pin is the input and which is the output of the computer Voltages on the KIM 1 con nector pins can be used to control lights turn relays on and off and thus do anything which can be operated by an electric sequencing motor A read ing or writing instruction takes only a few microseconds so KIM 1 can al ternately process input signals arriving via input leads and quickly issue com mands via output leads A built in crys tal controlled timer further increases the microprocessor s usefulness A typical application would be an elaborate model train control where in puts consist of position sensors arid manual switches while
202. power devices The book supple Soft cover 429 pages 6 00 ments the data and aplication note ab stracts on RCA standard type integrated circuits and power devices contained in the 1 232 pages of the two volumes in the SSD 200D series High Reliability Devices may be ordered from RCA Solid State distributors Or by sending check or pur chase orders to RCA Solid State Division Box 3200 Somerville NJ 08876 In the Air A new 406 page volume Aviation Electronics Handbgok by Ed ward L Safford is a complete simplified guide to aviation electronics for radio mechanics avionics technicians and pilots From the smallest puddle jumper to the biggest jumbo jet all planes depend on transistors tubes and integrated circuits to do their jobs safely and efficiently This Continued on page 18 ELEMENTARY ELECTRONICS March April 1977 a amp Loosely translated that s CB talk for Sparkomatic has CB twin trucker antennas CB base station antennas CB instant mount antennas like magnet mount and clip ons CB motorized and manually operated disappearing antennas CB indoor and outdoor public address speakers CB external speakers with tone purifiers CB external speakers without tone purifiers and CB converters Not to mention a complete line of 40 channel in dash and under dash mobile transceivers and base station units Including 40 channel guy TM transceivers with memory control buttons f digital eadouts and oth
203. pro ducing sideband splatter 30 kHz either side of the operating channel Imagine how much worse it is when the level control is turned up 79 e 2 DXing Colombia quency to frequency and listen for the ID As a general rule Colombian fre quencies on this band end in 5 and Venezuelans with a 0 Unfortunately this arrangement does not hold above 5 MHZ Government Stations In addition to the privately owned broadcasters men tioned above both governments oper ate stations called Radio Nacional When its 4955 kHz channel is active this is by far the easiest frequency upon which to log R Nacional de Colombia RNC is most notable for the number of other international broadcast stations it relays including KGEL a privately owned missionary station near San Francisco This is unusual because no international missionory stations are al lowed to operate from Colombia itself R Sutatenza s transmissions are in tended only for domestic reception RNC s operations on 4955 are er ratic but R Nacional de Venezuela s 60M channel 5020 kHz has been silent much longer RNV notorious in DX circles for issuing ambiguous informa tion on its frequencies and locations claims to operate only two transmitters on 6170 amp 15400 kHz However it is known that they have access to short wave facilities of the Venezuelan na tional telephone company CANTV which means RNV can activate addi tional channels whenever nece
204. pro ject a correspondingly brighter pic ture than a system using an old TV representing an earlier state of the art Among favorite sets used by major video projection svstem sup pliers are models from Sony and Toshiba using the Trinitron and Blackstripe picture tube concepts respectivelv These are noted for their brightness and sharpness Another consideration is conven fence If vour TV has a remote con trol that control will be a boon when operated as part of a video projection system In Conclusion No home enter tainment source can be regarded as totally divorced from the other en tertainment sources available in to ELEMENTARY ELECTRONICS March April 1977 Non day s homes The hypnotic TV tube shares available family time with the high fidelity system and very often they share space in the same room It is possible that with time projection TV will become wedded to both home video recording svs tems and high fidelitv svstems The result will be one all encompassing multi media home entertainment center which will hold possibilities for audio and video reproduction in the home which are now bevond the grasp of the human imagination Speculation about the future is in the end just that speculation Only one thing s certain projection TV is a step toward the future and chances are good that its ramifications will be felt throughout the home enter tainment field including that of high fidelity i CB
205. quency range Linear and Log Sweep Cal ibrated attenuator VCO for External Frequency Control BNC Front Panel Output Wired 169 95 EICOCRAFT IC KITS EC 5000 SCA ADAPTOR KIT ONLY 12 95 Convert your FM radio or receiver to pick up the official FCC licensed background music service SCA IC decoder adaptor permits hearing uninterrupted commercial free music broadcast by many FM stations For personal non commercial use only IC PROJECT KITS NOW AVAILABLE EC 5100 ESP Tester 10 95 EC 5200 Decision Maker 9 95 EC 5400 Stereo Power Amplifier 10 95 EC 5500 Stereo Pre Amp 9 95 EC 5600 Electronic Lock 11 95 EC 5700 Universal Power Amp 8 95 BURGLAR FIRE ALARMS S 500 BURGLAR FIRE ALARM SYSTEM Professional Security System designed for easy do It yourself installation Features EICO FC 100 Control Center with AC DC automatic transfer to battery operation Complete system includes Installation Handbook Add additional sensors bells to suit your own needs 159 95 SD 75 BATTERY OPERATED FIRE SMOKE ALARM lonization type detector gives earliest possible fire warning Mounts directly to ceiling with 2 screws Beeps when battery needs replace ment U L listed 39 95 EICO s 30 Years Experience Assures More Electronics Value For Your Money CB ACCESSORIES EICO 700 CB FREQUENCY COUNTER Compact in line mobile frequency counter for the serious CB er Hobbyist Operat
206. r In the late These are just a few of the ancient vacuum tubes to be seen at the AWA s Museum 1920 s the Mills Novelty Company in troduced a model that had the record holders arranged like a paddle whee or as it is Sometimes called the Ferris Wheel model The first one that I re call offered eight selections of 78 RPM records and used a telephone dia as a selector The cabinet was massive and usually made of oak Some models had leaded glass windows in front so you could watch the mechanism operate It wasn t long before 12 selection model appeared The Mills Novelty Co based in Chicago Illinois didn t stay in the music machine business too long and soon began making slot machines vend ing machines pinball machines etc There is a very active market for these old amusement machines and juke boxes If you run across any of these machines that are reasonably priced pick them up If you don t want to collect them yourself you can trade them for tubes radios speakers etc for your radio collection As the radio electronic scene shifts from the experimenter building his own equipment to the hobbyist who buys only ready to play equipment the old established companies keep dropping product lines that they had manufac tured for many years The Yaxley Manufacturing Company was founded in 1916 and became a division of the P R Mallory amp Company Inc in the early 1930s One of the lines of radio parts made in t
207. r TV Test Insiruments 256 p 230 il 5 95 B CJHome Cai TY Repair Guide 144 p 20 i 395 E CJPinooint TV Troubles in 10 Minutes 327 p 394 il 5 95 z CB Schematic Svcing Manuals each ZUU p 35 95 LJ VOI 1 Kris Browning Hy gain Penney s O Voi 2 Teaberry Unimetrics H Pearce Simpson Siltronix C Vol 3 E F Johnson SBE Linear g Sonar Royce C Vol 4 Pace Fanon Courier m O 2nd Class FCC Encyciopedia 602 p 445 it 7 95 E C Complete Shortwave Listener s Hdbk 288 p 101 il 6 95 E OCB Radio Operator s Guide 2nd ed 256 p 139 il 5 95 B C How to Hear Speak CB In a Short Short 172 p 85 il 3 50 M C Pictorial Guide to CB Radio Install Apr 256 p 304 il 5 95 M practical CB Radio T shooting amp Repair 238 p 108 i 5 95 M OCompiete FM 2 Way Radio Hdbk 294p 111 il 6 95 Z JAmal FM Conversion Constr Projs 256 p 187 il 5 95 B C Bocsi Annc r 3rd Class FCC Study Guide 168p 19i 3 95 B How To Be A Ham incl Latest FCC Rules 192 p 25 il 3 95 gy JCommercial FCC License Handbook 444 p 150 il 5 95 mg C The 2 Meter FM Repeater Circuils Hdbk 312 p 19411 6 95 W CJRTTY Handbook 320 p 230 il 695 E C Citizens Band Radio Service Manual 228 p 84 il 5 95 B AMATEUR RAOIO STUOY GUIDES O Novice 5 95 C General L 7 95 O Advanced 5 95 C Extra 5 95 O Incentive 4 95 241 i M S CJHow to Read Electronic Circuit Oiagrams 192 p 140 il 4 95 O21 Simple Trans Radios You Can Build
208. r equiv R2 10 Megohm Y2 watt resistor Radio Shack 272 000 or equiv R4 1 Megohm V watt resistor Radio Shack 272 000 or equiv R6 9 11 10 000 ohm 12 watt resistor Radio 272 000 or equiv R8 820 000 ohm Y2 watt resistor Radio Shack 272 000 or equiv R10 100 ohm watt resistor Radio Shack Shack 272 000 or equiv R12 47 000 ohm 12 watt Shack 272 000 or equiv C1 see text C2 01 uF capacitor Radio Shack 272 131 or equiv C3 2 2 uF 15 VDC electrolytic Radio Shack 272 1407 or equiv C4 001 uF capacitor Radio Shack 272 126 resistor Radio Capacitor 12 VOC _ Cl T 20 000uF D2 PARTS LIST FOR B F BRAIN ALARM C5 150 uF or larger 20 VDC electrolytic SPEAKER capacitor Radio Shack 272 1017 or equiv C6 47 uF 35 VDC capacitor Radio Shack 272 121 or equiv I 1 CD40001 COS MOS Integrated circuit Radio Shack 276 2401 or equiv 102 555 timer integrated circuit Radio Shack 276 1723 or equiv Qi 3 Motorola 2N3906 PNP general purpose amplifier transistor Radio Shack RS2021 or equiv Q2 NPN power transistor Motorola 2N3771 40 or more volts 10 or more A Misc Alarm bell Radio Shack 275 498 or Radio Shack 273 020 or equiv fire sensors Radio Shack 275 506 or equiv window foil Radio Shack 275 502 or equiv window foil connectors Radio Shack 275 504 or equiv contact switches Radio Shack 275 495 or equiv perf board or
209. r speaker Opening and four retaining screw holes Not shown here are four holes spaced between the speaker retaining screw holes which are for the self tapping or wood screws which hold the Masonite to the plastic piece PLASTIC FLANGE PART OF COVER USE SPEAKER TO LOCATE HOLES ELEMENTARY ELECTRONICS March April 1977 Ta Here is an unusual loudspeaker sys tem that employs a two gallon food jar the kind usually called a cookie jar as the enclosure for a small loudspeaker system Depending on the particular driver speaker unit you use you can get high fidelity sound from this very com pact speaker system or you can use a less expensive speaker and still get very pleasant sound for background music or mostly listening to talk programs at high sound levels Since the enclosure is made of clear glass it can be used as a terrarium for display of an artificial floral arrange ment or a miniature garden Or favorite pictures and photographs can he mounted to the inside surfaces with glass insulation filling between similar to the display made by a photo cube Another idea the enclosure can be decorated by filing the inside with small cut cubes of fiberglass Fiberglass insulation is available in shades of yel low and pink White cotton balls can also be used for additional color variety Construction You will note in the illustrations that the speaker driver is positioned in the neck of the enclosure a
210. r speed 14 gallons hour fuel consumption 245 true course and 80 nautical miles distance Takeoff will be at 12 50 p m After performing calculations based on that information and the data in the program the calculator in a few sec onds will show a true heading of ec eos C PH He 9 4 pool FH 0 235 0863 in its display or print it out on paper if an optional PC 100 printer is attached Further program runs will show 223 0863 magnetic heading 93 4838 ground speed 0 5121 estimated time enroute 11 9807 fuel consump tion 13 4121 estimated time of arrival The sequence of computations is re peated for each flight leg After the second leg is calculated the program also provides the pilot with running totals of certain information like total time in flight and overall fuel consump tion Several flight plan programs are eeeee Sewer ot ere Fe eB et 88 CO ILI Ls ed in solderless breadboarding our SK 10sock et above for 17 75 and we ll also give you our SK 20 sock et as a bonus Not only that but if the SK 10 doesn t live up to your expec tations return amp it for a full re fund and keep the SK 20 for your trouble E amp L sockets are the finest made in the industry and have a life of over 10 000 insertions Integrated circuits and dis Pd E E amp L INSTRUMENTS INC 61 First Street Derby Conn 06418 203 735 8774 Telex No 96 3536 hm a cee ae
211. r the regu lated voltage can vary by 10 or 40 20 The prices vary inversely as if you build only the B battery you ll have plenty of room inside 43 EF TV Sets of Future ing it onto the viewing screen Ac cording to one knowledgeable in dustry source the immutable laws of optics prevail in the matter Said he Light in passing through lens es loses its brightness There s a for mula the size of the lens nature of the lens focal length etc and the results are calculable You will never get more than 25 or 30 per cent of the brightness of the TV set you re using Some lens assemblies collect less than five percent of the light on the tube face Some companies are looking to fresnel optical svstems as the an swer It is claimed that plastic tres nel lens are able to collect a far greater amount of light perhaps as much as four times that of glass lens assemblies now used in video pro jection systems A major problem at least at the moment is that fres nel lenses are hard to fabricate in large sizes at prices the average con sumer can afford The lack of picture brightness is somewhat of a nuisance In order to get the most out of a video projec tion outfit vou must operate it in a darkened preferably totally dark room Otherwise the picture bright ness may be less than acceptable Under such conditions the picture is faint with colors pale or with some element of the
212. r you feel they are necessary Again there is no limit to the number of sensors which can be added to the circuit Both open and closed circuit sensors may be used Inexpensive Alarm There is no need to purchase an alarm bell Any inexpen sive eight inch or larger 3 2 or 4 ohm speaker will do the job nicely The alarm circuit produces a 12 volt peak to peak square wave which will deliver 9 watts of power into a 4 ohm load This will produce sufficient sound for most applications If desired more power may be obtained simply by in creasing the supply voltage to the speak er For example if a 24 volt supply is used the power delivered to the speaker will increase by a factor of 4 to 36 watts B F Brain produces an up and down wailing sound which will com mand lots of attention even at the 9 watt level Window Protection Conductive foil for windows and doors is relatively in expensive A 150 foot roll of in ELEMENTARY ELECTRONICS March April 1977 quality cassette player A better cassette player is always wise because the extra power output and operating features will be enjoyed for thousands of miles One good buy is the unit shown in the pictures here It s Radio Shacks Realistic Model 12 1813 It features automatic end of tape reverse giving continuous play like an 8 track deck fast reverse and fast forward user re versing Select and auto start from the end of the reverse tape automatically starts fro
213. rd ed 434 p 5 95 CJ Solid State Color TV Photo Symp Guide 224 p 169i 5 95 C Beginner s Guide fo TV Repair 176 p 50 il 4 95 OT shooting With the Dual Trace Scope 224 p 252 il 5 95 C TV Troubleshooter s Hdbk 3rd ed 448 p over 300 il 4 95 O Color TV Case Histories tllustrated 238 p 219 il 5 95 OTY Schematics Read Between the Lines 252 p 188 ii 5 95 OLogical Color TV Troubleshooting 240 p 151 il 5 95 when you see B amp K Precision s Model 283 its a 3 digit multimeter priced at 170 00 that uses high intensity high reliability LED displays 0 41 in high that can be easily read in brightly lit rooms at a distance of at least six feet The 283 measures DC volts DC current AC current and resistance A special low voltage circuit permits measuring resis tance of transistor shunted resistors The Mode 283 has 100 overrange capability on four ranges so that one can read to 199 9 on a scale that is normally set for 100 0 maximum Out of range is indicated by a flashing digit and three zeros All readings have an automatically positioned decimal point Overload protection is pro CTY Bench Servicing Techniques 228 p 177 il 4 95 O Modern Radio Repair Techniques 260 p 36 il 4 95 a CO How to Interpret TV Waveforms 256 p 250 il 4 95 a QC All In One TV Alignment Handbook 304 p 145 il 5 95 m OTY Tuner Schematic Servicing Manual 224 p 287 il 6 95 g C How to Use Colo
214. ree lines 3 75 Rubber stamps B1337 Waldo Arkansas 71770 SALESMEN DISTRIBUTORS AUTOMATIC Fishhooks Profitable samples 2 00 refundable Arons 61 Mastic Beach NY 11951 SCIENCE amp CHEMISTRY FIREWORKS Spectacular novelties simplified manufacturers textbook 5 00 Guaranteed Tropic Box 95M4 Palm Bay FL 32905 SONGWRITERS SONGWRITERS Poems Songs Wanted Creative Music Productions Box 1943 A3 Houston TX 77001 EXCITING Offer Send poems songs Crown Music 1270 RX Broadway New York 10001 STAMP COLLECTING TERRIFIC Glant Illuminated Magnifier Battery operated 5 95 Satisfaction Guaranteed Kel Rico A 0510 Box 400 Anacoco LA 71403 SURPLUS EQUIPMENT GIANT Bargain Packed Canadian Surplus Catalogs 1 00 Etco Electronics DG Box 741 Montreal A WATCHES WATCHMAKING amp REPAIRING WATCH and clock repairing books tools materials Free catalog No th American Box 77 EE27 Fox Oise Grave JL 60021 MARKET Classified ELEMENTARY ELECTRONICS is published Bi monthly The rate per word for CLASSIFIED ADVERTISEMENTS is 1 25 payable in advance minimum ad 15 00 Capitalized words 40 per word additional ADDITIONAL INCOME ANNOUNCING Fantastic new homework Write Regal 10835 SE Powell 35 Portland OR 97266 3 HOURLY Stuffing envelopes Easy work Details free Mitchell Box 140398 Dallas TX 75214 250 WEEKL
215. ri zon radar in the Baltic area beamed at Canada and the U S The FCC has com plained to the International Telecommuni cation Union in Geneva Switzerland DOT vs FCC I live in Canada and want to get my CB license While am waiting for it am 1 allowed to use the CB operators temporary Now you the hobbyist can do wire wrapping professionally with our easy to use Hobby Wrap qun 025 sq post CIRCLE 19 ON READER SERVICE COUPON ELEMENTARY ELECTRONICS March April 1977 AWG 30 wire batteries not included 29 28 Learn about future 4r Fa Y DOE Lag Y 1 5 to 30 MHz Shortwave Bands 2995 Plus Standard AM Tune in the world Five controls 3 speaker AC adapter jack Includes earphone and lis tening guide Requires 4 C ceils for battery operation Includes 2 sip SOLAR POWER 1 295 MANUAL GIVES HISTORY OF SOLAR POWER AND ITS USES PLUS EASY INSTRUCTIONS FOR 25 PROJECTS Panels Harness the power of light Learn the hows and whys of solar energy as you build sun powered radios transmitters relays light beam communicator even a sound synthesizer 25 fascinating projects in all Includes solar cells transistors transformer code key 22 separate components all in a 15x10x2 work case Pre mounted parts and solderless breadboard chassis for safe sim ple neat assembly Easy to follow instruction manua explains each project in non technical lan
216. roduce the familiar siren effect To keep the standby current drain of B F Brain low the supply voltage to IC2 is normally cut off by Q3 Since in the quiescent state the voltage at pin 3 ICIA is 12 volts Q3 has no forward bias and is cut off When the latch circuit changes state Q3 receives forward bias through R12 turning on IC2 Output Circuit A two transistor cir cuit is used to drive the speaker When the alarm circuit is in its resting state the voltage at pin 11 of IC 1D is 12 volts Thus Q1 has no forward bias and is cut off Q2 base current is zero and it too is cut off The circuit of QI and Q2 therefore does not draw any current from the supply Once the cir cuit of ICIC and ICID is activated the output voltage at pin 11 ICID be comes a 12 volt peak to peak square wave This causes Ql and Q2 to switch on and off at the 1500 Hertz rate Q2 drives the speaker with the 12 volt square wave producing 9 watts of audio power A square wave output is actually more desirable than a sine wave since it is rich in harmonics This produces a more natural sounding siren If higher output power is desired the speaker can be returned to a volt age higher than 12 volts This will pro duce a peak to peak voltage across the speaker an amount equal to the higher voltage Such a connection is shown 70 SPEAKER CLOSE TO OPERATE F Ri 3 5 7 470 000 ohm watt resistor Radio Shack 272 000 o
217. rophone featuring PRM circuitry and variable gain control for matching microphone gain to the sensitivity level of the transceiver The manufacturer s suggested retail price is 69 95 Get al the facts by writing to Mura Corporation 50 South Service Road Jericho NY 11753 75 Covers All 40 A trunk mount antenna spanning all 40 CB channels comes from Antler Antennas Called the Super Broad the antenna delivers flat readings over the entire 40 channels The shallow SWR curve of the new Antler Super Broad provides a high level of performance amp L vf CIRCLE 49 ON READER SERVICE COUPON for both 23 channel units and the new 40 channel models The Antler Super Broad is a trunk mounted center loaded design The coil is tuned and sealed against moisture Fittings are chrome plated brass Whips are made of 17 7 PH heat treated stainless steel for added flexing strength and resiliency Antler antennas are sold nationwide For more information write Antler Antennas MCM Mfg Co 6200 South Freeway Fort Worth TX 76134 RF Filters for CB If you ve ever had a neighbor give you a big 10 90 you ll be glad to know about these three TV interference filters from Avanti The problem could be at the trans ceiver the TV set or in the AC power line Where determines the type filter required If the transceiver is radiating harmonics of the same frequency assigned to one or more of the local TV channels installatio
218. roved analgesic effects No 71 997 EK 89 95 Ppd Our fully transistorized BFO unit can locate a quarter at 18 Powerful 6 trans oscillator amplifier circuit Comp to others priced 50 more Alumi num just 2 Ib No 80 222 EK 39 95 Ppd EDMUND SCIENTIFIC CO 300 Edscorp Bldg Barrington N J 08007 e 609 547 3488 America s Greatest Science e Optics e Hobby Center ELEMENTARY ELECTRONICS March April 1977 164 PG CATALOG 4500 UNUSUAL BARGAINS FOR HOBBYISTS SCHOOLS INDUSTRY EDMUND SCIENTIFIC Co 300 Edscorp Bldg Barrington M J 08007 Send me the following Stock No Quantity ELM BANK AMERICARD maste charge Price Ea 1 SEND FREE f 164 PG CATALOG EK American Exp Master Chg Charge my BankAmericard Add handling charge 1 00 Enclosed is ___check ____M 0 in amount of Bm i Interbank No Card No Signature Expiration Date 30 DAY MONEY BACK GUAR ANTEE You must be satis fied or return any purchase L 30 days for full refund City State Zip LED due for GM Address CIRCLE 7 ON READER SERVICE COUPON 19 BOOKMARK book shows how these parts are assembled into all types of complex avionics systems for military private and commercial planes The unique features of aviation AVIATION ELECTRONICS HANDBOOK By Edward t Safford Soft cover 406 pages 8 95 EINEN e THE ANTI THEFT CB ANTENNA
219. rter and a control unit inter connected by a slim 25 foot plug in control cord The converter is usually located behind or under the TV set The only wiring necessary is to connect the downlead from the TV antenna into the converter and then connect the con verter output to the antenna terminals of the TV set The back of the TV set is not removed to make the installation All necessary jumper cables and accessories are supplied with the TRC 82 The re mote control may be placed anywhere in the room Extension lengths of control cord are available in case the user wants to operate the TV set from a distance greater than 25 feet The control cord is slim enough to be hidden under a rug or to run along a baseboard Direct access remote control channel changes are accomplished by a unique feature of a varactor diode oscillator its frequency can be changed simply by changing the bias voltage of the varactor This makes it possible to change channels without physically rotating a TV tuner Another advantage is that when changing chan nels you go directly to the desired chan nel without clicking through intermediate channels saving wear and tear on the tuner The Jerrold TRC 82 converts all incoming VHF and UHF channels to either Channel 3 or Channel 4 whichever is not broadcast locally After simple installation of the TRC 82 the user leaves the TV set tuned to Channel 3 or 4 The power cord of the TV set is plugged into t
220. s e p n Part ACE Tie DIP No No Board Size No Model No Points Capacity Buses Posts inches 923333 200 K kit 8 16 s 2 4 9 1625 9 16 923332 208 assern 8 16 s 2 4 9 16 5 9 146 28 95 923334 201 K mit 12 14 s 2 4 9 1627 24 95 923331 212 assem 12 14 s 2 4 9 1627 34 95 923326 218 assem 18 14 s 2 6 1 227 1 8 46 95 923325 227 assem 27 14 s 4 829 1 4 59 95 923324 236 assem 36 14 s 4 10 1 429 1 4 79 95 Order from your A P distributor today Our distributor list is growing daily For the name of the distributor nearest you call Toll Free 800 321 9668 Send for our complete A P catalog The Faster and Easier Book AP PRODUCTS INCORPORATED Box 11 0 EE Painesville 44077 216 354 2101 TWX 810 425 2250 CIRCLE 5 ON READER SERVICE COUPON J This is easy anyone can solder 433 eS ams WITH KESTER SOLDER P j m W AN S r 2 GC E Rut UH E N oom Handymen Hobbyists DO IT YOURSELFERS Let Kester Solder aid you in your home repairs or hobbies For that household item that needs repairing a radio TV model train jewelry appliances minor electrical repairs plumbing etc Save money repair it yourself Soldering with Kester is a simple inexpensive way to permanently join two metals When you Solder go First Class use Kester Solder
221. s 401 E 8th St Ft Worth TX 76102 sleep After the alarm goes off touch the Alarm button and you will be able to snooze for nine more minutes Construction Now comes the easy part building the clock Remember two things here First the clock module fits in the palm of your hand and is there fore a nice compact unit that can be mounted in almost anything from a cabinet or workbench to a wall Second if you choose not to use the alarm fea ture your project will have eight com ponents and three switches so your 60 construction time will be very short But the pleasure that comes from those few short construction hours is fantastic especially when you first turn on the power and see those big bright num bers staring back at you Play It Safe Now for safety s sake we have to get a few things straight Remember that this unit is going to be plugged in all day long day after day so be sure all your solder connec tions are good and be sure to use resis tors with the correct wattage rating so Author also built this handsome wooden case to house another Mod X clock He included optional additional functions which can be seen in the schematic dia gram in the middle of the next page they will not get too hot Be sure also that the unit is built in a safe container For example if the clock is to be in a wooden box be sure that the resistors have plenty of ventilation room around them and t
222. s latest catalog for surplus gear 308 Get Antenna Specialists catalog of latest mo bile antennas test equipment wattmeters acces sories 307 Want a deluxe CB base station Then get the specs on Tram s super CB rigs 308 Compact is the word for Xcelite s 9 different sets of midget screwdrivers and nutdrivers with piggyback handle to increase length and torque A handy show case serves as a bench stand aiso 310 Turner has two booklets on their Signal Kicker antennas They give specifications and prices on their variety of CB base and mobile line Construc tion details help in your choice 311 Midland Communications line of base mobile and hand held CB equipment marine transceivers scanning monitors plus a sampling of accessories are covered in a colorful 18 page brochure 312 The EDI Electronic Distributors Inc catalog is updated 5 times a year It has an index of manu facturers literally from A to X ADC to Xcelite Whether you want to spend 29 cents for a pilot light socket or 699 95 for a stereo AM FM receiver you ll find it here 313 Get all the facts on Progressive Edu Kits Home Radio Course Build 20 radios and electronic cir cuits parts tools and instructions included 315 Trigger Electronics has a complete catalog of equipment for those in electronics Included are kits parts ham gear CB hi fi and recording equip ment 316 Get the Hustler brochure illustrating their com plete
223. s of homes is one of the fastest in creasing crimes In many cases homes are left vacant during the day when both husband and wife work leaving an unprotected home to the mercy of thieves If you haven t been victim of such a crime yet consider yourself lucky Better yet consider electronic protection of your home There are many burglar alarms avail able for the home However a good alarm system may cost as much as 500 when installed by professionals Even the do it yourself units available from electronic supply houses or discount stores cost 100 00 and more There s no need for you to spend this kind of money to achieve home security if you are handy at building electronic circuits B F Brain can do the job a at fraction of the cost of a do it yourself kit and will be just as effective and reliable as any on the market By using modern electronic technology an extremely simple circuit has been designed which produces ex cellent performance at very low cost The circuit uses two integrated circuits which cost less than 2 00 Works Open or Closed B F Brain has several desirable features It may be used as a closed circuit in which all points of entry into the house are pro tected by a loop of conductive foil and normally closed switches There is no limit to the length of the loop or num ber of switches which may be em ployed since they are connected in series This allows protection of any number of doors and windows
224. sceiver in the closet or the trunk of your car and a sibly a thousand times If you use a week or two later they will deliver al hand held transceiver you ll break even BRIDGE ee RECTIFIER ee most full power Fast charge NiCads prototype charger Parts layout is uncritical Using terminal strip lugs as shown makes things se cure Bridge rectifier can be made up from four Inside view of author s Ness junk box diodes an aeneis ELEMENTARY ELECTRONICS March April 1977 can t hold a charge that long You Can Refrigerate Em Speaking of car trunks if you leave a hand held CB set in the trunk and the temperature plunges down near freezing ordinary penlight batteries aren t going to de liver much operating time But NiCads will still be going like gangbusters in cold weather long after standard bat teries are too pooped to pop Can your hand held use NiCads Simply look inside to tell If your hand held uses penlight AA size batteries there is probablv room for twelve cells though only ten are used a filler takes up the space of two cells Since the standard battery delivers voltage of 1 5 PARTS LIST FOR CB BATTERY CHARGER R1 220 ohm Y2 watt resistor Radio Shack 2 2 000 or equiv T1 24 28 volt power transformer rated 100 mA BRi Bridge rectifier 50 PIV 100 mA LED1 50 mA Radio Shack 276 026 or equiv JH Phono jack Radio Shack 274 1575 or equiv Includes PL1 be
225. se speakers for quadraphonic sound M fuseholder normally supplied with the player and splice it into any part of the power wire The wiring should give you no trou ble because all the wires are color coded red is the positive battery con nection black is ground and what s left usually green and brown blue grey or white are the speaker connections To play a cassette simply slide the player into the dash mount set the speaker switch to rape and pop the cassette into the player When you reach your destination and park to protect the player just slide it out of the mount and place it out of sight under the front seat or better still put it in the trunk And remember not to leave a collection of tapes on the seat as a message you have a tape player in your car amp DX Central Reporting Continued from page 33 There is much that has been written about satellite transmission of radio and television signals don t think that the use of satellites for rebroadcasting will re place shortwave transmissions not for a long time yet So Wayne think SWLing will in the next several years grow in popularity SW will probably change But I m not ready to write its obituary Of course there are quite a number of ELEMENTARY ELECTRONICS readers who enjoy BCB DXing listening to distant sta tions on the regular 540 1600 kHz AM radio band The CBC network on medium wave has provided me with many hours o
226. small double pole double throw speaker switch also under the dash Six is a hash suppressor which you may not need Some cars have em built in and other cars have alternators or generators whose output is clean enough not to leak into tape play back Photo below shows the player in place under the dash Be sure it s close enough that you can slide the cassettes in and remove them without leaning too far to the right and without taking your eyes off the road e Chances are that if you make cas sette recordings at home you ve given some thought to putting a cassette play er in your car or RV And if you re like most stereophiles there s a good chance you ve been turned off of the idea either by the total cost of a mobile cassette system or the possible theft of the equipment next time you take your car into town With a little common sense however you can not only enjoy a really good mobile cassette system at a budget price but you can also reduce the possibility of theft to zero Here s how it s done Generally a stereo cassette player needs at least two speakers and add on stereo speakers don t come cheap Also the speakers supplied in small almost cardboard enclosures don t offer much in the way of really good sound But if you have a radio already in the car there s a good chance you already have stereo speakers perhaps speakers front and rear with a front to rear fader If you don t have rear speakers
227. socket terminals 25 inch square The tool comes complete with a built in bit and sleeve for producing the standard modified style wrap CIRCLE 46 ON READER SERVICE COUPON A built in mechanical device prevents overwrapping Carefully designed and de veloped for the serious amateur the tool weighs only 11 ounces and runs on all standard or rechargeable C size batteries Pistol grip design of rugged ABS plastic positive indexing mechanism and quality construction assure reliable performance Price is 34 95 Batteries not included Available from local electronics suppliers or direct from O K Machine and Tool Corporation 3455 Conner Street Bronx N Y 10475 LI ELEMENTARY ELECTRONICS March April 1977 Hobbyist or professional there are probably a lot of circuits you build just for the fun of it And a lot you d ike to build but never get around to One reason is the cost of parts Parts you buy for one project but can tre use because you havent time to take them carefully apart Or because of heat and mechanical damage that occur when you do Now there s an easier way that can save you big money on parts and hours on every project as well Proto Board Solderless Breadboards Now assembling testing and modifying circuits iS aS easy as pushing in or pulling out a lead IC s LED s transistors resistors Capacitors virtually every kind of component connect and inter connect instantly
228. ssary When RNV CANTV does reappear on 5020 it will probably be much stronger than the Colombian Ecos del Atrato 49 Meters When those ionospheric conditions which make possible propa gation around 6 MHZ between North America and Europe collapse sometime before 0300 EST DXers have an ex cellent chance to log Colombia s net works All night stations include Emis ora Nueva Grenada at DIE rene fut gout x on o Kano Kuwunor LA EMISORA DE VENEZUELA Y SU CIRCUITO NACIONAL RUMBOS 6160 kHz the key station for Radio Cadena Nacional Colombia s most im portant network but not to be confused with the official government station Two more TODELAR affiliates are on this band R Continental Bogota on 6125 La Voz de Huila Neiva on 6150 There are also the Radio Super s at Medellin which recently moved to 6000 Bogota on 6065 and at Cali on 6120 kHz There is at least one all night Vene zuclan 49M broadacster It is a time station along the lines of WWV Obser vatario Cagigal on 6100 kHz Most 49M Venezuelan reception occurs when these stations sign on approximately be tween 0500 and 0600 EST Possibly the two most widely reported loggings during this period are R Turismo at Valera on 6180 and R Los Andes at Merida on 6010 kHz Unfortunately R Nacional does not sign on until 0700 but reception has been reported oc casionally in North America on 6170 Medium Wave BCB Dxrs have nu merous Colombian
229. ssons and experiments are described in full color Most liberal refund policy and cancella 4 HEAT SINK et 31 TRANSISTOR E7 LED DRIVER 33 ES E4 M 0 9 amp 9 S 9 4 23 J2 at IG CHIP E5 E8 EG Here s a detailed view of the Mod X module enlarged 1 3 times actual size to show terminal points at module edge Round black object in the middle is ihe actual IC chip find that the back is best because it makes mounting of the module very simple Be sure to check the soldered connections The solder balls should only be on their own connection points and not short circuited to any printed circuit wires More on Construction Note on the have their primary leads marked a and b and the secondary leads marked A and B The leads are not actually marked this way on the transformer itself but I have designated them this way for the project As shown on the schematic if you look down on the top of the transformers with primary to the schematic that transformers T1 and T2 left and secondary to the right the ALAAM SELECT ALARM DISPLAY SNOOZE M 1002 120 12200 VAC AB CORO 60 0 He BRIGHTNESS CONTROL E SLOW SET E FAST SET SLEEP DISPLAY SECUNDS DISPLAY amp isan 5 2 ims Sige 9 0 SLEEP Ve RADIO ALARM t3 oFF RADIO CHASSIS 2 WAKE MODE SELECT RADIO AND ALARM ES oo To i RADIO Diagram above is one supplied b
230. stic food container gets cut off near top to secure cover which seals speaker 45 Power Antique Radios the tolerance i e 5 Zeners are the most expensive while 20 are the cheapest If you want the closest regula tion buy 5 otherwise the output voltages may vary considerably Take the usual precautions when soldering use only rosin core solder and use a heat sink when soldering semiconductors As you can see from the photographs galavanized steel was used because it is easily obtainable and it doesn t show in the finished unit Pop rivets were used to hold the sheet metal toegther because the heads do not pro ject like machine screws When the power supply ts com pleted use your voltmeter to measure the output voltages before connecting to your radio A carefully built power supply will give you many hours of listening pleasure and will be well worth the time and money invested Figuring Component Values Here s how to figure the size of current limiting The secret of the Zener diode voltage regulating circuit is the current limiting resistor To figure the size of this resis tor you must know the voltage output of the bridge rectifier the load current drawn from the power supply and the voltage needed at the output of the supply Connect the power supply to the line and measure the voltage at point X with the balance of the circuit discon nected You choose the output voltage yourself Derive your chose
231. sting out all over In Citizens Band alone class D licenses grew from 1 to over 2 6 million in 1975 and the FCC projects about 15 million CB ers in the U S by 1979 That means a lot of service and maintenance jobs and NRI can train you at home to fill one of those openings NRIs Complete Communications Course covers all types of two way radio equipment including CB AM and FM special instruction so you can go on the air The complete course includes 48 lessons 9 special reference texts and 10 training kits Included are your own electronics Discovery Lab Antenna Applications Lab CMOS Frequency Counter and an Optical Transmission System You ll learn at home progressing at your own speed to your FCC license and into the communications field of your choice Transmission and Reception Television Broadcasting Microwave Systems Radar Principles Marine Electronics Mobile Communica tions and Aircraft Electronics The course will also qualify you for a First Class Radio Telephone Commercial FCC License or you get your tuition back Learn on your own 400 channel digitally synthesized VHF transceiver You will learn to service all types of communi cation equipment with the one unit that is designed mechanically and electronically to train meter fan handseon heinina Alco mandad you for CB Commercial and Amateur communi are 14 coaching units to make it easy to get cations a digitally
232. synthesized 400 channel VHF your commercial radio telephone FCC license transceiver and AC power supply This 2 meter enabling you to test install and service com unit gives you Power On training Then we munications equipment help you get your FCC Amateur License with NEW CB SPECIALIST COURSE NOW OFFERED NRI now offers a special course in CB Servicing You get 37 lessons 8 reference texts your own CB Transceiver AC power supply and multi Au choice of frequencies by a shortwave sta tion is a combination of technical plan ning and seat of the pants guesswork that can drive an SWL to distraction Often the fun times for DXers occur right after the seasonal frequency change dates when the international broadcasters begin their juggling for position in the shortwave bands If you want to keep tabs on these fre quency changes remember that the change over dates are the first Sundays in March May September and November News Briefs World Radio TV Handbook the so called SWL s Bible is expected to be available from about February 1 in its 1977 edition If there is one single refer ence and source book that listeners should have it is WRTH It contains frequency schedule and address listings for most sta tions in the world It is available for about 11 from many DX hobby clubs or from dealers such as Gilfer Associates Inc P O Box 239 Park Ridge NJ 07656 or Glen Mueller Billboard Publicati
233. t oscilloscopes The electron beam will follow the voltage amplitudes placed on the deflection plates If the waveforms are of the same frequency the Lissajous figure will re semble those obtained in measuring phase relation ships Frequency relationships can be determined by the number of loops or points that touch the top or bot tom and one of the sides of the pattern In the figures you have seen so far there is one point of tangency at the top and one at the side The frequency ratio is 1 1 the unknown has the same frequency as the standard In figure A one cycle of standard frequency appears on the horizontal plates at the same time that two cycles of the unknown are on the vertical plates There are two points loops of top tangency and one point of side tangency Frequency ratios should be expressed in terms of vertical unknown to horizontal standard The frequency ratio of figure A is 2 1 QUESTION Q10 What circuits must be bypassed in the horizontal channel to obtain a Lissajous figure on the screen ANSWER A10 The sync and sweep oscillator circuits must be by passed If a sawtooth wave and an external signal were fed to the horizontal deflection am plifier at the same time a Lissajous figure could not be developed The sweep oscillator would also be highly erratic Additional Samples of Lissajous Figures Both drawings provide a vertical horizontal un known standard ratio of 3 1 But they do not loo
234. t an angle of 45 degrees from horizon tal Thus the speaker can be placed on This exploded view shows the speaker driver and five associated parts all ready to go together just before being set around the neck of the cookie jar enclosure Metal ring next to the tep grille comes with it A four inch driver could also be used with the Masonite piece and the cover using a smaller center cutout in that case SPEAKER GRILLE METAL RING a low table or on the floor to provide good dispersion of the treble sound in the listening area An airtight seal be tween the driver and the enclosure is assured because we use the top section of a cylinder shaped plastic food con tainer and its cover The photographs and drawings show how the parts that make up the adaptor fit into each other The inside diameter MATERIALS LIST FOR COOKIE JAR SPEAKER SYSTEM quantities shown for stereo pair 2 Food storage container glass two gallon size used as enclosure Anchor Hocking or equiv 2 Freezette food containers no 117 soft plastic 6 in diameter 7 in high with COVer 2 Hardboard 6 in square or larger 4 in thick Masonite or equiv 2 Speaker grille automotive type 61 in diameter including metal retaining ring 2 Loudspeaker driver unit 5 in diameter Radio Shack 40 1292 40 1284 40 1909 40 1240 or equiv 8 Machine screws 1 in long round head no 8 32 with nuts and washers 8 No 6 shee
235. t is to buy it and try it The KIM 1 with manuals costs 245 the KIM 2 is 179 the KIM 3 is 289 and KIMath with doc umentation is about 50 These are not however the only add on modules avail able MOS Technology also has a text editor a program assembler to aid in writing programs and other things are in the works all the time For detailed specifications on the products write to MOS Technology 950E Rittenhouse Road Norristown Penna 19401 or circle number 73 on the Reader Service coupon In the next issue we will continue to keep abreast of the microcomputer world Stay tuned and remember to write to me with your interests ques tions and ideas E 57 a a Computer Readout the KIM Users Notes which are published roughly every two months The notes contain articles sent in by hobbyists on what they have been do ing programs they have written latest hardware and software available for the KIM 1 etc You can get on the mailing list by sending a 5 check to KIM 1 User s Notes care of Eric Rehnke Apt 207 7656 Broadview Road Parma Ohio 44134 KIM 1 As a Controller One of the advantages of a microprocessor as com pared to a calculator is the ease with which a microprocessor can be con nected interfaced using computer lingo to the outside world KIM 1 is particularly simple in this respect bc cause its input and output are perma nently associated with a few specific memory locations These s
236. t lines you have scribed on the masonite Since the speaker unit extends below the flange in this position it 1s a good idea to sup port them on two blocks of wood so that the speaker unit will hang between the blocks Accurate center marks can then be punched for drilling the holes for the four mounting screws Ihe large opening and screw holes to be made in the plastic cover are shown in the drawing To make a visible line on the soft plastic of the cover use a sharp pencil lead with a school compass ad justed to amp 15 16 inch radius A groove can be made in the plastic sur face to seribe the outline of the cutout Then trace the groove with a felt mark ing pen to make it more visible The 3 16 HOLE DRILL THROUGH COVER AND MASONITE SPACER AT SAME TIME 4 HOLES MASONITE SPACER TOP VIEW Completed speaker system looks like ordi nary cookie jar when viewed from side opening can now readily be cut with a sharp knife Template the mounting holes in the cover from the speaker frame or the Masonite piece Putting It Together Bolt the as sembly together with the machine screws and nuts using washers on the Continued on page 93 Drawing at left shows how to mask top of container prior to cutting with hacksaw sharp knife or scissors Drawing at lower left shows assembled system with speaker magnet assembly barely visible from side Cross section below and top view below show how to scribe cover fo
237. t metal self tapping screws 3A inch long similar wood screws are ac ceptable Speaker hookup wire gauge two conductor 24 COVER FROM PLASTIC CONTAINER 9 IN DRIVER MASONITE TOP SECTION CUT FROM PLASTIC CONTAINER ELEMENTARY ELECTRONICS March April 1977 of the food container at the cut off section is slightly less than the outside diameter of the glass around the open ing When installed it is stretched over the glass opening and pressed down all around to the body of the jar enclosure Note that the plastic screw on cover is placed between the back flange of the speaker unit and a masonite stiffening flange and serves as a gasket These parts are clamped together by four screws and nuts The glass jar and the plastic food container are available in supermarkets and variety drug stores The two gallon container has a 5 inch inside diameter opening The outside diameter is 6 inches Making the Parts Stick a length of masking tape around the food container an inch and one half from the open end to serve as a guide for sawing the plas tic body as indicated in the drawing Screw the cover on tightly before saw ing to add rigidity Hold the round body over an open vise or other double edged support Now rotate the body as you make the cut and scrap away the ragged edges with a file Scribe the straight and the circular lines on the smooth face of a piece of Pla
238. tandard wall socket through an AC adapter and the system is turned on Once on but not in use the equip ment can stay on for years with ex tremely little power drain and no dam age to the system This mode is similar to solid state television sets and radios which once they are plugged in are always on ready to start up instantly When the paraplegic wishes to dic tate he picks up the wand with his mouth and touches its magnetic end to a circle marked Record on the con trol unit Actually even coming close to this circle is sufficient A red light comes on to tell the users that the machine is now on the record mode The recording itself is voice activated VOX That is the person starts to template for Continued from page printed circuit board for B F Brain Use Radio Shack 276 1576 or 276 1560 kits making the speak and automatically the tape cas sette starts turning with a second light this one green indicating the motion When the person stops speaking there is a five second delay and the cassette stops automatically waiting for the next voice signal If the user wishes to rewind and listen to a particular section or to erase a portion of the tape he picks up the mouth wand and moves it to the differ ent circles on the control unit respon sible for these functions Standard cas settes can record for up to one hour per side so with one in the machine a paraplegic can record for t
239. ted Q5 Patterns placed on the screen to show phase rela tionship are called Q6 Why would you want to enlarge a waveform pres entation on an oscilloscope Q7 What is meant by the output stage in electronic equipment Q8 How can the phase relationship between two waveforms be measured using the oscilloscope Q9 When measuring the phase difference of two sig nals their frequencies must be ANSWERS A4 The trouble is in the sweep oscillator circuit This circuit has a good input but it has a faulty output A5 Patterns placed on the screen to show phase rela tionship are called Lissajous figures Two Waveforms Out of Phase 86 A6 The presentation is expanded for better accuracy when viewing a waveform A7 The output stage feeds the desired signal to the load of the equipment A8 AC signals are simultaneously applied to each set of deflection plates when comparing their phase A9 When measuring the phase difference of two sig nals their frequencies must be equal Analyzing a Lissajous Figure The drawing below shows what is called a Lissajous pattern for two sine waves Numbers have been as signed to corresponding voltage points on the two signals Extensions of these points are brought to the Lissajous Figures SINE WAVE ON HORIZONTAL e DEFLECTION PLATE SINE WAVES ON VERTICAL 4 DEFLECTION PLATE IN PHASE OR 360 P dh OUT OF PHASE 45 OR 315 on ary F OUT OF PHASE e
240. tely change from one to the other KIM 1 As an Educational Tool Fin ally with all the fun you can have with KIM 1 do not forget its educational value A few days of operating your own microprocessor will give you more understanding of its capabilities and possible applications than will reading dozens of books If you are an engineer or technician or are planning to study in those areas you will know that a good knowledge of microprocessors is indispensable Writing a few KIM 1 programs will teach you concepts of basic computer operation You will learn the computer instruction set and observe programs working by display ing appropriate memory locations Your final conclusion about Owning a micro processor may well be How did I ever get along without one before Memory Expansion It is not easy for ELEMENTARY ELECTRONICS March April MOS Technology s KIM 1 microcomputer is complete on one board except for the power supply Readout display is six 7 segment digits above the keyboard KIM 1 assembled sells for 245 people to expand their memories but with KIM 1 it is easy you just plug in the extra boards Suppose you have a super program like a big Star Trek game that requires more than the 1024 bytes that the basic KIM 1 can hold You can simply purchase a KIM 2 memory board which has 4096 loca tions or a KIM 3 which has 8192 loca tions or both and connect them to the basic computer Either of the boards can
241. ternational was the original pop music station in Europe many years ago There are other European out lets with pop music featured these days but RL goes on undaunted Listen for Eng lish on this frequency around 2300 9 655 Radio Thailand is heard on the west coast of North America with program ming in That but with an English identi fication at signoff just prior to 1430 GMT 15 084 A nice exotic sounding catch is Teheran s Voice of ran on this semi off beat frequency below the 19 meter band Listen about 1600 Credits Alan Merriman VA Robert A Yajko PA Gerald Arrington CA Sam Rowell WA Naitonal Radio Club Box 127 Boonton NJ 07005 American Short Wave Listening Club 16182 Ballad Lane Huntington Beach CA 92649 g ELEMENTARY ELECTRONICS March April 1977 4 TV Sets of The Future Continued from page 42 stereo sound Standing over 60 inch es high and 43 inches deep when in use Theatervision is comprised of an enclosed upfacing TV set Sony Model RM 204 for example covered by a projection lens assem bly a mirror and a tilted screen measuring 32 by 40 inches The lens fires TV program material at the mirror which in turn directs it onto the screen The mirror is in a draw er Which is pushed back into the main cabinet when the set is not in operation PM Systems Corp Cinema IV roman numeral Model CR priced at 1 995 is a large 35 by 25 by 49 inch self contained system fea
242. the popular KIM 1 computer on a board from MOS Technology In this column we delve deeper into KIM 1 s micro magic and have a guaranteed good time Cass and Dan Lewart avid KIM 1 users have given us lots of ideas on how to use this microcomputer that Pm sure you will find interesting First let s quickly review the basic KIM 1 It comes already assembled on a 9 x 10 inch printed circuit board that contains the MCS 6502 microprocessor chip over one thousand words or bytes of random access memory RAM a small keyboard for entering data or programs a six digit LED dis play and much more The first four dig its of the display show the address of a selected memory location in hexadeci mal code means 16 in Greek as ex plained last time where 0000 is the first location and O3FF is the last lo cation Remember that in hex sixteen numbers are represented with a single digit by using the notation 0 1 through 9 and A B through F Count em and you will find sixteen characters in this string So since O3FF is the last mem ory location we must have 4 x 16 x 16 or 024 memory cells available and indeed we do Going back to the six digit display the other two hex digits show the data contained in or being KIM 1 microcomputer can use a recorder as well as other input and or outputs put into the memory cells indicated by the four left most digits A data byte IS 8 bits Os and Is long all
243. the best to you regardless of the theo retically optimum placement suggested in the manual After all it s vour ears that do the listening Power In Sound Out These Heath kit column speakers are rated for a minimum input of 5 watts and a maxi spot the colors Actually it s as easy as wiring a lamp mum of 100 watts A 1 2 ampere pro tective fuse is provided in each wooter circuit and a l ampere fuse is provided for tweeter protection Normally an amplifier or receiver of 5 watts rated output ts all that s needed tor a comfortable sound level while 15 to 25 watts is required for a robust iloud sound In a typical living room of 15 x 20 feet about 20 watts per channel will produce a sound level more or less equal to that of a large orchestra in a concert hall The Heathkit AS 1344 Two Way Column Speaker System is available by mail order for 129 95 each Prices in local Heathkit stores are slightly high er For additional information circle No 31 on the Reader Service cou pon a For more information on the Heath AS 1344 Column Speaker kit circle No 31 on the Reader Service coupon 52 The bottom plate is almost ready to go in place just as soon as the sound absorbing material is dropped into the cabinet Note sponge like strips along bottom of the plate They keep an air tight seal as needed ELEMENTARY ELECTRONICS March April 1977 eee E Er CIRCLE 31 Most speaker systems rad
244. to room upstairs or Jf A CIRCLE 54 ON READER SERVICE COUPON downstairs to the basement garage or patio Just plug one into the nearest electrical outlet for instant audible con tact with the other stations The Realis tic SelectaCom FM Intercom priced at 119 95 is sold and serviced exclusively by Radio Shack Radio Shack stores and dealers are found in all 50 states and Canada Simple Security The trouble with many anti theft car devices is that the hookup is a lot of work The new compact Model 3001 Quick Connect Q C Auto and CB Se curity System requires only a 3 wire hook up to intermittently sound any car horn after illegal entry No horn relay is required The system is designed to pro tect CB radios scanners speakers tape deck stereo radios and your auto from being ripped off by thieves It is also for use in RVs sports cars and trucks It can be installed in less than 30 minutes The simple Q C alarm system is trig Continued on page 10 ELEMENTARY ELECTRONICS March April 1977 Ihe 40 channel Cobra 29XLR From the sleek brushed chrome face to the matte black housing its a beauty But its beauty is more than skin deep Because inside this CB has the guts to pack a powerful punch Iheilluminated 3 in 1 meter tells you exactly how much power you re pushing out And pulling in It also measures the system s efficiency with an SWR check In short this Cobra s meter lets you keep an eye on y
245. tration Board IFRB of the International Telecom munications Union in Geneva Switzerland Since 1960 the IFRB has attempted with some limited success to reduce the chaos of seasonal frequency changes by broadcasters The SWBC stations are sup posedly required to submit to the IFRB live months in advance of their actual use the shortwave frequencies the stations in tend to use IFRB then compiles these intended channel usages into a tentative schedule and recommends alterations in the plans when obvious problems appear to be pending Alternative frequencies are recommended in these cases The IFRB tries but it has no real muscle to act as a frequency traffic cop Thus while some countries scrupulously try to cooperate with the agency in providing frequency usage information real and planned others go their own merry way when it suits them And so it is not un common to find some of the major broad casters indicating intentions to use far more frequencies than they actually will use Other stations will jump from frequency to frequency looking for a competitive advantage with little consideration for the overall pattern of frequency use within given band So when all is said and done the actual GLOSSARY AM Amplitude modulation a transmis sion mode but sometimes used in a shorthand way to refer to the every day 540 to 1600 kilohertz Top 40 and Golden Oldie radio band DX Listening to distant radio s
246. ty Kansas Last year 1 was hearing some short wave stations regularly When winter came J couldn t hear them even if I sat on the frequency When spring came again there they were on the same frequencies again Do the changing seasons have some effect on the shortwaves Yes there is a seasonal change in short wave reception patterns And because of this shortwave stations alter their fre quency usage I ve tried to explain this earlier in this column Wayne I ve pub lished your question to show how reader comments and queries can provide me with information about the sort of material you d like to see in this column Wayne s second question is With Radio Canada International cutting back on some Of its services to SWLs and other stations giving up on shortwave altogether do you think SW will be popular in the future Will it live or die All I can do Wayne is give you my opinion No one can predict the long range future so I m not going to attempt to guess what the SW scene will be like in the year 2000 But it is my feeling that SWLing will continue and perhaps grow signifi cantly in the next ten years The SW scene will change surely Commercial and military communications use I m talking about fixed service point to pointers mari time and aeronautical transmissions will probably decrease This should effectively leave more shortwave space for the broadcasting stations Continued on page 94
247. u know that batteries don t come cheap And if the cost of the batteries doesn t get you their leakage will Leave the power switch on over night by accident and it s a good bet by next morning the hand held set wiil be dripping battery gook But there is a way to beat the prob lems of high battery upkeep and leak age and also to insure maximum RF output at the same time The answer Switch to nickel cadmium NiCad pen light batteries AA size Are they ex pensive Not any more A NiCad should cost about the price of two alkaline batteries or even less and the NiCad can be recharged hundreds pos o BANER Low cost project charges inexpensive nickel cadmium cells to keep you on the air for pennies an hour by Herb Friedman W2ZLF on the second or third recharge Hold on don t go running to the parts catalog to look up the price of NiCads you probably can t afford them at catalog prices What you need is a surplus dealer You sec today every one is in a hurry and most people can t wait the usual overnight period to re charge NiCads they demand a fast charge battery So hundreds of thou sands of the overnight or trickle charge NiCads were dumped on the surplus market and you can buy them for as little as a buck a piece no higher than 1 50 And you get a tremendous advantage with the trickle charge Ni Cads they hold their charge much longer than the fast charge type Charge em up stash the tran
248. u provide greater sensitivity to glass breakage and a more pleasing appearance One roll of tape will easily do any average size home Timer Delay An optional feature of the circuit i provision to add a capaci tor to produce a delay of several sec onds This feature will allow you to arm the alarm circuit before going out and then leave the house by a pro tected door It also permits you to enter the house through a protected door without sounding the alarm since you can shut the circuit off before the alarm sounds The basic circuit 1s shown first This is the complete alarm circuit con structed on a small printed circuit board Also shown is a layout of the foil pattern of the board viewed from the copper side We also show the com ponent layout as viewed from the top of the board Note that Q2 the power output transistor does not have any heat sink None is required since Q2 operates as a switch and not a class A amplifier When Q2 is conducting it IS in a saturated state This means that the collector to emitter voltage is about 0 3 volts Thus the total dissipation in Q2 is 0 3 volts times 3 amperes or 0 9 watts The average dissipation of Q2 is half of this since it is cut off for half of cach cycle when the alarm cir cuit is delivering power to the speaker Note the series of six connections located at one side of the board These are the required connections to the Power Supply Speaker Open circuit or Cl
249. umbers as MAN 4 s MAN All shapes 7100 Series Finest caps made As a gam momentaries etc E We don t wish to separate micas moldeds plastics Suppliers throw em in the 7 s MAN 3 s 11 burrels amp 8000 9000 ROMS RTL s pie we bought 10 barrels em shop pak for 100 s of wide asst voltages amp values ceramies discs etc Nifty barrel It s a li l gold mine no time to separate DTL s linears of all kinds from factory mixed values SWitching projects BARREL KIT 48 741 MINI DIP BARREL KIT 83 SGARREL KIT 81 BARREL KIT 776 BARREL KIT 75 15 for 1 S SUBMINI RESISTORS 1 WATT ZENERS 400MW ZENERS a LM 340T 200 for 3 100 for 1 98 100 for 1 98 Untested VOLT REG 1 98 Factory same as 400 mw s Factory out of biz Amazing singles tri 1 BC ory rejected them tor PC upright type color cod Never to see again offer 6 offer 6 8 10 12 to 16V to 0 6 Bot length of leads May include ed Ym watt Asst values 8 10 12 15V under Youtest Hermetically sealed al mixed 8 85 12 15 18 24 volts Came tn us in a barrel glass Double plug glass pak Double plug Power tab Cat 2L 2635 Cat No 2L 746 100 p good Cat No 2L 2741 Untested zat No 2L 2740 BARREL KIT 65 BARREL KIT 62 BARREL KIT 761 BARREL KIT 58 Cat No 2L 2726100 9 5 go BARREL KIT 37 1 AMP BULLETT No 2L2735 Cat No BARREL KIT 4
250. very sound in the home office and possibly the street and your on mike sounds will most likely overload the transceiver s mike input Use this mike properly and it s easy operating and easy listening on the receiving end Oh yes I shouldn t forget to mention that the 526T has a locking PTT switch You can either hold it down as long as you want to transmit or slide it slightly forward so it locks in the transmit position Summing Up But while sitting back and working no hands with voice no louder than a whisper sounds like the way to go if I had but one choice it would be for a barefoot unampli fied high performance noise cancelling microphone for when the QRM and QRN gets rough and the signal is com ing in slightly below the noise level it s the extra clean signal the one without distortion and extraneous noise pickup that gets the message through In short its not how loud the signal sounds that s important but rather how clean it sounds wall to wall distortion doesn t get your message through Keep in mind that while I ve shown the Shure versions of quality commu nications microphones other manufac turers make mikes of similar quality Just be certain you stick to the quality brands and you won t go wrong after all they have a reputation to protect Just remember there s nothing special about CB a mike that s quality material for any land mobile radio service is quality for CB E Kill T
251. video display generator key board interface serial and parallel inter faces for connection to external devices and an edge connector for memory ex pansion Optional extras include a power supply video monitor ASCII keyboard and case Other options are a floppy dik system high speed papertape reader PROM programmer and color graphics interface Because the Sol uses the 8080 memory can be expanded to 65 000 bytes The Sol is completely compatible with Imsai Altair and other S 100 bus computers Delivery is stock to 45 days after receipt of order For more informa tion please write to Processor Tech nology 6200 Hollis Street Emeryville CA 94608 Stylus Cleaner For clean sound you need a clean stylus on the phono So Audio Technica has come up with a stylus cleaner that combines a brush and fluid that are es pecially designed to keep the diamond tip free from dirt or waxy buildup The new Audio Technica stylus cleaner dis CIRCLE 50 ON READER SERVICE COUPON solves foreign materials and junk witnout harming stylus adhesives or record sur faces Used regularly the new AT607 cleaner prolongs disc life It is ideal for tone arms operating at low tracking force For application info write to Audio Technica 33 Shiawassee Avenue Fair lawn OH 44313 Solderless Breadboards Continental Specialties CSC has two new solderless breadboarding sockets Designated Experimentor 300 and Ex perimentor 600 the new one pi
252. w and then the FCC does impale some of these channel jumpers as th FCC calls them and when they do they make an example ELEMENTARY ELECTRONICS March April stations operate home service relays to reach the more remote areas of their country The most widely reported is R Barquisimeto s on 9510 kHz Continued from page 44 l about 50 per cent for safety margin Caution Be careful not to turn the power supply on except when there is a load across each output Should the supply be operated unloaded there is a chance the output voltage at either or both outputs might rise sufficiently to overload one or all of the zeners with too much current and destroy one or more of them Trouble Finding Parts You may have trouble finding a few of the parts shown in the parts list If you do you can substitute electrolytic capacitors by using any capacitance larger than that specified and any working voltage higher than the ones indicated Happy listening of the caught stations by coming down rather hard on them But this has failed to stem the tide of the many stations which seem to crowd onto these chan nels in daily increasing numbers Achievement Many serious operators would like to work toward various operators awards this is also a little known aspect of CBing Actually it s not illegal if you stay on frequency and DX only to 150 miles It is possible to earn about 100 different awards these days and
253. when the band is not crowded and all signals are weak However if you are working a local with plenty of signal turn down the RF gain control if your set has one and it will reduce the background noise and weak signals I know of two remote chain stores that stay in touch with beam antennas and reduced gain Only their signals get through except for the moments when some mobile rides be ELEMENTARY ELECTRONICS March April 1977 ASK HANK HE KNOWS 590 ger some microPs on the covers Continued from page 27 feet of radiating or receiving conductor Incidentally our unit forms a helical resonator which is impedance matched to a 50 ohm coaxial transmission line This results in much greater efficiency and a greater received signal The antenna may be tuned io any frequency from about 3 4 MHz to over 60 MHz Ellen J Arnow Chief Engineer Telethon Data Corp P O Box 84 Kings Park NY 11754 The world is getting smaller Our an tenna project called Boinger used a toy Slinky coil to form a retractable vertical antenna The Slinky Dipole antenna is another cat it s horizontally polarized for the 80 40 and 20 meter shortwave bands Why not get all the facts by writing to E J Arnow at the address given above From a Poet In late 1978 when CB has met its fate We will remember the spree that started in 73 And our radios we will give to the state But in late 1985 when microPs buz like bees in a hive We will re
254. wo 9v tran sistor batteries offers features comparable to many costlier models A comprehensive in struction booklet is included No 1689EK JusT 99 Ppd LOW COST HIGH QUALITY INFRA RED EYE Binocular Style 329 95 Standard Only 299 95 Patent Pending wit No 1689EK Do It Yourself Kit 61069EK 37 50 ppd Low Cost Starter Unit 71809 EK 59 95 ppd A must for Infra red crime detection surveil lance security system alignment I R detec tion laser checking night time wildlife Study any work requiring I R detection and conversion to the visible spectrum Self contained scope 11 x 14 x 3 includes I R light source for up to 90 sight at night 6032 I R converter tube 5 38 telephoto lens adjustable triplet eyepiece an adapter for use with your car s Cigarette lighter mare Bright 1 6X image Binocular style gives super bright 2 5X Focuses from 10 to infinity runs on 6 or 12v DC Not for sale to Cal residents other than authorized by U S Armed Forces law enforcement agencies or solely for scientific research and education purposes STANDARD STYLE STOCK NO 1683EK ONLY 299 95 Ppd BINOCULAR STYLE STOCK NO 1685EK JUST 329 95 Ppd COMPLETE AND MAIL COUPON NOW GIANT EREE Electronic sound conditioner simulates 4 kinds of soothing sounds of ocean surf amp rain white sound helps mask un wanted noise Medical tests p
255. wo parts supply houses you should contact and obtain their parts cata logs International Unlimited P O Box 3036 Monterey CA 93940 and New Tone Electronics P O Box 1738 Bloom field NJ 07003 Just 15 More I have a portable CB rig that runs on D cells Can add one extra D cell to pep up the signal output D M Birmingham AL No First of all this addition of a D cell would be tantamount to modifying your CB transmitter which would invali date your rigs FCC type acceptance Further the extra voltage may upset the circuits resulting in damage off frequency operation or poor reception Need more power go ham Lend a Hand Boys Several of our readers need help that you may be able to give If you don t want to part with the original copy of a diagram or manual write to the person in need and tell him the cost for Xeroxing A F M Engle of 1001 Victory Dr Minden LA 71055 needs a manual schematic dia gram and dial cord diagram for the Halli crafter SX 28 A Fd like to restore a Globe Sidebander D S B 100 that s missing all the tubes and transformer If you can help write to Donald Walker D amp M CB Sales P O Box 394 Marrero LA 70073 A Hf you have the schematic diagram for the Atwater Kent Model 20 receiver send a copy to James P Dillman 721 Nichols St Clearfield PA 16830 A Gary Nelson would like a schematic diagram and other info on the Ameco AC transmitter Write to Gary at
256. x Flectronics in the News COVER 40 CHANNELS NOW CX 1000 3 75 dB GAIN CITIZEN S BAND BASE ANTENNA Designed to withstand nature s abuse CX 1000 is an 18 high package of dynamite performance for AM or sideband This omnidirectional base antenna has a precision tuned coaxial stub system for perfect match and low ohmic losses Made of heavy wall bright finish seamless aluminum tubing and stainless steel fasteners TRUNK BUSTER FIBERGLASS MOBILE SUPERVACUUM CHAMBER IBM scientists have designed and built a chamber large enough to hold several experiments in a vacuum So nearly perfect that it is beyond the capability of present day instruments to measure By extrapolation from what E M 2 Our 48 Top loaded or tunable tip ET EN antenna with solid one piece no hole MA trunk lip mount The mount has foam RS J N protective pad and spring loaded aN E cable contact Complete high per a E fi i M TO formance systems preassembled with 18 cable and connector CM 403 Trunk mt with 48 whip CM 404 Trunk mt with 48 tunable whip 7 p L 1 3 m in Cushcraft products are stocked by dealers throughout the world C cushcratt CORPORATION P O BOX 4680 MANCHESTER N H 03108 i Dr William A Thompson right and Mr CIRCLE 22 ON READER SERVICE COUPON Stephen F Hanrahan of IBM have designed and bu
257. y and di vide millions of them at a terrific speed Some people think that because the speed of the KIM 1 is about 500 000 operations per second it can help in balancing the checking account faster Well that view is not quite correct be cause if the calculations are of the or dinary kind and there is not much data to crunch you can just buy a pocket calculator On the other hand if you have a large amount of data you might need a teletypewriter a card reader a high speed printer and a keypunching machine These are all expensive items far beyond the scope of a simple hob byist installation Well then what good is your KIM 1 The answer is that it is super as a controller a universal game machine and as an educational tool In these applications your KIM 1 will real ly shine These three application areas are discussed in more detail in the fol lowing paragraphs First I must give you a little advice Join a microcom puter Users Club You will be able to exchange your ideas with those of other KIM 1 owners and you will learn a lot in the process Further you do not have to be a computer owner to join a club An excellent way to become fa miliar with KIM I is by subscribing to 95 Speaker System This Heath speaker kit is a confidence builder Page size diagrams guide the assembler every step of the way eliminating goofs that would be made usually by novices Also checking is simple to do White area seen in holes
258. y will tend to overheat and maybe self destruct Excessive heating in a lead acid battery causes sulfation plate buckling and electrolyte boil off The net result will be an interior short in one of the cells If the battery survives its overall capacity to deliver its rated ampere hours will be greatly reduced Please Ease Off Fellows Hank you didn t answer my last two letters Everything okay with you D N Waverly TN Yes except no one listens to me I can not answer letters 1 can only read them and answer only those which are typical of many received in my column So please don t send stamped self addressed enve lopes or postcards There are not enough hours in the day to answer all my readers letters personally Pumps RF Also My 1974 Vega has an electric fuel pump that makes about an 9 racket in my CB set The pump is located inside the fuel tank so I assume it uses an oscillator in place of an interrupted contact to drive it I have tried all the usual types of filters and bypass cures but to no avail I also contacted General Motors Service and got nothing there except a large telephone bill Can you help R L Lowell IN The trouble may be your antenna coax line Check it very carefully The fuel pump lines pass through the trunk As a quick check turn on your direction lights If you hear the clicking your antenna line is defective Otherwise you may have to take the CB power line directl
259. y National Semiconductor showing optional fea tures you can add if you want more functions just by adding switches to circuit Transformer is special made for clock manufacturers It s easy to replace this as the author has with two small Radio Shack transformers Transistor at bottom of dia gram with base connected to terminal E1 is used as switch to turn external radio On or Off Diodes to its left are rectifiers for radio s power supply ELEMENTARY ELECTRONICS March April 1977 a and A leads will be towards your hair and the b and B leads will be toward your chin Follow the schematic when connecting these leads Also do not forget to use a heat sink when soldering to transistor Ql Finally im portant watch out for tricky S4 Most DPDT switches including the ones on the parts list are backwards When the toggle is up the bottom contacts are engaged So watch how you do the wiring and labeling of the switch or you will be confused later on Testing Your clock should work well the first time you try it so before you plug if tn go through the thing every body hates Check and double check your wiring If the display fails to light you have probably forgotten to connect pin 3 on the clock module to pin 4 The voltage AC between E6 and E8 on the module should be about 15 volts The DC voltage reading between ES positive and E7 negative should be about 5 volts If these voltages are not correct
260. y for mobile CB appli cation The VS 19 is a twin element design incorporating two high quality speakers The unit is engineered for high voice definition Self contained clips that enable quick mount CIRCLE 42 ON READER SERVICE COUPON ing on the visor are supplied with the VS 19 The VS 19 complete with cable and mini plug retails for about 15 For further in formation on the VS 19 and other Superex products write to Marketing Director Su perex Electronics Corp 151 Ludlow St Yonkers NY 10705 3 Maec Hello out there in Radioland The AWA Antique Wireless Assn con ference took place the first weekend in October 1976 but this is my first op portunity to tell you about it There was a continuous Flea Market both days an old radio equipment auction semi nars on vacuum tubes talks on restor ing old radios historical presentations on Crosley and the end of RCA s tube production But most of all I enjoyed meeting collectors who read my column in ELEMENTARY ELECTRONICS Many collectors and their wives came up to tell me that I was responsible for them being there Many said they had read Antique Radio Corner and immedi ately subscribed to this magazine so as to not miss an issue Some had been collecting radios for years without be ing aware that there were other col lectors living nearby or that there were clubs for collectors or even knew that the AWA existed It certainly made me feel
261. y s posi tive terminal for safety s sake Then disconnect the lead that goes from the alternator to the starter solenoid and connect it to one terminal of the feed thru filter Attach a cable to handle the hook up from the feed thru filter s remaining terminal to the terminal on the solenoid at the alternator hot cable s original connection The best kind of cable to use is the approved auto cable It should handle up to 40 amps or more and it is available from automotive supply stores Connections should be kept short and without cable flop or unnecessary loops The Sprague QXI series of feed thru filters comes in 20 40 60 100 and 200 ampere ratings 40 amps is more than adequate for the average car The feed thru filter should knock out the whine and most of the snap crackle and pops youll hear on your mobile CB tape player and in dash radio If your car doesn t need a feed thru filter today it may need one to morrow when you switch to a new CB model That s right sometimes the CB rig installation causes whine problems The filter is always the best remedy CB whine can usually be eliminated by installing a simple filter such as this one ELEMENTARY ELECTRONICS March April 1977 i Rathis by Kathi Martin KGK3916 sel Powermikes What They Can Do For You Just about any good idea can be ruined by overapplication Take power mikes as an example It all started back in the d
262. y settings because of the different speeds at which the beam travels across the screen For this reason it may be necessary to adjust the Intensity and Focus controls occasionally while taking readings QUESTION Q1 What should you do before you turn on the oscil loscope ANSWER A1 You should carefully study the manual that comes with the scope before turning the scope on 83 Servicemaster will find the signal generators channel selector calibrated 22 24 25 23 26 2 etc In short every needed CB test fre quency is available at a flip of the switch In the event the FCC expands the Citizens Band beyond 40 channels at a later date a simple modification can expand the 2040 s output to 100 channels The right side of the generator pro vides a fully metered RF output cali brated directly in microvolts and dB The RF output appears at a standard coaxial jack The attenuator provides full scale output from 1 to 100 000 uV in 10 dB steps And an RF level control permits the output to be adjusted to any value from 1 to 100 000 uV A standard EIA noise pulse generator for testing noise limiters is activated when you simply pull outward the RF level control knob The noise pulse can be added to a modulated or unmodu lated signal Since the pulse closely ap proximates the waveshape of typical electrical noises picked up by the CB receiver it is a convenient and accurate way to judge the effectiveness of the ANL and
263. y to the battery instead of the accessory power line Can anyone else suggest a remedy Dial Troubles How do I know the frequency calibra tions on my SWL receiver dial are ac curate H N Macon GA I can tell you for sure it s not accurate I checked my receiver with an RF signal generator and an electronic frequency counter Pumping a known signal into my rig proved the dial was a little off I did some fine tuning adjustments in the RF circuit but some error still remained So I made up a calibration chart for each band At each half inch across the eight inch dial I knew how many cycles to add or subtract to each dial reading In gen eral the error possibility increases as the band frequency increases Call For Heip Hank can you tell me if it s natural for a transmitter within 1000 ft of my base to splatter 2 to 3 channels each side of his transmit frequency on AM and wipe out my incoming signals on all AM channels with a loud hiss when he s on SSB This is my first radio experience and 1 have a tendency to feel I have done something wrong J T Michigan City IN Can t see how it can be your fault un less you damaged your rig somehow I sug gest you call a few good buddies to moni tor the station in question and see what they report If they agree with your re ception report approach the station in volved and offer friendly advice Maybe Tovarish Maybe Do 1 have to be a citizen to get a C
264. you ELEMENTARY ELECTRONICS March April 1977 Nan ASTROPLANE CB base give yo patented construction features are so exceptional they are covered by U S Patent 3587109 4 46 db gain over isotropic provides a stronger signal in and out To make use of the better signal the Astroplane radiates the signal from higher up than other CB antennas and at a better angle According to Dr Alva Todd of the Midwest College of Engineering it possesses an unusually low angle of maximum radiation This low angle of radiation means that your power is radiated at the horizon and not up into the clouds for greater efficiency You ll also get long lasting trouble free performance be cause it is compact in design without long drooping radials without coils to burn or short out and high power capacity for lightning and static dis sipation 36 95 Suggested Retail Length 12 Ft Dia 30 in Free 24 page color catalog Avanti makes a complete line of high performance base and mobile CB antennas from 11 95 to 373 95 Nan RESEARCH AND DEVELOPMENT INC 340 Stewart Avenue Addison IL 60101 The unique lt Creators of the famous MOONRAKER CIRCLE 6 ON READER SERVICE COUPON burglar alarm catalog over 900 systems detectors controls sounders tools locks supplies TO PROTECT HOMES BUSINESSES INDUSTRY Huge selection of hard to find security

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