HP 809C User's Manual
Contents
1. dioe PEE Frequency Fits Equivalent Range GHz Waveguide Flange size in G810B 3 95 to 5 85 2x1 UG149A U C810B 4 90 to 7 05 1 718 x 923 J810B 5 20 to 8 20 1 1 2x 3 4 UG344 U H810B 7 05 to 10 0 1 1 4 x 5 8 UG51 U M810B 10 0 to 15 0 850 x 475 X810B 8 20 to 12 4 1x1 2 UG39 U P810B 112 40 to 18 0 702 x 391 UG419 U 02423 1 Fe al ONUS Model 809C Section H Paragraphs 2 1 to 2 16 SECTION 1l OPERATING INSTRUCTIONS 2 1 ASSEMBLY 2 2 MOUNTING A SLOTTED SECTION 2 3 A slotted section is inserted in the carriage slot side up with the four mounting holes in the slotted section matching the four mounting holes in the car riage Theclearance betweenthe endframe shoulders and the slotted section is about 0 0001 inch and the slotted section must be kept square as it mates with the shoulders CAUTION Remove probe first to avoid damage Do not force slotted section into the end frame 2 4 The top side of the slotted section should meet the four carriage shoulders accurately This can be checked by holding the slotted section in place before the screws are inserted and tipping it slightly A slight clearance may exist under one shoulder but should not exceed 0 002 inch 2 5 Four socket head cap screws HB pari no 3030 0024 which are provided fasten the slotted section to the carriage These screws should be set snugly with a 9 32 across the f2. 2 16 OPERATING CHECKS a With slotted section properly assembled to the probe carriage connect a signal generator of the de sired frequency and a load to the slotted section The load should have an SWR of 2 1 or better b Connect a standing wave indicator to the carriage probe and slide the carriage to observe the standing wave pattern c If the unit has been properly assembled the amplitude of successive peaks of the standing wave pattern should be within approximately one percent of each other When precise measurement is demanded the position of the slotted section may be adjusted slightly within the carriage as follows to equalize the Dial measurement gauges for use with the Model 809C are as follows B C Ames Co Waltham Mass Model 282M L S Starrett Co Athol Mass Model 665M 2 1 Section II Figure 2 1 standing wave peaks With a short connected deter mine which end of the slotted section has the increasing voltage peaks high end Loosen slightly the two screws holding the high end of the slotted section and tighten the setscrew in the middle of the end frame witha 1 16 across the flats Allen wrench Recheck and repeat adjustment if necessary 2 17 MECHANICAL DRIVE 2 18 Although the Model 809C is designed partic ularly for manual applications itis rigidly constructed and may be used in a motor drive application for pro duction test or in cases where standing wave patterns are pres
3. Net 11 4 1b 0 6 kg Shipping 3 Ib 1 4kg Accessories Furnished 11512A Short Type N male 11565A Short APC T Option 11 Both connectors APC 7 11565A APC 7 short supplied Option 22 Both connectors Type N one male one female 11512A and 11511A Type N female short supplied 02423 1 1 1 Model 809C Section I Table 1 1 Table 1 1 Specifications Cont d MODEL 810B WAVEGUIDE SLOTTED SECTION Model G810B J810B H810B X810B P810B Frequency Range GHz 3 95 5 85 5 30 8 20 17 05 10 00 8 20 12 40 12 40 18 00 Waveguide I D in 1 872 40 004 x 1 372 0 002x 1 122 x 0 002 x 0 900 0 002 0 622 0 001 x 0 872 40 002 0 622 0 001 0 497 0 001 0 400 40 001 0 311 x 0 001 Fits Waveguide Size Nom O D in 2x1 11 2x 3 4 11 4 x 5 8 1x1 2 0 702 x 0 391 EIA WR187 WR 137 WR112 WROO0 WR62 Equiv Flange UG 407 U UG 441 U UG 138 U UG 135 U UG 149 U Length in 10 1 4 10 1 4 10 1 4 10 1 4 10 1 4 mm 260 260 260 260 260 Net Weight 1b 2 1 8 2 13 8 11 8 1 8 kg 0 96 0 9 0 63 0 55 0 39 Shipping Weight ib 4 3 2 2 2 kg 1 8 1 4 0 9 0 9 0 9 Slope and Iregularities 1 01 SWR awt Carriage Fits HP 809C Universal Probe Carriage MODEL 447B UNTUNED PROBE Frequency Range 1 8 to 18 GHz HP 816A Coaxial Slotted Line For use with Output Connector BNC female Detector Supplied Dimensions maximum envelope 3 1 2 in long 1 1 8 in diameter 89 x 29 mm Requires 3 4 in 19 1 mm m
4. 1 a ssb
5. number 131 129 and HP 1250 0907 If this contact needs replacement and a new contact is available proceed as follows a Place the instrument so the connector faces down if possible p Tapthe connector lightly and the contact should now protrude slightly Insert the centering pin of the HP contact extractor part number 5060 0236 with the jaws open If this tool is not available an ordinary draftsman s mechanical pencil may be used the end of the jaws may have to be filed to get a good grasp at the very end c Allow the jaws on the tool used to close and pull straight away from the connector without twisting The contact should come with the tool M not repeat the process Do NOT re use the COUPLING SLEEVE SSS SS m ees SUPPORT BEAD 9777 BUILD INNER CONDUCTOR 2977 NI CONTACT Y Pr OUTER CONDUCTOR zz AAT Amphenol APC 7 Connector d Snap in a new contact by pushing a new con tact in place Other tools such as open end wrench HP part number 8710 0877 and spanner wrench HP 5060 0237 are available for working on these connections A contact Amphenol RF Division Danbury Conn 0 316 MIN 0 320 MAX 0 314 MIN S 0 316 MAX DESS MAX Eoee MAX QOS MAX OU 2g ae ene CMLL RS i A e 0 207 MIN B m 0 207 MAX 90TA A 18 ALL DIMENSIONS IN INCHES LU Figure 2 10 Type N Connector 2 12 02423
6. read the distance in centimeters from the right flange face of the slotted section to the probe Since the position of the slotted section varies a small amount during assembly the carriage scale should be adjusted after the slotted section has been assembled Two machine Screws mount the scale to the carriage and can be loosened to adjust the scale The scale position may be checked electrically by placing a shorting plate on the output flange 2 12 A fittingto the rear of the carriage is designed to accept a standard dial type indicator for m ea surements that require precise positioning for ex ample the measurement of null widths of high SWR s or measurement of SWR by the nodal shift method A stop on the rear rod may be adjusted to calibrate a dial indicator to adesired reference A25 millimeter dialindicator with dial graduations of 0 01 millimeter is recommended for this purpose 2 14 Even though the carriage is sufficiently rigid to withstand normal working strains it is desirable under all conditions of measurement to adjust the leveling screws on the feet of the carriage so that the _frame is supported uniformly at all four corners Particular care should be taken with this adjustment when waveguide sections are suspended by a slotted section mounted inthe carriage since anyundue strain could cause distortion and error in measurements 2 15 To adjust the leveling blocks in the mainframe refer to paragraph 2 15c
7. ss se e 2 5 4 2 Typical Setup for Measuring Standing 2 5 Graph Showing Standing Wave Wave Ratio gt e s ee ee ee ete 04 4 Patterns with a Load and Short 2 6 2 6 Summary of Rules for Impedance 5 1 Exploded View of Model 809C 5 0 Measurement s sss ee ee 2 6 5 2 Exploded View of 447B Probe 5 2 LIST OF TABLES Number Title Page Number Title Page 1 1 Specifications 403p wa icm ca dmi 4 1 Test Equipment Required for 1 2 Model 810B Waveguide Slotted Sources 2 3 Performance Testing 4 1 4 2 Setup for Residual SWR Check 4 3 8 1 Reference Designation Index Carriage 9 1 2 1 Recommended Signal Sources 2 3 5 2 Reference Designation Index Probe 5 8 02423 1 un iii Section I Model 809C Figure 1 1 fet Wee MODEL 810B WAVEGUIDE SLOTTED SECTION MODEL 816A COAXIAL SLOTTED LINE MODEL 447B UNTUNED PROBE MODEL 444A UNTUNED PROBE MODEL 442B BROADBAND PROBE MODEL 440A DETECTOR MOUNT e Figure 1 1 Model 809C Universal Probe Carriage and Accessories 1 0 02423 1 Probe Travel 10 cm Model 809C Section I Paragraphs 1 1 to 1 7 SECTION GENERAL INFORMATION 1 1 GENERAL 1 2 The HP Model 809C Universal Probe Carriage is a precision built mechanical assembly designed to operate with a number of interchangeable slotted lines These include HP 810 Series Waveguide Slotted Sections covering frequency ranges f
8. standing wave ratio consists of setting the probe at a voltage maxi mum position and setting the gain of the Model 415B E so that a scale of 1 0 is obtained The carriage is then moved along the line for a voltage minimum and the SWR is indicated directly onthe scale of the Model 415B E This method while straightforward and simple can lead to serious errors under certain con ditions Section III of this manual discusses these errors and suggests techniques for minimizing their effects 2 34 Generally the impedance characteristic of the loadis obtained by measuringthe position of the mini mum in astanding wave pattern A shift in position occurs when known load replaces the load under test For convenience the reference point is usually theloadconnector on the slotted section and the known load is a short circuit or shorting plate 2 3 Section II Figure 2 2 SIGNAL GENERATOR ATTENUATOR Use on atienuator LOW PASS RF FILTER Use when source produces harmonics of the desired signal to reduce re reflections from source and filter Model 808C SWR METER SLOTTED SECTION DEVICE UNDER TEST CARRIAGE 809C A 4 Figure 2 2 Typical Setup for Measuring SWR 2 35 FIXED FREQUENCY MEASUREMENTS Met 2 36 MEASUREMENT OF STANDING WAVE RATIO 37 DIRECT READING VOLTMETER METHOD A detector and direct reading indicator are used in the simplest method for measuring SWR When loose probe cou
9. COUPLING NUT P2818 A I i Keep contacting surfaces smooth and clean Irregularities and foreign particles can degrade electrical performance CONTACTING SURFACES 2 Protect the contacting surfaces when the con nector is not in use by leaving the coupling sleeve extended 3 Use lintless material and or firm bristled brush such as tooth brush for cleaning Ifa cleaning fluid is needed use isopropyl alcohol IMPORTANT Do not use aromatic or chlori nated hydrocarbons esters ethers terpenes higher alcohois ketones or ether alcohols such as benzene toluene turpentine dioxane gasoline cellosolve acetate or carbon tetra chloride Keep exposureof the connector parts to both the cleaning fluid and its vapors as brief as possible Section II Figure 2 10 Model 809C a REPLACING AMPHENOL APC 7 CENTER CONTACT Through wear or damage the contact in the center conductor may need replacing This contact is a small four pronged collet which snaps into arecess in the center conductor This contact is normally held in by the spring actionof the four prongs With a magnifying glass examine this contact to deter mine if it needs replacement DO NOT REMOVE THIS CONTACT FOR INSPECTION it may be dam aged by removing The contact should be free of burrs or wear and the prongs should be equally spaced If the contact is removed do NOT re use it it may be damaged by removal This contact is Amphenol part
10. Eq RELATION tL BETWEEN Eg AND i Eg AND EL t Ea EN IN PHASE GIVE MAX SWR Eswr VALUE SWR Emax i SWR eo WE swr swi E STA CELADUUSTED e SEPARATELY E IVE SW aI ms E SWR2 N n3 Re Emax D Ea R She ESWRo sosc a 9 Figure 2 3 a Typical set up using sliding load b Relation of incident and reflected voltages when making measurements with a sliding load 2 43 The phase of reflection Eq can in effect be adjusted by changing the position of the probe carriage on the slotted line Similarly the phase of the reflec tion E canbe adjusted by positioning the sliding load In the first SWR measurement the phases of E and E are adjusted by positioning the probe carriage and load so that the two reflections reinforce each other his arrangement gives the highest obtainable value of reflected voltage and thus the highest SWR The SWR has the value E E at Ej E E at E SWR 2 44 Inthe second SWR measurement when the probe is returned to the position of the maximum the phase of only E is adjusted Under this condition the reading nds the value Ej E SWR a E E Ea E Since the reflected waves are smallin magnitude this second SWR reading is essentially the SWRofthe sliding load In case of question the SWR can also be calculated from the more accurate expression SWR 1 SWR SWR SWR 1 2 4 02423 1 Secti
11. HP 816A Coaxial Slotted Sections Probe Required HP 447B Untuned Probe HP 444A Untuned Probe or HP 442B Broadband Probe Calibration Metric Vernier permits readings to 0 1 mm Provision for dial gauge installation Leveling Screws Knurledthumb screws provided on all four carriage legs Accuracy Whenused with waveguide sections standing wave ratios to 1 02 can be read easily Slope error of slotted sections canbe eliminated by adjustment Dimensions maximum envelope 8 7 8 in long 6 13 16 in wide 5 13 10 in high 226 x 174 x 148 mm Weight Net 4 lb 1 8 kg Shipping 4 Ib 2 3 kg MODEL 816A COAXIAL SLOTTED LINE Frequency Range 1 8 to 18 GHz with HP 447B Probe Impedance 900 x 0 22 Carriage Fits HP 809C Universal Probe Carriage Connectors One APC 7 one Type Nfemale TypeN connector is stainless steeland mates compatibly with Type N connectors whose dimensions conform to MIL C 39012 or MIL C 71 Either end can be connected to the load shorting connectors furnished for load phase angle determination Residual SWR and Reflection Coefficient APC 7 Connector 1 8 to 8 GHz lt 1 02 0 01 8 to 12 4 GHz X 1 03 0 015 12 4 to 18 GHz lt 1 04 0 02 Type N connector 1 8 to 8 GHz lt 1 04 0 02 8 to 12 4 GHz 1 05 0 024 12 4 to 18 GHz lt 1 06 0 029 Slope and Irregularities 0 1 dB per half wavelength 0 2 dB maximum cumulative Length 9 3 4 in 248 mm Weight
12. LTO CALIFORNIA U S A 02423 1 00809 90004 Printed AUG 1967 Model 809C Table of Contents Lists of Illustrations and Tables TABLE OF CONTENTS Be k Section Page Section Page I GENERAL DESCRIPTION e elel nt THEORY OF OPERATION 3 1 3 1 Introduction s s 6 s e s e e 3 1 1 1 General eee ee ee ee del 3 3 Theory of Operation es v 3 1 1 4 Mechanical Inspection 1 1 3 8 Signal Sources ee eee 3 1 1 6 Accessories Available 1 1 14 FM e c rc Rt n Gg S n ng nS Sel 3 17 Spurious Signals s es res 3 2 8 22 Probe Penetration 3 2 Hi OPERATING INSTRUCTIONS e 2 1 3 27 Location of Minima s 3 2 3 29 Detector Characteristics 3 3 2 4 a Adsdniply vereda Udo bd LEY oe High ee he See PON T 2 2 Mounting a Slotted Section 2 1 Tue UO NEUE M ME 2 1 Probe se s eS oo on n n n Hl IV PARTS BREAKDOWN e eee eee eetl m du oy 4 1 Introduction ss s od 2 16 o tine Check 2 1 4 3 Preventive Maintenance s 4 1 peratng ROCER e tom rt 4 5 Performance Check 4 1 2 17 Mechanical Drive amp 2 2 20 Critical Mounting Dimensions 2 2 4 6 Purpose s sis ed 0007 aah 2 22 Equi t Consid a 2 2 4 8 Test Equipment Required 4 1 Equipment Considerationg s t rogi 4 10 Model 816A s e esse 4l e Sigra Source a ern tn 2 3 4 11 Characteristic Impedance 4 1 26 ow pa
13. RE The technique for performing an impedance measurement is as z follows L i j SWR tan X SWR jtan X a Connect the load under test tothe slotted section see Figure 2 2 and measure the SWR and the position of the minimum in the standing wave pattern where SHORT LOAD Ad Shift in centimeters of the minimum point when the short is applied Ad takes a positive sign when the minimum shifts toward the load am d ges Ad takes a negative sign when the minimum shifts toward the generator t One half line or guide wavelength It 9 X is the distance in centimeters as A Figure 2 5 Graph Showing Standing Wave measured between two adjacent Patterns with a Load and Short smi nima IF MINIMUM SHIFTS X LOAD EQUALS Z SWR LOAD MINIMUM MINIMUM WILL SHIFT TO THIS REGION IF LOAD IS GENERATOR IS INDUCTIVE 1S CAPA aah 2 4 RO IF MINIMUM DOES NOT SHIFT LOAD EQUALS Z SWR Figure 2 6 Summary of Rules for Impedance Measurement 2 6 02423 1 y Model 809C 2 51 RULES FOR IMPEDANCE MEASUREMENT The calculations above arebased upon the assumption that no losses occur in the transmission system For laboratory setups where line lengths are short this assumption is customary It is also assumed that the characteristic impedance Z for the lines is entirely resistive Since the mini
14. ave indicator is tuned generally this is a 1 kHz square wave The signal generator must have an internal source of 1 kHz modulating voltage or must have a modulating voltage input Recom mended signal sources are shown in Table 2 1 2 26 LOW PASS FILTER 2 27 Connect filter at the signal source output to eliminate harmonics The HP Model 362A series filters that have at least 40dB attenuation in the stop band are suitable Model 281B waveguide to coax adapters must be used with these waveguide filters when working with coaxial slotted sections 2 28 PAD 2 29 There should be isolation between the signal source and the slotted section The HP Model 375A series or the HP Model 382A series Variable Attenu ators are recommended for waveguide the HP Model 8491A or 8491B 8492A Attenuators and Model 354A Step Attenuator for coaxial applications 02423 1 2 30 INDICATOR 2 31 A high gain tuned voltmeter should be used Since the crystal should be operated in its square law region the indicator should have square law cali bration The HP Model 415B E Stancing Wave Indi cator is suitable The Model 415B input normally is tuned to 1 Hz but plug in filters tuned to frequencies of from 315 to 2020 hertz are available at nominal cost Alternatively adc oscilloscope or X Y recorder can be used as a dc indicator modulation is not needed in this case 2 32 BASIC MEASUREMENT TECHNIQUES 2 33 Basically the measurement of
15. e scale cor respondingto 0 125 wavelengths toward the generator Witha compass point at the center of the chart set the arm to2 0 SWR swing arm 180 to point A ME minimum position draw an arc and the line EAE point B This is the normalized impedance z 3 Multiply 0 8 j0 6 by the characteristic impe e z3 to find the true value 2 7 Section II Model 809C Figure 2 7 IMPEDANCE OR ADMITTANCE COORDINATES m oar D rni BO9C A 3 2i1eig a t te 2 x a ess sle jacsists mena qunm tS STE ea Estone courouent A h Semouoveravaz courant 2 z T zj 33955 RADIALLY SCALED PARAMETERS a d i uu PAD o sem WWE HE See S u i2 I3 Me 36 AB LU NEN Oat JURE INE PE FUSE AN r3 ot WU aS TTS 18 0 1B 03 2 Figure 2 7 Smith Chart 2 8 02423 1 Model 809C Section II Figure 2 8 ai ban Figure 2 8 Swept Slotted Line SWR Setup 2 56 EFFECT OF RESIDUAL REFLECTIONS The and the minimum SWR that will be read is residualreflections in thetransmissionline will cause an error in reading the SWR of a load and also in 2 3 measuring the shift of the minimum when a short is L or r applied The equations showing the net result are 7r 71 i rather complicated but can be summarized easily as follows Let residual SWR r whichever ratio is greater than 1 K Let true load SWR o a 2 57 The maximum error in determ
16. ented on an oscilloscope The positioning knob and pinion gear may be removed for such applications permitting the carriage to run freely The carriage may be connected to a motor drive unit that provides a reciprocating motion The reciprocating motion should be limited to a few cycles per second 2 19 For oscilloscope or X Y recorder presentation mount a contact on the back side of the movable carriage to wipe a fixed resistance cardas the carriage moves With a de voltage supply connected to the resistance card the contact receives voltages proportional tothe Model 809C linear displacement of the carriage This voltage is applied to the horizontal sweep of an oscilloscope or X Y recorder allowing the standing wave pattern to be presented accurately both in amplitude and position 2 20 CRITICAL MOUNTING DIMENSIONS 2 21 Slotted sections may be made for use with the Model 809C to accomodate special waveguide sizes Figure 2 1 shows the critical mounting dimensions re quired for the machining of any special slotted sections 2 22 EQUIPMENT CONSIDERATIONS 2 23 Excessive probe penetration is a major source of error in slotted line measurements when measuring standing wave ratios of 10 1 or less Probe penetration can be considered as an admittance shunting the line the effect becoming greater as probe penetration is increased As probe penetration is decreased how ever the amplitude of the signal drops for a good read
17. er position on the X axis of theoscilloscope asthe carriage is moved the storage oscilloscope willstore a smeared pattern of which the envelope width is a function of SWR versus frequency he oscilloscope presentation is linear the SWR is E max a 2 SWR x ANRT min However it is better if the vertical presentation is logarithmic The display height will then be E 3 B max _ log15E max log 0E min logy En log 9SWR The widest part of the pattern will be its maximum SWR This canbe converted to voltage ratio from any standard table relating decibles to voltage ratio or the SWR can be calculated from SWR log 5 3B s For instance a reading of 1 65 dB gives an SWR of 1 21 This technique allows SWR to be measured very rapidly and accurately 2 62 To level the sweep oscillator so that the power Xs probe frequency response throughout the band 48A Slotted Line Sweep Ad apter is used as a broadband coupler detector in the leveling feed back loop see Figure 2 8 The 448A consists of a short section of the 816A Slotted Line andadetector identical 2 10 Model 809C to the oneused inthe slotted line These two detectors are matched pairs and are both provided with the 448A CAUTION Replace these detectors only in matched pairs 2 63 OPERATION 2 64 After both probes are inserted into the 448A Slotted Line Sweep Adapter arid the 809C Carriage the sweep oscillator power level is reduced
18. ess than 1 03 up to 12 4 GHz and less than 1 04 through 18 GHz with the APC 7 connector 2 68 To minimize the effect of error due to reflections from the probe in a slotted line the least amount of probe penetration should be used consistent with the sensitivity of the display unit For further information see Application Note 84 obtainable from your nearest HP office 02423 1 Model 809C M Ne COUPLING SLEEVE USE To Connect i Onone connector retract the coupling sleeve by turning the coupling nut counterclockwise until the sleeve and nut disengage 2 On the other connector fully extend the coup ling sleeve by turning the coupling nut clock wise To engage coupling sleeve and coupling mut when the sleeve is fully retracted press 3 Push the connectors firmly together and thread the coupling nut of the connector with retracted sleeve over the extended sleeve 4 Do NOT tighten the other coupling nut since this will tend to loosen the electrical connection To Disconnect 1 Loosenthe coupling nut of the connector show ing the wider gold band WIDER BAND 2 IMPORTANT Part the connectors carefully to prevent strikingthe inner conductor contact 02423 1 gX c CENTER CARE back lightly on the nut while turning it clockwise _ Section Ii Figure 2 9 t ET A CONDUCTOR SUPPORT BEAD INNER CONDUCTOR CONTACT MECHANISM OUTER CONDUCTOR
19. he load In a typical SWR measurement moving the load will cause the meter pointer of the SWR meter to vary as the phase ofthe 2 41 To measure the SWR ofthe transmission system the sliding load is connected in place of the usual load at the end of the system Then adjusting both the position of the probe carriage on the slotted section and the position of the sliding load the highestobtain able SWR is sought and measured This measurement requires some care since the settings are interde pendent A second SWR measurement is made To make this measurement first return the probe to the position of the original maximum or peak Adjust the Sliding load to obtain a minimum reading on the SWR Meter maximum needle deflection to left The load Should be adjusted while the probe carriage is still positioned at the point of the former maximum Read SWR on SWR Meter A second SWR smaller than the firstis obtained If the first SWR readingis SWR and the second reading is SWR the SWR of the trans mission system is SWR 2 42 The above measurements are shown in Figure 2 3 which represents the voltage waves in the trans mission system in vector form Vector E the incident wave travels down the system and a partial reflection E occurs at the device under test A second parti reflection Ex occurs at the sliding load SWR 02423 1 d pas Model 809C DISCONTINUITY UN DEVICE UNDER TEST e UNKNOWN E
20. ing a signal level must be high enough to be above the combined noise of crystal and indicator Thus when measuring small standing wave ratios equip ment used in the measurement system should have features that will contribute to obtaining a useful signal with probe penetration as slight as possible i log l 7 500 005 8 32 THREAD TYPICAL 8098 8 2 Figure 2 1 Critical Mounting Dimensions 2 2 02423 1 i Model 809C Section II Table 2 1 Table 2 1 Recommended Signal Sources Ss Source of Su Frequency Range MHz Signal Source HP Model Number Mod Volts Mod Volts Source HP 1 800 4 000 616A B UHF Signal Generator external 211A Square Wave Gen 3 800 7 600 618B SHF Signal Generator internal 7 000 11 000 620A SHF Signal Generator internal Li 10 000 15 500 626A SHF Signal Generator internal 15 000 21 000 628A SHF Signal Generator internal 2 000 4 000 8692A B w 8690A Sweep Oscillator internal 4 000 8 000 8693A B w 8690A Sweep Oscillator internal 8 000 12 400 8694A B w 8690A Sweep Oscillator internal L 12 000 18 000 8695A w 8880A Sweep Oscillator internal 3 Pr g 2 24 SIGNAL SOURCE 2 25 The source used should be capable of delivering at least 1 milliwatt of power output and have an output low in harmonics and incidental FM The RF output must be amplitude modulated at the frequency to which the standing w
21. ining the shift of the minimum will be c 1 2 wavelengths and this maximum error will decur only with certain purely i Ler reactive loads Then the maximum SWR that will be read is 02423 1 2 9 Section II Paragraphs 2 58 to 2 68 2 58 SWEPT FREQUENCY MEASUREMENTS 59 The 809C 816A 448A combination can also be sed for swept frequency measurements Many times out of specification holes canbe missed with single frequency measurements Swept measurements will reveal these holes if the sweep is slow enough 2 60 Swept frequency techniques are fully covered in Application Notes 65 and 84 available from your nearest HP field office This discussion will cover only the use of slotted lines in Swept frequency SWR measurements 2 61 Swept frequency SWR measurements differ from fixed frequency measurements in that a Sweep oscil lator is used as a signal source and a storage oscil loscope is used as the recording device a standard oscilloscope could also be used if a time exposure picture of the trace can be made Allpossiblevalues of SWR are displayed by movingthe slotted line probe over at least a half wavelength A vertical line is traced out and stored onthe storage oscilloscope The top of the line represent the maximum of the SWR pattern of the device under test and the bottom repre sents the minimum of the SWR pattern at this particular frequency At a different frequency another vertical line will be traced atanoth
22. lats Allen wrench taking care that the slotted section does not bind in the carriage as the screws are set 2 6 With the slotted section properly secured to the carriage about 0 010 inch clearance will exist between the movable carriage and the top of the slotted section with the unit assembled the movable carriage should slide freely from one end to the other 2 7 PROBE 2 8 With the slotted section properly secured to the carriage a suitable probe may be inserted in the hole centered on the movable carriage Be sure that the tip of the probe is centered inthe slot This may be checked in waveguide by sighting down the inside of the slotted section and moving the adjustable carriage with the probe along the slot It is not necessary for the probe to be absolutely centered but the probe tip must not touch the slot edge 2 9 The probe depth on slotted section detector mounts maybe adjusted by unlocking the knurled bead on the mount itself Probe depth adjustment may be made by varyingthe depth of the detector element and relocking the knurled head At some frequencies it will be found that probe depth has a marked effect on the tuning of the detector If this condition is en countered readjust the depth of the probe for satis factory but loose coupling minimum penetration 02423 1 2 13 LEVELING 2 10 CARRIAGE SCALE 2 11 For waveguide sections the scale and vernier on the front of the carriage are aligned to
23. ma occur at each half wavelength the maximum shift that need be con sidered is a quarter wavelength on each side ofthe initial reference position Several rules may be for ulated in considering the concept a The shift in the minimum after theload has been shorted is never more than x A 4 b If shorting the load causesthe minimum to move toward the load a capacitive component exists in the load c If shorting the load causes the minimum to shift toward the generator an inductive component exists in the load d If shorting the load causes no shift in the mini mum a completely resistive load exists equal to z SWR e If shorting the load causes the minimum to shift exactly 4 4 the load is completely resistive and has a value of 26 x SWR i When the load is shorted the minimurfwill always be a multiple of 4 2 from the load These rules are summarized in Figure 2 6 2 52 IMPEDANCE MEASUREMENT AND THE SMITH CHART Impedance cannot be measured directly X is only by using a Smith Chart that measurements of SWR made with a slotted section can betranslated into needed information concerning impedance without resorting to lengthy and laborious calculations See the Appendix for an explanation of the Smith Chart 2 53 The results given in the examples above may be found by using the Smith Chart In addition any shift not only just exact quarter wavelengths can be computed by use of the Smith Chart With the same
24. omputing SWR 2 47 IMPEDANCE MEASUREMENT 2 48 At frequencies where the slotted section is useful transmission systems are electrically long and it becomes necessary to refer impedance to an arbitrary plane This plane may be located anywhere along a transmission system but the end of the slotted section is chosenfor convenience The general procedure for measuring impedance is to measure the SWR produced by the load upon the system and also the shift in position of that SWR pattern when the load is replaced by a short A waveguide shorting plate would be used with the Model 809C 2 5 Section II Model 809C Figures 2 5 and 2 6 D V In the discussion which follows all impedances b Replace the load with a shorting plate at the wi be Considered as normalized to the character end of the slotted section istic impedance of the slotted section Normalization consists of dividing all impedances bythe character c Determine the new minimum position with the istic impedance of the transmission line In the line thus shorted following discussion all normalized mpedances wil be represented by lower case type In the normalized d The normalized load impedance may be computed system the transmission line willhave a characteristic by the formulas below refer to Figure 2 5 or ona impedance of unity Smith chart may be entered with the SWR and wave lengths of minimum shiftdirectly to obtain impedance 2 50 MEASUREMENT PROCEDU
25. on H Figures 2 3 and 2 4 2 45 Forsmallvalues of SWR the above expression canbe approximated by SWR Since the denominator is almost 1 In this case the SWR can be measured by adjusting for maximum SWR setting the SWR to 1 0 and then moving the carriage and the sliding load for a minimum Repeat these adjustments as there may be some interaction The reading on the SWR meter is now the SWR for small values of SWR 2 46 DOUBLE MINIMUM METHOD This method is employed when it is desired to measure a large SWR It is based on the fact that the shape of an SWR pattern at minimum point wil approximate a parabola when the magnitude of the SWR exceeds 10 1 The method involves determining the shape of the particular curve under measurement and calculating the SWR The procedure is normally as follows Slidethe carriageto obtain a minimum point and adjust the indicating meter foraconvenient reading b Locate the point on each side of the minimum where the power output level is twice that of the minimum 3 dB c Determine one wavelength of the frequency of interest on the line or guide One half wavelength on the line is equal to the distance on the scale between two adjacent minima Twice the quantity would be one wavelength of the carrier frequency A g 7 a Compute the SWR by referring to Figure 2 4 POWER AT PROBE RO CENTIMETERS PROBE POSITION Figure 2 4 Graph Showing Double Minimum Method for C
26. oo d 8096 UNIVERSAL PROBE CARRIAGE QPERATING AND SERVICE MANUAL HEWLETT i PACKARD CERTIFICATION The Hewlett Packard Company certifies that this instrument was thoroughly tested and inspected and found to meet its published specifications when it was shipped from the factory The Hewlett Packard Company further certifies that its calibration measurements are traceableto the U S National Bureau of Standards to the extent allowed by the Bureau s calibration facility WARRANTY AND ASSISTANCE All Hewlett Packard products are warranted against defects in materials and workmanship This warranty applies for one year from the date of delivery or in the case of certain major components listed in the operating manual for the specified period We will repair or replace products which prove to be defective during the warranty period No other warranty is expressed or implied We are not liable for consequential damages For any assistance contact your nearest Hewlett Packard Sales and Service Office Addresses are provided at the back of this manual Al S OPERATING AND SERVICE MANUAL MODEL 809C UNIVERSAL PROBE CARRIAGE SERIAL 1 AND ABOVE with Model 816A Coaxial Slotted Line Model 810B Waveguide Slotted Section Model 447B Untuned Probe Model 444A Untuned Probe Model 442B Broadband Probe Model 440A Detector Mount Copyright HEWLETT PACKARD COMPANY 1501 PAGE MILL ROAD PALO A
27. ounting hole Weight Net 6 oz 0 17 kg Shipping 1 Ib 0 45 kg Discontinuity due to slot results in SWR of less than 1 01 Amphenal RF Connector Division of Amphenol Corp Danbury Conn These connectors are 7mm bi sexual connectors any two of which mate with each other MODEL 444A UNTUNED PROBE Frequency Range 2 6 to 18 0 GHz 4 to 18 0 GHz with HP 816A Output Connector BNC female Detector Supplied Accessory Furnished 11506A Probe Tip Kit 8 Tips Dimensions probe flush with housing 1 1 4 x 2 1 16 in 32 x 52 mm Weight Net 60z 0 17 kg Shipping 8 oz 0 23 kg 1 2 02423 1 Model 809C Table 1 1 Specifications Cont d Section I Table 1 2 Table 1 2 Model 810B Waveguide Slotted Sections MODEL 442B BROADBAND PROBE Frequency Range 2 6 to 18 0 GHz 4 to 18 0 GHz with HP 816A Dimensions probe flush with housing 1 1 4 x 8 in 32 x 79 mm Weight Net 60z 0 17 kg Shipping 8 oz 0 23 kg MODEL 440A DETECTOR MOUNT Frequency Range 2 4 to 12 4 GHz Detector not supplied 1N21 to 1N23 silicon crystals or Type 821 barratter Tuning Single stub Connectors Type N male RF input BNC female detector output Dimensions 1 3 16 x 2 13 16 x 4 1 2 in 21x 72x ii4 mm stub adjustable to 613 16in 11312m2 1 Weight Net 50z 0 14kg Shipping 11b 0 45 kg Jet
28. pling is maintained this method is suffi eientlyaccurateforthe measuremerntofmoststanding wave ratios up to 10 1 2 38 FIXED LOAD METHOD Connect equipment as shown in Figure 2 2 and proceed as follows a Slide the carriage along the slotted section and locate a voltage maximum position Tune probe detector circuit if tuneable for maximum voltage b Adjust probe depth for the least coupling that will allow a reading on the Model 415B E with the 415B E RANGE switch set at 40 dB c Adjust GAIN control on the Model 415B E so that the meter indicates 1 0 d Slide the carriage along the slotted section to find voltage minimum position DO NOT retune probe or detector circuit i e Read SWR directly on the meter scale of the Model 415B E in conjunction with the Step attenuator RANGE switch 2 39 SLIDING LOAD METHOD for use with two port devices The previous method measures the l reflection incident plus any residual in slotted s plus that of load The reflection of the load can be eliminated by the use ofa sliding load The instru ment setup is identical with the previous one except that the device under test is terminated in a sliding load 2 4 reflection is varied 2 40 Reflections from the load can be distinguished from those caused by a discontinuity in the transmission system A discontinuity causes a fixed phase reflec tion from the movable load can be made to occur in any phase by moving t
29. rom 3 95 GHz to 18 0 GHz and the HP Model 816A CoaxialSlotted Line 1 8 GHz to 18 0 GHz This carriage may also be used with the older Model 806B in the 3 0 to 12 0 GHz region 1 3 The Model 809C greatly simplifies waveguide measurements over a number of frequency bands as it eliminates the need for a probe carriage for each waveguide band and waveguide sections can be inter changed in 30 seconds or less It can be used with HP Model 444A Untuned Probe HP Model 440A De tector and MHz Model 442B Broadband Probein com bination and the Model 447B Untuned Probe The Table 1 1 unit has centimeter scale with a vernier reading to 0 1 millimeter Provision is also made for mounting adial gauge when more accurate readings are required The probe carriage moves on two ground stainless steel rods and aconventional ball bearing forms the third point of suspension 1 4 MECHANICAL INSPECTION 1 5 Unpack the instr ment upon receipt and inspect it for signs of physical damage If there is any ap parent damage file a claim with the carrier and re fer to the warranty page inthis manual See Paragraph 4 5 for performance check procedures 1 6 ACCESSORIES AVAILABLE 1 7 MODEL 810B WAVEGUIDE SLOTTED SECTIONS Waveguide slotted sections for use with the Model 809C Universal Probe Carriage are listed in Table 1 2 Specifications MODEL 809C UNIVERSAL PROBE CARRIAGE Carriage Mounts all HP 810B Waveguide Slotted Sec tions and
30. rt of a wavelength determined in step g Choose proper scale toward generator or toward load i With the compass point at the center of the Smith Chart point 1 0 on the zero reactance line set the compass arm to the figure corresponding to the SWR on the zero reactance line j Swing the compass arm to touch the line drawn in step h The point where the compass arm touches the line is the impedance of the load in normalized form k To find the actual impedance multiply the re sult in step j by the characteristic impedance Zo 2 54 The above procedure can be clarified by means of the following example Suppose that a load is con nected to the slotted line and found to have a SWR of 2 1 and that the scale reading onthe carriage is 10 cm On removing the load and applying a short note this order the scale reading onthe carriage atthe minimum is now 11 25 cm the shift being measured towards the generator end of the line The frequency of operation is 3 0 GHz or a wavelength of 10 cm Shift of minimum voltage 11 25 10 10 0 125 wavelengths X and from the formula eos 1 jo tan BX Lo j tan X where B we derive 7 EE 1 j2 tan 77 n 1 42 L 2 jtan H 0 8 j0 6 normalized impedance 2 58 To calculate the above by means of the Smith Chart draw a line see Figure 2 7 from the center of the chart point 1 0 along the zero reactance line tothe circumference through a point on th
31. setupas used for measuring SWR proceed as follows a With the load connected slidethe carriage along the slotted line and locate avoltage maximum position Tune probe detector circuit if any for maximum voltage Note 809C scale reading b Adjust probe depth for the least coupling that will allow a reading on the SWR Meter with the meter RANGE switch set to 40 dB c Adjust GAIN control on SWR meter so that the meter indicates 1 0 d Slide the carriage along the slotted line to find a voltage minimum position Do NOT retune probe detector circuit Note 809C scale reading e Read SWR directly on the SWR meter scale in conjunction with the RANGE switch see instruction manual for SWR meter 02423 1 Section II Paragraphs 2 51 to 2 55 f Replace theload with a short Slide the carriage along the slotted line to find another voltage minimum position Note the scale reading on the carriage and whether the shift was toward the signal generator or toward the load g Determine the decimal fraction part of a wave length that the minimum has shifted by subtracting the scale readings on the carr age of the two minimums and dividing the result by wavelength of the frequency under test Wavelength em 3x1010 frequency Hz h Witha ruler draw aline on the Smith Chart from the center point 1 0 onthe zero reactance line to the circumference through the point on the outside scale corresponding to the decimal fractional pa
32. ss Filter e e 2 3 4 18 Residual SWR 4 3 2 28 Pad ee we ww ew H grt 5 EIE QT hat P 4 21 Model810B 2 ee eee 4 4 2 30 Indicator s s sos es e e 223 4 22 Slope and Irregularities 4 4 2 32 Basic Measurement Techniques 2 3 A pe d P MEE 2 35 Fixed Frequency Measurements 2 4 2 36 Measurement of Standing wave V REPLACEABLE PARTS 2 4 e 2 5 1 Ratio nus 2 41 Impedance Measurement w 12 5 ey 51 Replacement of Parts e s 5 1 gm 2 58 Swept Frequency Measurements 2 10 T 2 63 Operation ss sa eror 2 10 APPENDIX 1 ww ffex ciel lio 2 65 Errore a h ay euna a eS 2 10 APPENDIXI Sige Aaa een es H 1 LIST OF ILLUSTRATIONS Number Title Page Number Title Page 1 1 Model 809C Universal Probe 2 1 Smith Chart s s eee ee ee n t n 22 8 Carriage and Accessories 1 0 2 8 Swept Slotted Line VSWR Setup 2 9 2 9 APC 7 Connectors s 4 e eet 2 11 2 1 Critical Mounting Dimensions 2 2 2 10 Type N Connector gt pr 2 2 Typical Setup for Measuring SWR 2 4 2 8 a Typical setup using sliding load 3 1 Plot of Bigh SWR Field Pattern b Relation of incident and reflected a With No FM b With Moderate FM 8 2 voltages when making measurements with a slidingload e s s e es e 2 8 4 1 Setup for Measuring Characteristic 2 4 Graph Showing Double Minimum Method Impedance eee rere 24 0 for Computing SWR s s
33. until the output power is leveled as indicated by the leveling light on the oscillator or the oscilloscope presentation To adjust the output of thedetector to be within its square law range 2 Set the oscilloscope for linear presentation and 1 mV cm sensitivity Place the device to be tested on the end of the slotted line start the sweep and position the carriage for maximum voltage on the oscilloscope Set the probe for a 5 cm trace 5 mV at maximum signal b To operate with the device to be tested connected to the Siotted line set the oscilloscope for logarithmic presentation and move the carriage as the frequency is swept rapidly Readout is directly in decibels of SWR SWR log al dB DI Wd M n For further information consult the Model 817A System manual supplied with the Model 448A 2 65 ERRORS 2 66 Since the oscilloscope is calibrated interms of Square law operation of the detector the signal level from the detector must be below 5 mV for a square law error small enough lt 0 05 dB to be neglected This can be checked easily on the oscilloscope by switching to the linear mode of operation and measuring the output voltage from the detector with known step increases in power The error shown on the oscil losocpe should be 0 02 dB dB or less 2 67 The residual SWR of the slotted line is the limiting error The totalresidual SWR including line slope for the 816A Slotted Section and 809C Carriage is l
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