Contents
Contents
1. Contents 29 1 Fixed Stations 29 2 Mobile Installations 29 1 1 Selecting a Location 29 2 1 Installation 29 1 2 Station Ground 29 2 2 Coax 29 1 3 Station Power 29 2 3 Wiring 29 1 4 Station Layout 29 2 4 Amplifiers 29 1 5 Interconnecting Your Equipment 29 2 5 Interference Issues 29 1 6 Documenting Your Station 29 2 6 Operating 29 1 7 Interfacing High Voltage Equipment to 29 3 Portable Installations Solid State ACOESSONES 29 3 1 Portable AC Power Sources 29 3 2 Portable Antennas Chapter 29 Assembling a Station Although many hams never try to build a major project such as a transmitter receiver or amplifier they do have to assemble the vari ous components into a working station There are many benefits to be derived from assembling a safe comfortable easy to operate collection of radio gear whether the shack is at home in the car or in a field This chapter will detail some of the how tos of setting up a station for fixed mobile and portable operation Such topics as station location finding adequate power sources station layout and cable routing are covered It includes contributions from Wally Blackburn AA8DX a section on mobile installations from Alan Applegate KOBG and information on gasoline generators from Kirk Kleinschmidt NTQZ 29 1 Fixed Stations Regardless of the type of installation you are attempting good planning greatly increases your chances of success Take the time to t2. 29 10 Chapter 29 29 2 2 Coax Cable lengths in mobile installations sel dom exceed 15 ft so coax losses are not a major factor except for 70 cm and above Good quality RG 58A or RG 8X size coax is more than adequate for HF and VHF While there is nothing wrong with using RG 8 size coax 0 405 inch it is stiffer and has a larger bending radius making it harder to work with in most mobile applications There are some caveats when selecting coax Avoiding solid center conductors such as standard RG 58 It has a propensity to kink is prone to vibration and can be dif ficult to solder properly Both RG 58A and RG 8X use foam dielectric and care is need ed when soldering PL 259 connectors es pecially when reducers are being used The Component Data and References chapter illustrates the correct installation procedure When applying heat use a large wattage iron with enough latent heat to flow the solder quickly Soldering guns shouldn t be used for this reason 29 2 3 Wiring Proper wiring is an essential part of any mobile installation Consider the following points when selecting materials and planning the cable routing e Wire needs to be correctly sized and fused and of stranded construction e All cables need to be protected from abra sion heat and chemicals e Wiring needs to be neat and tidy to avoid interaction with passengers and mechanical devices This means excess wiring should be s
3. A portable station located in the bed of the pickup truck completes the installation The second method of mounting portable beams described by WA7LY Iis shown in Fig 29 29 This support is intended for use with small or medium sized VHF and UHF arrays The tripod is available from any dealer selling television antennas tripods of this type are usually mounted on the roof of a house Open the tripod to its full size and drive a pipe into the ground at each leg Use a hose clamp or small U bolt to anchor each leg to its pipe Fig 29 28 The portable tower mount ing system by WA7LYI At A a truck is parked on the homemade base plate to weigh it down At B the antennas mast and rotator are mounted before the tower is pushed up Do not attempt to climb a temporary tower installation The rotator mount is made from a 6 inch long section of 1 5 inch diameter pipe weld ed to the center of an X made from two 2 ft long pieces of concrete reinforcing rod rebar The rotator clamps onto the pipe and the whole assembly is placed in the center of the tripod Large rocks placed on the rebar hold the rotator in place and the antennas are mounted on a 10 or 15 ft mast section This system is easy to make and set up TIPS FOR PORTABLE ANTENNAS Any of the antennas described in the An tennas chapter or available from commer cial manufacturers may be used for portable operation Generally though big or heavy
4. into service to support wire antennas Droop ing dipoles are often chosen over horizontal dipoles because they require only one sup port An aluminum extension ladder makes an effective antenna support as shown in Fig 29 25 In this installation a mast rota Assembling a Station 29 15 HBKO5_ 19 31 120 Plan View Mast Bolted to Ladder Rope or Wire Guys 3 Pairs Guy Anchor Pipe Driven into Ground Extension Ladder 80 of Mast Height Hole in Ground to Keep Base from Walking Fig 29 25 An aluminum extension ladder makes a simple but sturdy portable antenna support Attach the antenna and feed lines to the top ladder section while it is nested and lying on the ground Push the ladder vertical attach the bottom guys and extend the ladder Attach the top guys Do not attempt to climb this type of antenna support tor and beam are attached to the top of the second ladder section with the ladder near the ground The ladder is then pushed vertical and the lower set of guy wires attached to the guy anchors When the first set of guy wires is secured the ladder may be extended and the top guy wires attached to the anchors Do not attempt to climb a guyed ladder Telescoping fiberglass poles Figs 29 26 and 29 27 are popular for supporting wire verticals inverted Vs and small VHF UHF antennas These poles can extend up to 40 ft in length yet retract to 4 to 8 feet for easy transport They typical
5. AX photo Connectors F BNC SMA N UHF SMA UHF PHONO Fig 29 14 Each type of RF connector is specially made to carry RF signals and preserve the shielding of coaxial cable Adapters are available to connect one style of connector to another N AX photo Phono plugs and jacks sometimes called RCA connectors since they were first used on RCA brand equipment are used for audio video and other low level RF signals They are also widely used for control signals The most common microphone connector on mobile and base station equipment is an 8 pin round connector On older transceivers you may see 4 pin round connectors used for microphones RJ 45 modular connectors see the section on telephone connectors below are often used in mobile and smaller radios RF Connectors Feed lines used for radio signals require special connectors for use at RF frequencies The connectors must have approximately the same characteristic impedance as the feed line they are attached to or some of the RF signal will be reflected by the connector Inex pensive audio and control connectors cannot meet that requirement nor can they handle the high power levels often encountered in RF equipment Occasionally phono connectors are used for HF receiving and low power transmitting equipment By far the most common connector for RF in amateur equipment is the UHF family shown in Fig 29 14 The UHF designator has nothing to do with fr
6. Fig 29 6 Example station layout as seen from the front A and the top B The equipment is spaced far enough apart that air circulates on all sides of each cabinet Assembling a Station 29 3 shelf like that shown in Fig 29 5 can improve equipment layout in many situations Dimen sions of the shelf can be adjusted to fit the size of your operating table When you have acquired the operating table and shelving for your station the next task is arranging the equipment in a conve nient orderly manner The first step is to provide power outlets and a good ground as described in a previous section Be conserva tive in estimating the number of power outlets for your installation radio equipment has a habit of multiplying with time so plan for the future at the outset Fig 29 6 illustrates a sample station layout The rear of the operating table is spaced about 1 ft from the wall to allow easy access to the rear of the equipment This installation incorporates two separate operating posi tions one for HF and one for VHF When the operator is seated at the HF operating posi tion the keyer and transceiver controls are within easy reach The keyer keyer paddle and transceiver are the most often adjusted pieces of equipment in the station The speak er is positioned right in front of the operator for the best possible reception Accessory equipment not often adjusted including the amplifier antenna switch and rotator control
7. Mobile amplifiers for VHF UHF operation are not as popular as they once were because most mobile transceivers have adequate out put power about 50 W Boosting this to 150 300 W or more should be done with caution Mobile VHF UHF antennas for high power gt 100 W are rare so check antenna ratings carefully Those that are available need to be permanently mounted and preferably on the roof to avoid inadvertent contact 29 12 Chapter 29 V a Aisy With any high power mobile installation pay careful attention to RF safety More in formation on RF exposure is in the Safety chapter 29 2 5 Interference Issues In a mobile installation radio frequency interference falls under two basic categories egress interference from the vehicle to your amateur station and ingress from your ama teur gear to the vehicle Most hams are famil iar with ignition interference as it is the most common form of egress Auto sound system feedback is a common form of ingress Both types of interference have unique solutions but they have at least one in com mon and that s bonding Bonding refers to strapping the various bolted on pieces to the frame or chassis of the vehicle For example the exhaust system is isolated from the struc ture of the vehicle and acts like an antenna for the RFI generated by the ignition system It should be strapped in at least three places Figs 22 23 shows an example of bonding More on these t
8. a 120 V ac power source The 120 V ac is then converted to the proper ac or dc levels required for the station equipment RF power amplifiers typically require 240 V ac for best operation Power supply theory is covered in the Power Supplies chapter and safety issues and station wiring are covered in the Safety chapter If your station is located in a room with electrical outlets you re in luck If your station is located in the basement an attic or another area without a convenient 120 V source you will have to run a line to your operating position Fig 29 3 Scott KA9FOX operated this well laid out station W9UP during a recent contest Photo courtesy NOBSH SURGE PROTECTION Typically the ac power lines provide an adequate well regulated source of electrical power for most uses At the same time these lines are fraught with frequent power surges that while harmless to most household equip ment may cause damage to more sensitive devices such as computers or test equipment A common method of protecting these de vices is through the use of surge protectors More information on these and lightning protection is in the Safety chapter 29 1 4 Station Layout Station layout is largely a matter of per sonal taste and needs It will depend mostly on the amount of space available the equipment involved and the types of operating to be done With these factors in mind some basic design considerations apply t
9. an operating Antenna Storage HE Shelves Linear for Amp Glue and Screw All Adjoining Surfaces Front and Rear Apron Braces Glue and Screw All Adjoining Surfaces Drill and Countersink Top for Flat Head Wood Screws Aprons position An example is shown in Fig 29 4 ARRANGING THE EQUIPMENT No matter how large your operating table some vertical stacking of equipment may be SWR Rotator Power Control Meter Box VHF Amp Power Supply Solid State VHF Amplifier Paperwork Transceiver Speaker and Power Supply HF Transceiver Computer Keyboard on Pullout Shelf Transceiver Computer Completed Unit Fig 29 5 A simple but strong equipment shelf can be built from readily available materials Use 3 4 inch plywood along with glue and screws for the joints for adequate strength HBKO5_ 19 05 necessary to allow you to reach everything from your chair Stacking pieces of equip ment directly on top of one another is not a good idea because most amateur equip ment needs airflow around it for cooling A Monitor Printer Ground Bus Paperwork Storage HBKO5_19 06 Equipment Shelf Writing Area Computer AN p SD Alternative R Keyboard Location
10. at 64 Hz As loads in crease frequency and voltage decrease Un der full load output values may fall as low as 105 V at 56 Hz Normal operating conditions are somewhere in between Some hams have tried inserting uninter ruptible power supplies UPSs between the generator and their sensitive gear These devices are often used to maintain steady clean ac power for computers and telecom munication equipment As the mains voltage moves up and down the UPS s Automatic Voltage Regulation AVR system bucks or boosts accordingly The unit s internal batter ies provide power to the loads if the ac mains or your generator go down In practice however most UPSs can t handle the variation in frequency and voltage of a generator powered system When fed by a standard generator most UPSs constantly switch in and out of battery power mode or don t ever switch back to ac power When the UPS battery goes flat the unit shuts off Not every UPS and every generator lock horns like this but an inverter generator is a better solution DC Output Some generators have 12 V dc outputs for charging batteries These range from 2 A trickle chargers to 100 A powerhouses Typi cal outputs run about 10 to 15 A As with the ac outputs be sure to test the de outputs for voltage stability under load if possible and ripple Car batteries aren t too fussy about a little ripple in the charging circuit but your radio might not like it a
11. example avoid temporary mounting schemes such as hook and loop fasteners magnets elastic cords and wedged in blocks of wood If you re not into building a specific mount for your vehicle there are a plethora of no holes needed mounts available from Amateur Radio dealers Some mounts are Table 29 1 for case 2 is shown in Fig 29 15B This cir cuit is simply the mirror image of that in Fig 29 15A with respect to circuit polarity Here a P channel device is used to actuate the nega tive line from a positive only control switch Cases 3 and 4 require the addition of an inverter as shown in Fig 29 16 The inverter provides the logic reversal needed to drive the gate of the MOSFET high activating the control line when the control switch shorts the input to ground Almost any power MOSFET can be used in the level converters provided the voltage and current ratings are sufficient to handle the signal levels to be switched A wide variety of suitable devices is available from most large mail order supply houses even designed for a specific transceiver make and model Table 29 1 lists some suppliers The main points to keep in mind when choosing a mounting location are safety which should always be considered first convenience and lack of distraction The radio mounting location must avoid SRS airbag deployment zones virtually eliminating the top of the dash in most modern vehicles as well as vehicle controls Microph
12. ground connections 3 Ground loops These matters are treated in precise scien tific research equipment and certain industrial instruments by attention to certain rules The ground conductor should be at least as large as the largest conductor in the primary power 29 2 Chapter 29 circuit Ground conductors should provide a solid connection to both ground and to the equipment being grounded Liberal use of lock washers and star washers is highly rec ommended A loose ground connection is a tremendous source of noise particularly in a sensitive receiving system Ground loops should be avoided at all costs A short discussion here of what a ground loop is and how to avoid them may lead you down the proper path A ground loop is formed when more than one ground currentis flowing in a single conductor This commonly occurs when grounds are daisy chained series linked The correct way to ground equipment is to bring all ground conductors out radially from a common point to either a good driven earth ground or a cold water system If one or more earth grounds are used they should be bonded back to the service entrance panel Details appear in the Safety chapter Ground noise can affect transmitted and received signals With the low audio levels required to drive amateur transmitters and the ever increasing sensitivity of receivers correct grounding is critical 29 1 3 Station Power Amateur Radio stations generally require
13. stored in a heavy rotating flywheel for example to bring or keep the shaft speed up to par The opposite happens if the generator is spinning too fast In addition to mechanical and vacuum speed regulating systems generators that are a step up in sophistication additionally have electronic automatic voltage regulation AVR systems that use special windings in the generator core and a microprocessor or circuit to monitor and control them to help frequency hash which makes reception tire some Using adapters to interface with ve hicle stereo systems isn t productive for the same reason Selecting one too large and mounting becomes a safety issue For best results use at least a 4 inch speak er Rather than mount it out in the open mount it under the seat out of the way This also attenuates the high frequencies enhances the lows and increases intelligibility keep things steady near 120 V and 60 Hz AVR systems can respond to short term load changes much more quickly than mechani cal or vacuum governors alone A decade ago AVR generators were the cream of the crop Today they re mostly used in medium to large units that can t practically employ inverters to maintain the best level of output regulation You ll find them in higher quality 5 to 15 kW home backup systems and in many recreational vehicles Isolate Source and Load Basic inexpensive generators are intend ed to power lights saws drills ac
14. W D1 15 V 1 W Zener diode 1N4744 or U1 CD4049 CMOS inverting hex buffer equiv one section used unused sections not Q3 IRF620 shown pins 5 7 9 11 and 14 tied to Q4 IRF220 see text ground sucha way as to cause it to fail What is needed is another form of level converter MOSFET LEVEL CONVERTERS While relays can often be rigged to inter face the equipment their noise slow speed and external power requirement make them an unattractive solution in some cases An al ternative is to use power MOSFETs Capable of handling substantial voltages and currents power MOSFETs have become common de sign items This has made them inexpensive and readily available Nearly all control signals use a common ground as one side of the control line This leads to one of four basic level conversion sce narios when equipment is interconnected 1 A positive line must be actuated by a negative only control switch 2 A negative line must be actuated by a positive only control switch 3 A positive line must be actuated by a positive only control switch 4 A negative line must be actuated by a negative only control switch In cases 3 and 4 the polarity is not the problem These situations become important when the control switching device is inca pable of handling the required open circuit voltage or closed circuit current Case 1 can be handled by the circuit in Fig 29 15A This circuit is ideal for inter f
15. acing keyers designed for grid block keying to positive CW key lines A circuit suitable 29 2 Mobile Installations Solid state electronics and miniaturization have allowed mobile operators to equip their vehicles with stations rivaling base station installations Indeed it is possible to operate from 160 meters through 70 cm with one compact transceiver Adding versatility most designed for mobile transceivers are set up so that the main body of the radio can be safely tucked under a seat with the operating head conveniently placed for ease of use as shown in Fig 29 17 It is not uncommon for power levels to exceed 100 W on HF and 50 75 W on VHF With proper antenna selection and place ment see the Antennas chapter mobile stations can work the world just like their base station counterparts The only real dif ference between them is that you re trying to drive at the same time you are operating and safe operating requires attention to the details For some of us living in antenna restricted areas mobile operating may offer the best solution for getting on the air For others it is an enjoyable alternative to home station operation No matter which category you re in you can enjoy success if you plan your installation with safety and convenience in mind 29 2 1 Installation Installing Amateur Radio equipment in modern vehicles can be quite challenging yet rewarding if a few basic rules are followed For
16. antennas should be passed over in favor of smaller arrays The couple of decibels of gaina 5 element 20 m beam may have over a 3 ele ment version is insignificant compared to the mechanical considerations Stick with arrays of reasonable size that are easily assembled Wire antennas should be cut to size and tuned prior to their use in the field Be careful when coiling these antennas for transport or you may end up with a tangled mess when you need an antenna in a hurry The coaxial cable should be attached to the center insula tor with a connector for speed in assembly Use RG 58 for the low bands and RG 8X for higher band antennas Although these cables exhibit higher loss than standard RG 8 they are far more compact and weigh much less for a given length Beam antennas should be assembled and tested before taking them afield Break the beam into as few pieces as necessary for trans portation and mark each joint for speed in reas sembly Hex nuts can be replaced with wing nuts to reduce the number of tools necessary Fig 29 29 The portable mast and tripod by WA7LYI At A the tripod is clamped to stakes driven into the ground The rotator is attached to a homemade pipe mount At B rocks piled on the rotator must keep the rotator from twisting and add weight to stabilize the mast At C a 10 ft mast is inserted into the tripod rotator base assembly Four 432 MHz Quagis are mounted at the top Asse
17. back of this Yaesu FT 950 transceiver shows some of the many types of connectors encountered in the amateur station Note that this variety is found on a single piece of equipment Assembling a Station 29 5 of damage from incorrect mating Plugs are connectors installed on the end of cables and jacks are installed on equipment Adapters make connections between two dif ferent styles of connector such as between two different families of RF connectors Other adapters join connectors of the same family such as double male double female and gender changers Splitters divide a signal between two connectors While the number of different types of connectors is mind boggling many manu facturers of amateur equipment use a few standard types If you are involved in any group activities such as public service or emergency preparedness work check to see what kinds of connectors others in the group use and standardize connectors wher ever possible Assume connectors are not waterproof unless you specifically buy one clearly marked for outdoor use and assemble it correctly Power Connectors Amateur Radio equipment uses a variety of power connectors Some examples are shown in Fig 29 11 Most low power amateur equip ment uses coaxial power connectors These are the same type found on consumer elec tronic equipment that is supplied by a wall transformer or wall wart style of power supply Transceivers and other equipment tha
18. box is located on the shelf above the trans ceiver The SWR power meter and clock of ten consulted but rarely touched are located where the operator can view them without head movement All HF related equipment can be reached without moving the chair This layout assumes that the operator is right handed The keyer paddle is operated with the right hand and the keyer speed and transceiver controls are operated with the left hand This setup allows the operator to write or send with the right hand without having to cross hands to adjust the controls If the operator is left handed some repositioning of equipment is necessary but the idea is the same For best results during CW operation the paddle should be weighted to keep it from walking across the table It should be oriented such that the operator s entire arm from wrist to elbow rests on the tabletop to prevent fatigue Some operators prefer to place the station transceiver on the shelf to leave the table top clear for writing This arrangement leads to fatigue from having an unsupported arm in the air most of the time If you rest your elbows on the tabletop they will quickly become sore If you rarely operate for pro longed periods however you may not be inconvenienced by having the transceiver on the shelf The real secret to having a clear table top for logging and so on is to make the operating table deep enough that your entire arm from elbow to wrist rests o
19. e Sh it easy to do station maintenance as well as comfortable to use through 29 3 all found the right spot for them Weigh the trade offs and decide which features you can do without and which are necessary for your style of opera tion If possible pick an area large enough for future expansion 29 1 2 Station Ground Grounding is an important factor in overall station safety as detailed in the Safety chap ter An effective ground system is necessary for every amateur station The mission of the ground system is twofold First it reduces the possibility of electrical shock if something in a piece of equipment should fail and the chassis or cabinet becomes hot If connected to a properly grounded outlet a three wire electrical system grounds the chassis Much amateur equipment still uses the ungrounded two wire system however A ground system to prevent shock hazards is generally referred to as dc ground The second job the ground system must perform is to provide a low impedance path to ground for any stray RF current inside the station Stray RF can cause equipment to mal function and contributes to RFI problems This low impedance pathis usually called RF ground In most stations dc ground and RF ground are provided by the same system GROUND NOISE Noise in ground systems can affect our sensitive radio equipment It is usually related to one of three problems 1 Insufficient ground conductor size 2 Loose
20. e if tested with a standard ac outlet polarity tester Some users religiously drive copper ground rods into the ground or connect the metal frames of their generators to suitable existing grounds while others vigorously op pose this method and let their generators float with respect to earth ground arguing that if the generator isn t connected to the earth you can t complete the path to earth ground with your body should you encounter a bare wire powered by the generator no path no shock Some user manuals insist on the ground con nection while others don t You can follow your unit s user manual check your local electric code choose a grounding method based on personal prefer ence or expert advice or do further research Either method may offer better protection depending on exact circumstances Regardless of the grounding method you choose a few electrical safety rules remain the same Your extension cords must have intact waterproof insulation three prongs and three wires and must be sized according to loads and cable runs Use 14 to 16 gauge three wire extension cords for low wattage runs of 100 feet or less For high wattage loads use heavier 12 gauge three wire cords designed for air compressors air conditioners or RV service feeds If you use long extension cords to power heavy loads you may damage your generator or your radio gear When it comes to power cords think big Try to posi tion exte
21. e wiring rules The use of a multiple outlet power distribution panel such as a RigRunner www westmountain radio com is also recommended They re b Fig 29 21 Wiring attached to a fuse block interior body panels convenient and offer a second level of pro tection WIRE SIZE The Component Data and References chapter lists the current handling capabili ties of various gauges or wire and cable The correct wiring size is one that provides a low voltage drop less than 0 5 V under full load Don t go by maximum current current car rying capacity Here s the formula for calculating the cable assembly voltage drop V4 Va Rw x2 x0 001 2 k xI where Rw resistance value Q per 1000 ft from the Component Data and References chapter l overall length of the cable assembly including connectors in feet k nominal resistive value for one fuse and its holder Note Most power cables have two fuses If yours doesn t use 1 k in the formula If you don t know the fuse and holder resistance use a conservative value of 0 002 Q I peak current draw in amperes for a SSB transceiver or steady state for an FM radio For example the peak current draw for a 100 W transceiver is about 22 A and a typical power cable length is 10 ft Using the resistive values for 1000 feet of 10 AWG wire 0 9987 Q and a conservative value for the fuse resistances 0 002 Q each the calculated dr
22. echniques is available at www k0bg com bonding html Other RFI egress problems are related to fuel pumps HVAC and engine cooling fans ABS sensors data distribution sys tems and control system CPUs These are best cured at the source by liberal use of snap on ferrite cores on the wiring harness es of the offending devices Snap on cores come is a variety of sizes and formulations called mixes The best all around ferrite core material for mobile RFI issues is Mix 31 Suitable cores are available from most Amateur Radio dealers Unknown surplus units typically offer little HF attenuation and should be avoided See the Electromagnetic Compatibility and Component Data and References chapters for more information on ferrite cores Alternator whine is another form of RFI egress It is typically caused by an incor rectly mounted antenna resulting in a ground loop rather than a defective alternator diode Fig 29 23 Bonding vehicles parts in this case the trunk lid to the main body can help reduce interference Brute force filters only mask the problem and increase I R losses Additional informa tion on proper antenna mounting is in the Antennas chapter RFI ingress to the various on board elec tronic devices is less common The major causes are unchecked RF flowing on the control wires and common mode currents flowing on the coax cable of remotely tuned HF antennas Again this points out the need to properly mou
23. efore in the amateur station The con nector styles follow those found on computer equipment D type connectors are used for RS 232 COM ports and parallel LPT port in terfaces A typical D type connector has a model number of DB followed the number of connections and a P or S depending on whether the connector uses pins or sockets For example the DB 9P and DB 9S are used for PC COM1 and COM2 serial ports USB connectors are becoming more popular in amateur equipment as the com puter industry moves to eliminate the bulkier and slower RS 232 interface A number of manufacturers make devices for interfacing transceivers and station equipment through computer USB ports Null modem adapters or cables are used to connect data circuits when direct connections between the data interfaces would connect outputs to outputs and inputs to inputs Pinouts for various computer connectors are shown in the Component Data and Ref erences chapter More information about in terfacing may be found in the Digital Basics chapter and several practical interface proj ects are shown in the Station Accessories and Digital Communications chapters Telephone and Computer Network Connectors Modular connectors are used for telephone Assembling a Station 29 7 and computer network connections Connec tor part numbers begin with RJ The con nectors are crimped on to multiconductor cables with special tools The RJ11 connect
24. equency A PL 259 is the plug that goes on the end of feed lines and the SO 239 is the jack mounted on equipment A barrel PL 258 is a double female adapter that allows two feed lines to be con nected together UHF connectors are typically used up to 150 MHz and can handle legal limit transmitter power at HF UHF connectors have several drawbacks including lack of weatherproofing poor per formance above the 2 meter band and limited power handling at higher frequencies The Type N series of RF connectors addresses all of those needs Type N connectors are somewhat more expensive than UHF con nectors but they require less soldering and perform better in outdoor use since they are moisture resistant Type N connectors can be used to 10 GHz For low power uses BNC connectors are often used BNC connectors are the standard for laboratory equipment as well and they are often used for dc and audio connections BNC connectors are common on handheld radios for antenna connections The newest handheld transceivers often use small screw on SMA type connectors for their antennas though The type of connector used for a specific job depends on the size of the cable the fre quency of operation and the power levels involved More information on RF connec tors may be found in the Component Data and References chapter Data Connectors Digital datais exchanged between comput ers and pieces of radio equipment more than ever b
25. ge where it should not be Wire and cables should have good quality insulation that is rated high enough to prevent shock hazards Interconnections should be neatly bundled and labeled Wire ties masking tape or paper labels with string work well See Fig 29 9 Whatever method you use proper label ing makes disconnecting and reconnecting equipment much easier Fig 29 10 illustrates the number of potential interconnections in a modern full featured transceiver WIRE AND CABLE The type of wire or cable to use depends on the job at hand The wire must be of suf Fig 29 9 Labels on the cables make it much easier to rearrange things in the station Labeling ideas include masking tape cardboard labels attached with string and labels attached to fasteners found on plastic bags such as bread bags DC IN ee YK e aN NPUT DC A v 22A 10 vpRon ROT wh E s UE LINEAR TUNER RITY PKT PTT REC REM SPKR KEY ficient size to carry the necessary current Use the tables in the Component Data and References chapter to find this information Never use underrated wire it will be a fire hazard Be sure to check the insulation too For high voltage applications the insulation must be rated at least a bit higher than the intended voltage A good rule of thumb is to use a rating at least twice what is needed Use good quality coaxial cable of sufficient size for connecting transmitters transceivers an
26. hink the project all the way through consider alter natives and make rough measurements and sketches during your planning and along the way You will save headaches and time by avoiding shortcuts What might seem to save time now may come back to haunt you with extra work when you could be enjoying your shack One of the first considerations should be to determine what type of operating you intend to do While you do not want to strictly limit your options later you need to consider what you want to do how much you have to spend and what room you have to work with There is a big difference between a casual operating position and a big gun contest station for example 29 1 1 Selecting a Location Selecting the right location for your station is the first and perhaps the most important step in assembling a safe comfortable convenient station The exact location will depend on the type of home you have and how much space can be devoted to your station Fortunate amateurs will have a spare room to devote to housing the station some may even have a separate building for their exclusive use Most must make do with a spot in the cellar or attic or a corner of the living room is pressed into service Examine the possibilities from several angles A station should be comfortable odds are good that you ll be spending a lot of time there over the years Some unfinished basements are damp and drafty not an ideal environment for several
27. hortened and or bundled with appropriate wire ties Fig 29 20 shows a typical vehicle wiring trough Power cables should be connected directly to the battery following manufacturers rec ommendations with the requisite positive and negative lead fuses located close by Fig 29 21 shows a fuse block Accessory cigarette lighter sockets and power taps shouldn t be used except for very low cur rent loads lt 5 A and then only with care It pays to remember that a vehicle fire is both costly and dangerous More information may be found at www fordemc com docs download Mobile_Radio_Guide pdf and service gm com techlineinfo radio html Proper wiring also minimizes losses and helps prevent ground loops Modern solid state transceivers will operate effectively down to 12 0 V dc engine off If the volt age drops below 11 6 V under load most transceivers will shut down or operate in correctly The vehicle chassis should not be used for ground returns doing so can create a ground loop Firewall access can be easy in some ve hicles and nearly impossible in others Using factory wiring grommets should be avoided unless they re not being used In some cases the only alternative is to drill your own hole If you have any questions or concerns have your local mobile sound shop or two way radio dealer install the wiring for you Power for ancillary equipment wattme ters remotely tuned antennas and so on should follow the sam
28. hours of leisurely hamming Attics have their drawbacks too they can be stifling during warmer months If possible locate your station away from the heavy traf fic areas of your home Operation of your station should not interfere with family life A night of chasing DX on 80 m may be ex citing to you but the other members of your household may not share your enthusiasm Keep in mind that you must connect your station to the outside world The location you choose should be convenient to a good power source and an adequate ground If you use a computer and modem you may need ac cess to a telephone jack There should be a fairly direct route to the outside for running antenna feed lines rotator control cables and the like Although most homes will not have an ideal space meeting all requirements the right location for you will be obvi ous after you scout around The amateurs whose stations are depicted in Figs 29 1 Fig 29 1 Randy K5ZD has arranged his equipment for efficient contest operation The computer keyboard and monitor occupy center stage flanked by two transceivers and amplifiers and various accessories and control switches Photo courtesy Andrew Thompson Assembling a Station 29 1 9 A Fig 29 2 Ward N AX has had great suc cess with this simple low power QRP station tucked away in the corner of a room All equipment fits on a computer cart and small rolling cabinet that mak
29. ice as an increase in background level Add in a little traffic noise and by the end of your transmis sion you re in full shout mode One solution is to use a headset and the transceiver s built in monitor function Doing so gives you direct feedback not a time delayed echo and your brain won t get confused Note that headset use is not legal in some jurisdictions and never legal if both ears are covered Even more convenient are cordless Bluetooth headsets Amateur manufacturers are adopting the technology and at least one aftermarket unit is available The best part is they leave your hands free to drive Overcoming vehicle ambient noise levels often requires the use of an external speaker and all too often it is an afterthought Se lecting a speaker too small accentuates high 29 3 Portable Installations Many amateurs experience the joys of por table operation once each year in the annual emergency exercise known as Field Day Set ting up an effective portable station requires organization planning and some experience For example some knowledge of propagation is essential to picking the right band or bands for the intended communications link s Por table operation is difficult enough without dragging along excess equipment and anten nas that will never be used Some problems encountered in portable operation that are not normally experienced in fixed station operation include finding an appropriate power sou
30. justed frequently sits on the tabletop while equipment requiring infrequent adjustment is perched on a shelf All equipment is positioned so the opera tor does not have to move the chair to reach anything at the operating position ERGONOMICS Ergonomics is a term that loosely means fitting the work to the person If tools and equipment are designed around what people can accommodate the results will be much more satisfactory For example in the 1930s research was done in telephone equipment manufacturing plants because use of long nosed pliers for wiring switchboards required considerable force at the end of the hand s range of motion A simple tool redesign re solved this issue Considerable attention has been focused on ergonomics in recent years because we have come to realize that long periods of time spent in unnatural positions can lead to repetitive motion injuries Much of this atten tion has been focused on people whose job tasks have required them to operate comput ers and other office equipment While most Amateur Radio operators do not devote as much time to their hobby as they might in a full time job it does make sense to consider comfort and flexibility when choosing furni ture and arranging it in the shack or workshop Adjustable height chairs are available with air cylinders to serve as a shock absorber Footrests might come in handy if the chair is so high that your feet cannot support your lower leg
31. ly weigh less than 20 pounds and some are much lighter 29 16 Chapter 29 Figs 29 28 and 29 29 illustrate two meth ods for mounting portable antennas described by Terry Wilkinson WA7LYI Although the antennas shown are used for VHF work the same principles can be applied to small HF beams as well In Fig 29 28A a 3 ft section of Rohn 25 tower is welded to a pair of large hinges which in turn are welded to a steel plate measuring approximately 18 x 30 inches One of the rear wheels of a pickup truck is parked on the plate ensuring that it will not move In Fig 29 28B quad array anten nas for 144 and 222 MHz are mounted on a Rohn 25 top section complete with rotator Fig 29 27 Close up of a telescoping mast Sections slide together and are secured by twisting a locking mechanism Fig 29 26 Telescoping fiberglass poles can be used to support a variety of wire antennas or small VHF UHF Yagis This one is 40 feet long yet collapses to 8 feet for storage and feed lines The tower is then pushed up into place using the hinges and guy ropes anchored to heavy duty stakes driven into the ground complete the installation This method of portable tower installation offers an exceptionally easy to erect yet sturdy antenna support Towers installed in this manner may be 30 or 40 ft high the limiting factor is the number of pushers and rope pullers needed to get into the air
32. many models are stated on the box but try to test them yourself or talk to some one who owns the model you re interested in before buying Environmental conditions distance to the generator and the unit s phys ical orientation can affect perceived noise levels Generators housed in special sound damp ened compartments in large boats and RVs can be much quieter than typical outside models However they are expensive and heavy use more fuel than compact models and most don t have regulation specs com parable to inverter models Regulation For hams voltage and frequency regula tion are the biggies AVR units with electronic Table 29 2 Specifications of the Inverter Generators Shown in Fig 29 24 Make and Model Output W Run Time h Noise Range Engine Type Weight Notes Surge Cont Full 25 Load dBA 21 feet Pounds McCulloch FDD210MO N A 1800 4 N A 60 70 105 6 cc 3 HP 65 shipping a b Honda EU2000i 2000 1600 4 15 53 59 100 cc OHC 46 a b c Yamaha EF2400iS 2400 2000 N A 8 6 53 58 171 cc OHV 70 a b c Subaru Robin R1700i N A 1650 N A 8 5 53 59 2 4 HP OHV 46 a b c a has 12 V dc output b has smart throttle for better fuel economy c has low oil alert shutdown 29 14 Chapter 29 output regulation at aminimum and inverter generators are highly desirable and should be used exclusively if only for peace of mind Unloaded standard generators can put out as much as 160 V ac
33. mbling a Station 29 17
34. modern units are smaller and lighter than their predecessors Models suitable for hamming typi cally weigh between 25 and 125 pounds specifications Engines and Fuel Low end generators are typically powered by low tolerance side valve engines of the type found in discount store lawnmowers They re noisy need frequent servicing and often die quickly Better models have over head valve OHV or overhead cam OHC engines pressure lubrication low oil shut down cast iron cylinder sleeves oil filters electronic ignition systems and even fuel injection These features may be overkill for occasional use but desirable for more consis tent power needs Run Time Smaller generators usually have smaller gas tanks but that doesn t necessarily mean they need more frequent refueling Some small generators are significantly more ef ficient than their larger counterparts and may run for half a day while powering small loads As with output power run times for many units are somewhat exaggerated and are usu ally spec d for 50 loads If you re running closer to max capacity your run times may be seriously degraded The opposite is also true Typical generators run from three to nine hours on a full tank of gas at a 50 load Noise Except for ham friendly inverter units which are eerily quiet thanks to their high tech sound dampening designs standard generators are almost always too loud Noise levels for
35. motors electric frying pans and other devices that can reliably be run on cruddy power If you want the highest margin of safety when powering computers transceivers and other sensitive electronics a portable inverter gen erator is the best way to go Some popu lar examples are shown in Fig 29 24 and their key specifications are shown in Table 29 2 Available in outputs ranging from 1 to 5 kW these generators use one or more of the mechanical regulation systems mentioned previously but their ultimate benefit comes from the use of a built in ac dc ac inverter system that produces beautiful if not per fect 60 Hz sine waves at 120 V ac with a 1 to 2 tolerance even under varying load conditions Instead of using two windings in the generator core an inverter generator uses 24 or more windings to produce a high frequency ac waveform of up to 20 kHz A solid state inverter module converts the high frequency ac to smooth dc which is in turn converted to clean tightly regulated 120 V ac power And that s not all Most inverter generators are compact lightweight and quiet GENERATOR CONSIDERATIONS In addition to capacity and output regula tion other factors such as engine type noise level fuel options fuel capacity run time size weight cost or connector type may fac Assembling a Station 29 13 tor in your decision Consider additional uses for your new generator beyond Field Day or other portable o
36. n the table with the front panels of the equipment at your fingertips This leaves plenty of room 29 4 Chapter 29 Fig 29 7 It was back to basics for Elias K4IX during a recent Field Day Fig 29 8 Richard WB5DGR uses a homebrew 1 5 kW amplifier to seek EME contacts from this nicely laid out station for paperwork even with a microphone and keyer paddle on the table The VHF operating position in this station is similar to the HF position The amplifier and power supply are located on the shelf The station triband beam and VHF beam are on the same tower so the rotator control box is located where it can be seen and reached from both operating positions This opera tor is active on packet radio on a local VHF repeater so the computer printer terminal node controller and modem are all clustered within easy reach of the VHF transceiver This sample layout is intended to give you ideas for designing your own station Study the photos of station layouts presented here in other chapters of this Handbook and in QST Visit the shacks of amateur friends to view their ideas Station layout is always changing as you acquire new gear dispose of old gear change operating habits and in terests or become active on different bands Configure the station to suit your interests and keep thinking of ways to refine the layout Figs 29 7 and 29 8 show station arrangements tailored for specific purposes Equipment that is ad
37. nsion cords so they won t be tripped over or run over by vehicles And don t run electrical cords through standing water or over wet sloppy terrainch During portable operations try to let all operators know when the generator will be shut down for refueling so radio and computer gear can be shut down in a civilized manner Keep the loads disconnected at the genera tor until the generator has been refueled and restarted 29 3 2 Portable Antennas An effective antenna system is essential to all types of operation Effective portable antennas however are more difficult to de vise than their fixed station counterparts A portable antenna must be light compact and easy to assemble It is also important to remember that the portable antenna may be erected at a variety of sites not all of which will offer ready made supports Strive for the best antenna system possible because operations in the field are often restricted to low power by power supply and equipment considerations Some antennas suitable for portable operation are described in the An tennas chapter ANTENNA SUPPORTS While some amateurs have access to a truck or trailer with a portable tower most are limited to what nature supplies along with simple push up masts Select a portable site that is as high and clear as possible Eleva tion is especially important if your operation involves VHF Trees buildings flagpoles telephone poles and the like can be pressed
38. nt mobile antennas For more information on RFI issues see the Electromagnetic Compatibility chapter The ARRL RFI Handbook and the ARRL Technical Information Service www arrl org tis 29 2 6 Operating The most important consideration while operating mobile in motion is safety Driv er distraction is a familiar cause of vehicle crashes While Amateur Radio use is far less distracting than cell phones there are times when driving requires all of our attention When bad weather excessive traffic or a construction zone require extra care play it safe and hang up the microphone and turn off the radio In addition to properly installing gear a few operating hints can make your journey less distracting One of those is familiariza tion with your transceiver s menu functions and its microphone keys if so equipped Even then complicated programming or adjustments are not something to do while underway Logging mobile contacts has always been difficult Compact digital voice recorders have made that function easy and inexpen sive Units with up to 24 hours of recording time are under 50 For maximum intelligibility at the other end avoid excessive speech processing and too much microphone gainch Don t shout into the mic It s human nature to increase your oral volume level when excited or when the background level increases In the closed cabin of a vehicle your brain interprets the reflected sound from your own vo
39. o all stations THE OPERATING TABLE The operating table may be an office or computer desk a kitchen table or a custom made bench What you use will depend on space materials at hand and cost The two most important considerations are height and size of the top Most commercial desks are about 29 inches above the floor This is a comfortable height for most adults Heights much lower or higher than this may cause an awkward operating position The dimensions of the top are an important consideration A deep 36 inches or more top will allow plenty of room for equip ment interconnections along the back equip ment about midway and room for writing toward the front The length of the top will depend on the amount of equipment being used An office or computer desk makes a good operating table These are often about 36 inches deep and 60 inches wide Drawers can be used for storage of logbooks head Fig 29 4 The basement makes a good location if it is dry A ready to assemble computer desk makes an ideal operating table at a reasonable price This setup belongs to WK8H Photo courtesy AA8DX phones writing materials and so on Desks specifically designed for computer use often have built in shelves that can be used for equipment stacking Desks of this type are available ready to assemble at most discount and home improvement stores The low price and adaptable design of these desks make them an attractive option for
40. one and power cabling should be placed out of the way and properly secured The transceiver s controls should be convenient to use and to view See Fig 29 18 for examples Mounting radios inside unvented center consoles and overhead bins should also be avoided Modern mobile transceivers de signed for remote mounting allow the main body to be located under a seat in the trunk or in another out of the way place Fig 29 19 but be sure there is plenty of ventilation Fig 29 17 In this mobile installation the transceiver control head is mounted in the center console next to a box with switches for adjusting the antenna Mobile Mount Sources Gamber Johnson www gamberjohnson com Havis Shields www havis com Jotto Desk www jottodesk com PanaVise Products www panavise com RAM Mounting Systems www ram mount com Assembling a Station 29 9 A Fig 29 18 At A the transceiver control head is attached to one of many available mounts designed for this purpose Mounts are typically highly adjustable allowing the control head or radio to be positioned close to the operator An antenna controller is mounted below the microphone At B HF and VHF transceiver control heads and the microphone are all mounted to the dashboard within easy reach Fig 29 19 The main body of the radio may be mounted in the vehicle s trunk or other out of the way spot Allow for plenty of ventilation
41. op will be 0 527 V It s important to reiterate that the wire size should be selected for minimum voltage drop not maximum power handling capability The voltage drop is often referred to as I R loss Fig 29 20 Most vehicles have wiring troughs hidden behind Time Sec 1 100 HBK0407 Current Amps Fig 29 22 Chart of opening delay versus current for five common sizes of Maxi fuses the plastic body high current fuses common in vehicles Based on a chart from Littelfuse Corp Assembling a Station 29 11 the current in amperes squared times the resistance and should be held to a mini mum whenever possible In cabling exces sive PR losses can cause the wire to overheat with predictable results The insulation material of wire used in mobile installations should have a tempera ture rating of at least 90 C and preferably 105 C It should be protected with split loom covering whenever possible especially under hood wiring Selecting the correct size fuse is also im portant The average current draw for any given fuse should not exceed 60 of its rating Thus the correct fuse rating for a 22 A load is 30 A That same 30 A fuse will handle a 40 A load for abo
42. or is used for single and double line telephone system connection with 4 or 6 contacts The RJ10 is a 4 contact connector for telephone handset connections Ethernet computer network connections are made using RJ45 connectors with 8 contacts 29 1 6 Documenting Your Station An often neglected but very important part of putting together your station is properly documenting your work Ideally you should diagram your entire station from the ac power lines to the antenna on paper and keep the in formation in a special notebook with sections for the various facets of your installation Having the station well documented is an invaluable aid when tracking down a problem or planning a modification Rather than hav ing to search your memory for information on what you did a long time ago you have the facts on hand Besides recording the interconnections and hardware around your station you should also keep track of the performance of your equipment Each time you install a new an tenna measure the SWR at different points in the band and make a table or plot a curve Later if you suspect a problem you ll be able to look in your records and compare your SWR with the original performance In your shack you can measure the power output from your transmitter s and amplifier s on each band These measure ments will be helpful if you later suspect you have a problem If you have access to a signal generator you can measure recei
43. ou refuel at night use a light source that isn t powered by the generator and can t ig nite the gasoline Testing Before starting or restarting the engine disconnect all electrical loads Starting the unit while loads are connected may not dam age the generator but your solid state devices may not be so lucky After the engine has warmed up and stabilized test the output voltage and frequency if possible before connecting loads Because unloaded values may differ from loaded values be sure to test your genera tor under load using high wattage quartz lights or an electric heater as appropriate Notice that when you turn on a hefty load your generator will hunt a bit as the engine stabilizes Measure ac voltage and frequency again to see what the power conditions will be like under load See your unit s user manual or contact the manufacturer if adjustments are required Safety Grounds and Field Operation Before we can connect real electrical loads in a Field Day situation we need to choose a grounding method a real controversy among campers RVers and home power en thusiasts To complicate matters most generators have ac generator grounds that are connected to their metal frames but some units do not bond the ac neutral wires to the ac ground wires as in typical house wiring Although they will probably safely power your ham station all day long units with unbonded neutrals may appear defectiv
44. peration Capacity Your generator must be able to safely pow er all of the devices that will be attached to it Simply add up the power requirements of all the devices add a reasonable safety margin 25 to 30 and choose a suitably powerful generator that meets your other requirements Some devices especially electric motors take a lot more power to start up than they dotokeeprunning A motor that takes 1000 W to run may take 2000 to 3000 W to start Many items don t require ex tra start up power but be sure to plan accord ingly Always plan to have more capacity than you require or conversely plan to use less gear than you have capacity for Running on the ragged edge is bad for your generator and BE em your gear Some generators are somewhat j f ta pa Ch overrated probably for marketing purposes es e ok Give yourself a margin of safety and don t E rely on built in circuit breakers to save your gear during overloads When operating at or beyond capacity a generator s frequency and voltage can vary widely before the current breaker trips Fig 29 24 Modern inverter generators from McCullough Honda Yamaha and Subaru Robin Size and Weight A z Size and weight vary accord See Table ing to power output low A of power units are lightweight and physically small while beefier models are larger weigh more and probably last longer Watt for watt however most
45. rce and erecting an ef fective antenna The equipment used should be as compact and lightweight as possible A good portable setup is simple Although you may bring gobs of gear to Field Day and set it up the day before during a real emergency speed is of the essence The less equipment to set up the faster it will be operational 29 3 1 Portable AC Power Sources There are three popular sources of ac power for use in the field batteries dc to ac invert ers and generators Batteries and inverters are covered in detail in the Power Supplies chapter This section will focus on gasoline generators Essentially a generator is a motor that s operating backward When you apply elec tricity to a motor it turns the motor s shaft allowing it to do useful work If you need more rotational power add more electricity or wind a bigger motor Take the same motor and physically rotate its shaft and it generates electricity across the same terminals used to supply power when using the motor as a motor Turn the shaft faster and the voltage and frequency increase Turn it slower and they decrease To some degree all motors are generators and all generators are motors The differences are in the details and in the optimization for specific functions A motor that is optimized for generating electricity is an alternator just like the one in your car The most basic generators use a small gas engine to power an ac alterna
46. rry Coaxial Power gt i t Jacks Banana Plugs Binding Posts Fig 29 11 These are the most common connectors used on amateur equipment to make power connections Courtesy of Wiley Publishing Ham Radio for Dummies or Two Way Radios and Scanners for Dummies Quick Disconnect L c Ring amp Fork Step 2 Insert wire into terminal Step 3 Crimp the terminal on the wire Fig 29 12 Power connectors often use terminals that are crimped onto the end of wires with special crimping tools Courtesy of Wiley Publishing Ham Radio for Dummies or Two Way Radios and Scanners for Dummies Audio and Control Connectors Consumer audio equipment and Amateur Radio equipment share many of the same connectors for the same uses Phone plugs and jacks are used for mono and stereo audio circuits These connectors shown in Fig 29 13 come in inch inch miniature and sub miniature varieties The contact at the end of the plug is called the tip and the connector at the base of the plug is the sleeve If there is a third contact between the tip and sleeve itis the ring these are stereo phone connectors 4 s Microphone Connectors Adaptors Miniature Phone Data Connectors Fig 29 13 Audio and data signals are carried by a variety of different connectors Individual cable conductors are either crimped or soldered to the connector contacts N
47. t all Miscellaneous Other considerations include outlets 120 V 240 V and dc output circuit breakers stan dard or ground fault interrupter type fuel level gauges handles one or two favorite brands warranties starters pull or electric wheels handles or whatever you require SETUP SAFETY AND TESTING Before starting the engine read the user manual Carefully follow the instructions regarding engine oil throttle and choke set tings if any Be sure you understand how the unit operates and how to use the receptacles circuit breakers and connectors Make sure the area is clean dry and un obstructed Generators should always be set up outdoors Do not operate gas powered engines in closed spaces inside passenger vans inside covered pickup beds etc Ifrainis a possibility set up an appropriate canopy or other outdoor protective structure Operating generators and electrical devices in the rain or snow can be dangerous Keep the generator and any attached cords dry Exhaust systems can get hot enough to ignite certain materials Keep the unit several feet away from buildings and keep the gas can and other flammable stuff at a safe dis tance Don t touch hot engines or mufflers When refueling shut down the generator and let things cool off for a few minutes Don t smoke and don t spill gasoline onto hotengine parts A flash fire or explosion may result Keep a small fire extinguisher nearby If y
48. t requires high current in excess of a few amperes often use Molex connectors www molex com enter MLX in the search window with a white nylon body housing pins and sockets crimped on to the end of wires Anemerging standard particularly among ARES and other emergency communications groups is the use of Anderson PowerPole connectors Www andersonpower com click Product Brands These connectors are sexless meaning that any two con nectors of the same series can be mated there are no male or female connectors By standardizing on a single connector style equipment can be shared and replaced easily in the field Molex and PowerPole connectors use crimp terminals both male and female in stalled on the end of wires A special crimping tool is used to attach the wire to the terminal and the terminal is then inserted into the body of the connector Making a solid connection requires the use of an appropriate tool do not use pliers or some other tool to make a crimp connection Some equipment uses terminal strips for di rect connection to wires or crimp terminals of ten with screws Other equipment uses spring loaded terminals or binding posts to connect to bare wire ends Fig 29 12 shows some com mon crimp terminals that are installed on the ends of wires using special tools 29 6 Chapter 29 Molex molded nylon i 4 Terminal amp socket ED Barrier ne SoS sa Moe om PowerPole og e
49. tenna switches antenna tuners and so on RG 58 might be fine fora short patch between your transceiver and SWR bridge but is too small to use between your legal limit ampli fier and Transmatch For more information see the Transmission Lines chapter Hookup wire may be stranded or solid Generally stranded is a better choice since it is less prone to break under repeated flexing Many applications require shielded wire to reduce the chances of RF getting into the equipment RG 174 is a good choice for control audio and some low power appli cations Shielded microphone or computer cable can be used where more conductors are necessary CONNECTORS Connectors are a convenient way to make an electrical connection by using mating electrical contacts There are quite a few connector styles but common terms apply to all of them Pins are contacts that extend out of the connector body and connectors in which pins make the electrical contact are called male connectors Sockets are hollow recessed contacts and connectors with sockets are called female Connectors designed to attach to each other are called mating connectors Connectors with spe cially shaped bodies or inserts that require a complementary shape on a mating connector are called keyed connectors Keyed con nectors ensure that the connectors can only go together one way reducing the possibility H TUNE OMU CAT PGM SW 0t Fig 29 10 The
50. tor the voltage and frequency of which depends on rotational speed Because the generator is directly coupled to the engine the generator s rotational speed is determined by the speed of the engine If the engine is running too fast or too slow the voltage and frequency of the output will be off If everything is run ning at or near the correct speed the voltage and frequency of the output will be a close approximation of the power supplied by the ac mains a 120 V ac sine wave with a frequency of 60 Hz Most standard consumer generators use two pole armatures that run at 3600 RPM to produce a 60 Hz sine wave VOLTAGE REGULATION There are several electronic and mechani cal methods used to regulate the ac output to keep the voltage and frequency values as stable as possible as generator and engine speeds vary because of current loads or other factors Remember astandard generator must turn at a specific speed to maintain output reg ulation so when more power is drawn from the generator the engine must supply more torque to overcome the increased physical magnetic resistance in the generator s core the generator can t simply spin faster to supply the extra oomph Most generators have engines that use me chanical or vacuum governors to keep the generator shaft turning at the correct speed If the shaft slows down because of increasing generator demand the governor hits the gas and draws energy
51. ur Equipment Once you have your equipment and get it arranged you will have to interconnect it all No matter how simple the station you will at least have antenna power and micro phone or key connections Equipment such as amplifiers computers TNCs and so on add complexity By keeping your equipment interconnections well organized and of high quality you will avoid problems later on Often ready made cables will be available But in many cases you will have to make your own cables A big advantage of making your own cables is that you can customize the length This allows more flexibility in arranging your equipment and avoids un sightly extra cable all over the place Many manufacturers supply connectors with their equipment along with pinout information in the manual This allows you to make the necessary cables in the lengths you need for your particular installation Always use high quality wire cables and connectors in your shack Take your time and make good mechanical and electrical connec tions on your cable ends Sloppy cables are often a source of trouble Often the problems they cause are intermittent and difficult to track down You can bet that they will crop up right in the middle of a contest or during a rare DX QSO Even worse a poor quality connection could cause RFI or even create a fire hazard A cable with a poor mechani cal connection could come loose and short a power supply to ground or apply a volta
52. ut 120 seconds and a 100 A load for about 2 seconds There fore it pays to be conservative when select ing the carrying capacities of both wire and fuses Fig 29 22 shows the characteristics of several sizes of automotive fuses 29 2 4 Amplifiers Mobile HF amplifiers have been around for many years and with the advent of high power solid state devices they are common However running high power in a mobile environment requires careful planning Con siderations include but are not limited to e alternator current ratings and battery capacity e wiring in addition to safe currentratings excessive voltage drop will increase IMD e antenna and feed line power ratings e placement and secure mounting in the vehicle e wiring and placing of remote controls See www k0bg com amplifiers html for more information on these topics Before purchasing an amplifier take a close look at your antenna installation and make sure it is operating efficiently Mating an amplifier to a poor antenna installation is counterproductive Here s a rule of thumb applicable to any type of antenna If the un matched input SWR is less than 1 7 1 on 17 morany lower frequency band then itisn t mounted correctly and or you need a better antenna Whatever antenna you use it must be capable of handling the amplifier power level 500 W or more More information on HF mobile antennas and installation techniques may be found in the Antennas chapter
53. vantage of this type is the residue left be hind that might cause corrosion in electrical connectors Another type of fire extinguisher suitable for energized electrical equipment is the carbon dioxide unit CO extinguish ers require the user to be much closer to the fire are heavy and difficult to handle and are relatively expensive For obvious reasons water extinguishers are not suitable for fires in or near electronic equipment AIDS FOR HAMS WITH DISABILITIES A station used by an amateur with physical disabilities or sensory impairments may re quire adapted equipment or particular layout considerations The station may be highly customized to meet the operator s needs or just require a bit of tweaking The myriad of individual needs makes describing all of the possible adaptive meth ods impractical Each situation must be ap proached individually with consideration to the operator s particular needs However many types of situations have already been encountered and worked through by others eliminating the need to start from scratch in every case An excellent resource is the Courage Handi Ham System The Courage Handi Ham System a part of the Courage Center provides a number of services to hams and aspiring hams with disabilities These in clude study materials and a wealth of useful information on their comprehensive Web site Visit www handiham org for more informa tion 29 1 5 Interconnecting Yo
54. ver performance for future reference 29 1 7 Interfacing High Voltage Equipment to Solid State Accessories Many amateurs use a variety of equip ment manufactured or home brewed over a considerable time period For example a ham might be keying a 60s era tube rig with a recently built microcontroller based electronic keyer Many hams have modern solid state radios connected to high power vacuum tube amplifiers Often there is more involved in connect ing HV high voltage vacuum tube gear to solid state accessories than a cable and the ap propriate connectors The solid state switch ing devices used in some equipment will be destroyed if used to switch the HV load of vacuum tube gear The polarity involved is im portant too Even if the voltage is low enough a key line might bias a solid state device in 29 8 Chapter 29 To Positive Line To Negative only Switch To Negative Line Positive only Switch HBKO5_19 25 Fig 29 15 Level shifter circuits for opposite input and output polarities At A from a negative only switch to a positive line B from a positive only switch to a negative line HBKO5_ 19 26 to positive to line positive only switch to negative to line negative only switch Fig 29 16 Circuits for same polarity level shifters At A for positive only switches and lines B for negative only switches and lines BT1 9 V transistor radio battery R1 10 KO 10 14
55. weight The height of tables and keyboards often is not adjustable Placement of computer screens should take into consideration the reflected light coming from windows It is always wise to build into your sitting sessions time to walk around and stimulate blood circulation Your muscles are less likely to stiffen while the flexibility in your joints can be enhanced by moving around Selection of hand tools is another area where there are choices to make that may affect how comfortable you will be while working in your shack Look for screwdriv ers with pliable grips Take into account how heavy things are before picking them up your back will thank you FIRE EXTINGUISHERS Fires in well designed electronic equip ment are not common but are known to oc cur Proper use of a suitable fire extinguisher can make the difference between a small fire with limited damage and loss of an entire home Make sure you know the limitations of your extinguisher and the importance of reporting the fire to your local fire department immediately Several types of extinguishers are suitable for electrical fires The multipurpose dry chemical or ABC type units are relatively inexpensive and contain a solid powder that is nonconductive Avoid buying the smallest size a 5 pound capacity will meet most re quirements in the home ABC extinguishers are also the best choice for kitchen fires the most common location of home fires One disad
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