IIeceiViq CoqVerters NC Frequeqcies youve done some electronics work can find way around schematic heres building pro ject useful device converter allows listen RC fre quency portable radio club should have U John R Lange WOULD YOU LIKE able monitor RC frequency before fly chase down interference check giltches Would like sure some elses transmit ter impound area car hasnt left get glitched would like sure interference got am ham radio operator fly RC 6 meters 53 MHz wanted check band before flying since 6 meters can fested ignition engine noise amateur FM repeaters other things devel oped -this receiving converter circuits ARRL Radio Amateurs VHF Manual Anyone has built Heathkit Ace kit ought able build Most parts can easily obtained local Radio AC Frequency Monitor can easily mounted under car dash Just swap plugs switch between RC frequencies broadcast stations 4 METER AND 6 METER RC FREQUENCY CONVERTER IN 5 I/4x3Mx2 I/8 ALUMINUM BOX WITH UNDER DASH MOUNTING BRACKETS RADIO eOe eWe eOe ANTENNA 0 4 meter shown 6 meter has no 72-75 switch 2 0 eOe INPUT scale inches OL........1 3 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER PARTS LAYOUT IN 5 1/4 x 3x2 I/B ALUMINUM BOX BUDD CU 210GB CU-3006A RADIO SHACK 270-238 LMB 780 ALECTRO H4T741l/2x5/8cutout shield socket coil leads away chassis go gates drains leads closest chassis go terminal strip ground lugs bypass capacitors Cb Shack store receiving crystals can mallordered JAN Crystals International Crystals Addresses appear end article receiving converter can built either two ways version small mini box mounted under dash car uses cars whip antenna power fuse block Its connected car AM radio radio tuner selects chan nel want listen puts out car speaker listen radio simply turn off converter second version portable con tains its own pocket-size AM receiver 1 C U Cq o 10 0 0 U 0 0 S2 omitted 6 meter Cape inside nverters crystal iscover area rO between gate ground lug oNEINcNSCALE second version has seven-position rotary switch connected seven crystals can tune seven RC frequencies 4-me ter RC band way tune TV set first converter 6 meters hooked up car radio has two-FET-transistor cascode RF amplifier stage FET transistor mixer 52 MHz crystal-controlled FET transistor oscillator use 2-ft coaxial extension lead Moto rola male plugs connect car radio cord Part No 12-1314 Radio Shack listen RC frequencies unplug car antenna lead back antenna jack J3 plug front input Ji turn 36 Model Aviation eR @eQe e ee0 ONeBrW7208 680 01087216 760 0408 7224 840 ______Or-SO 7240 VoSO 7232 920 OFF727500-08 7296 1560 shielduse bottom hole 191of ground lugInsulat cbDL33Output RFC Cb4 RFC LI stand end wisleeveshield use sleevin 4-40 check clearanceY2 antennato fuse center pin tobngsleeving1-I25to shield use bottom hole gnd lugi-I45v 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER INTERNAL SHIELDS round off use 5052-H 32 sheet aluminum corners 0 0 o make bends vise dashed lines holes 3/32 diameter 10 A-I converter tune car radio tween 1100 1500 AM dial gives 531 MHz 1100 535 1500 pre-set two radio push-buttons correct spot two RC frequencies use just hit buttonjust like dialing AM station converter setup 4-me ter band 72 76 MHz works same way 4-meter converter can pick up sev en RC frequencies two receiving crystals Since first six frequencies tween 72080 72960 MHz less MHz apart 714 MHz crystal con verter local oscillator will aliow tune ali between 540 1600 radio diaL seventh frequency 75640 picked up switching 74640 crystal appears 1000 dial enough range either side bands receive adjacent interference sources get new frequencies hope tune weli portable converter has small under$10 Radio Shack AM pocket portable radio catalog number 12-171 12-172 tuned 1000 dial seven re ceiving crystals converter 1 MHz low corresponding RC frequency mounted poles rotary switch nine-volt battery series two AA pencells gives 12 volts needed convert er radio course has its own battery might consider building circuit aluminum box chassis case small car radio whip antenna instead pocket portable radio would allow power whole works 12-volt Gel Cell Ni-Cad pack also eliminates AM broadcasts pocket portable radio alignment G C6 I5ch pf__ --12v PORTABLERFC v--Gb OUTPUT FOR POCKET RECEIVER FUSE HOLDER MOUNTING DETAIL 25A fuse to~yJ424 scaleinchesIlockwt~T7i&I 0I23 Um~hiU LFLJ4-40x3/4 BOTTOM VIEW OF TRANSISTORS SG D DQ SQgroundD casecase round 2N5485 2N5486 ECG -312 Ddrain Ssource 2N4416 Ggate will occasionally pick up stations close 1000 dial Construction under-dash version converter built 51h x 3 x 2-1/8 alum inum mini-box portable version built cuVcEae 3ground lead short use 10 x 6 x 2 aluminum chassis bottom cover Physical parts placement fol lows schematic drawing inputs left outputs right oscillator section lower middle Sockets used transistors eliminate heat damage 4 METER AND 6 METER RECEIVNG CONVERTER FOR RC FREQUENCIES cascadeR F amplifiermixer RFC shield Cb IL3L4D QI SC6 70 CR1 _Cb. I8Cb 4 12v 1 r crystal controlled 33k local oscillator ll r~rmL1I output car O5mtradio SIA12 ant nna 121 Sib 25a CR3 i141145v 1 switch rotaryL switch tears 2 cryiols February 1982 37 About Author John R Lange has flying models since 1950s mostiy Free Flight Gas Old-Timer RC Assist Sailpianes systems engi neer microwave communications has worked TV tuner IF design John decided build RC frequency converters described after Dayton SAM Championships John tells us occasionally files seven-mile-square field converters handy see activity around since field large also help him work checking leakage communi cations equipment 70 MHz range would ordinarily have detec ted spectrum analyzer Presently member SOAR Lisle Aero RC Club John brings impressive technical skill bear RC interference problem BANDPASS CURVES 72MHz7 73MHz 535MHz 76 C4I2OpfC4l8Opf52 crystal osc freq shows curve PEAK TO PEAK RF DEMODULATOR TEST PROBE converter c output chassis ground 3 subminiature other coax oscilloscope mount 5 lug terminal strip soldering shortened transistor leads trimming about 3/16 fit socket better less likely jarred out Since transistors have different lead connections carefully ori ent leads after checking bottom views Plug transistors after wiring soldering finished make sure power plug aluminum shielding shown drawings isolates input output RF amplifier coils oscillator compart ment Its cut Reynolds sheet aluminum obtained hardware store installed after nearly other parts mounted Drill A-in holes shielding power injection output oscillator power output leads mixer Use sleeving shrink tubing long component leads Two reverse-connected 1N914 diodes wired across input terminals protec tion against excessive input signals No printed circuit boards necessary Editor PC boards available ad dress listed end article Wiring point-to-point between sockets minia ture terminal strips mounted 2-56 screws nuts lock washers bought several 5-lug miniature terminal strips trimmed off excess tugs sidecutters Component lead lengths should kept minimum especially 001 mf 470 pf 05 mf bypass capacitors C6 gate lead Q2 should short direct possible mixer output converter portable unit coupled ferrite rod tenna portable AM radio wrapping eight turns around antenna Shield interconnecting lead brald use short piece 2-conductor shielded wire connection helps minimize interfer ence AM broadcast stations near dial setting radio iron core tuned coils wound A-in diameter forms Miller 45004 forms will work other possibles A-in VHF coil forms James Mullen Cambridge Thermionic Cambion Coils old tube-type TV 45 MHz IF stage could stripped re wound coils RF chokes wound enamel- nylon-coated solid copper magnet wire can wind nice tight coils holding form both hands wire spool between knees Scrape sulation off tin wire ends before fastening RF choke 1-watt resistor File 1/16-in notch opposite edges 1-watt resistor help keep wire un raveling Coil start finish turns solder ed rings used Miller forms held down 1/8-in strips black plastic electrical tape wrapped around form lead Paint coils RF chokes GC Products Polystyrene Q Dope after wind ing Dont use model cement unless polystyrene-type Testors tube cement plastic models works fine 4-meter converter coil L5 its output link L6 used switched crystal frequencies found some weak transistors crystals wouldnt oscillate between highest crystal frequency 74640 MHz lower six frequencies between 7 1080 7 1960 MHz switched-in 22 pf capacitor low fre quencies corrected problem also opened switched between gate Q4 crystals rotary switch crystals connected common ground lug under mounting post nut switch common rotary switch contact tied directly gate Q4 Place switch close Q4 possible minimize stray capacity inductance speci fied second gang can used switch 22 pf capacitor align converter first get Q4 os cillate Turn radio connected J2 38 Model Aviation PARTS LIST 4-Meter 72 76 MI-lzJ6-Meter 53 535 MHz Li 21/2 turns No 28 wire over grounded endLi 3 turns No 28 wire over grounded end of L2 2 9 turns No 28 -in formL2 11 turns No 28 /4-in form L3 6 turns No 28L3 10 turns No 28 L4 512 turns No 28L4 9 turns No 28 L5 6 turns No 24L5 6 turns No 24 L6 1 turn No 24 over bypassed end L5L6 1 turn No 24 over bypassed end L5 L7 needed 8 turns No 24 wound over windings portable radios ferrite antenna RFC 25 turns No 28RFC 30 turns No 30 Cb 470 pf disk ceramic 25V moreCb 001 mf disk ceramic 25V C15pfC1l5pf C2lOpfC2lOpf C3 10 pfC3 10 pf C4 120 pfC4 330 pf C5 10 pfC5 20 pf C6 220 pf 47 pf car radioC6 330 pf 47 pf car radio Parts common both units Qi Q2 Q3 Q4 VHF UHF amplifier FET transistor Motorola 2N5485 2N5486 2N4416 Sylvania ECG-3 12 GE FET-3 CR1 CR2 1N914 silicon diodes CR3 20-volt 1-watt zener diode Y1 Y2 Series Resonance Fifth Overtone frequency crystal HC18/U holder see Frequency Crystal Selection Chart Fl 25-amp fuse clip holder Ji J2 J3 Receptacle Motorola-type broadcast antenna plug Radio Shack 274-712 H Smith 1207 J4 Four contact TRW cinch plug angle brackets P304-AB Cable socket TRW cinch S-304CCT Si Double pole double throw subminiature toggle switch S2 Double pole double throw subminiature toggle switch 2-section 2-pole 11-posItIon nonshorting ceramic rotary switch Centralab type 2513 Newark 22F416 Set seven positions Transistor sockets Radio Shack 276-548 Calectro-Cinch F2-984 5-lug miniature terminal strips Voitrex LTS-505C Newark 23N3990 Calectro F3-216 /4-in dia VHF iron core tuned coil forms Similar Miller 45004 20A000-4 Bell dustries Miller Div 19070 Reycs Ave Box 5285 Compton CA 90224 Milien 69048 69058 Millen Components 42A Pleasant St Stoneham MA 02180 Color-coded labels rotary swith positions Heathkit 390-919 Notes Chokes wound over 470K 1-watt Alien Bradley TRW Ohmite carbon composition resistor resistors /4-watt 10% coils RFC chokes wound solid enamel- soidereze-coated magnet wire Belden 8054 No 28 8055 No 30 8052 No 24 Fuse holder can optional builder 82-ohm 1W resistor reduced 82-ohm /4W resistor no fuse Turn up volume listen closely rushing noise speaker Now turn converter noise should increase Ad just iron core L5 until does Check crystal oscillates switched can whipping up peak-topeak demodulator test probe shown drawing Connect DC oscilloscope digital voltmeter Touch output link L6 chassis ground should obtain 2 volt better adjust L5 highest read ing can get just before oscillator quits Usually about 08 10 volt no oscillation obtained reduce coupling L6 L5 spreading open L6 sliding below bypassed end L5 still dont get oscillation remove iron core L5 slowly slide brass 10-3 2 8-32 screw end coil oscil lation occurs means L5 too large spread windings apart take off turn check iron core again Connect short whip antenna piece wire about foot long converter input Ji Turn RC transmitter leave antenna collapsed Turn AM radio converter tone buzz transmitter Back transmitter away retune radio loudest buzz Now move FREQUENCY CRYSTAL SELECTION CHART Portable Radio Unit RCV Crystal FrequencyFrequency 72080 MHz71080 MHz 72160 MHz71160 MHz 72240 MHz71240 MHz 72320 MHz71320MHz 72400MHz71400MHz 72960 MHz71960 MHz 75640 MHz74640 MHz 53100MHz 53200MHz 53300 MHz 53400 MHz CO53500 MHz transmitter farther away until buzz weak Adjust iron cores L2 L3 L4 loudest buzz L2 will tune broadly L3 L4 sharply Make sure both 72 MHz 75 MHz transmitter can heard sharper output indication can obtained using oscilloscope de modulator test probe connect probe output 12 drain Q3 may get better indication scope tem porarily removing L7 putting 150-ohm resistor its place 52100 MHz 52200 MHz 52300 MHz 52400 MHz 52500 MHz Tunable Car Radio Unit V Crystal AM Dial Frequency Reading 71400 MHz 680 KHz 760 KHz 840 KHz 920 KHz 1000KHz 1560 KHz 74640 MHz 1000 KHz 52000 MHz 1100 KHz 1200 KHz 1300 KHz 1400 KHz 1500 KHz AM Dial Reading 1000 KHz 1000 KHz 1000 KHz really want perfectionist can use sweep alignment setup shown VHF TV sweep marker signal generator will pick up 6-meter converter low end TV Channel 2 the 4-me ter converter high end Channel 4 low end Channel 5 Tune L2 maxi mize mid-part curve L3 L4 maximize curve amplitude po sition curves always tilted since no mixer peaking coil design Continued page 110 February 1982 39 Finished 6-meter 4-meter converters described text plugging car radio antenna converter connecting radio can tune listen RC frequencies two smaller units connection yourcar radio big unit middle contains small transistor radio set crystals forthe RC frequencies stand-alone operation Frequency Switching big unit contains small radio receiverright set receiving crystals attached rotary switch left Smaller converter 6-meter ham band needs internal shield Parts arrangement relatively simple PC boards available Insides 4-meter converter shows aluminum shielding around RF sections Two crystals allow tune across 72-75 MHz Text describes wind RF chokes will need wire connected test probe also described precise tuning LEADER IN SMALL AIRFOIL TECHNOLOGY MASTER AIRSCREW MBSW6 b3ISVV4MASTER IMPROVED THROUGH FOUR YEARS OF PRODUCTION THE G/F SERIES IS UNEQUALED FOR PERFORMANCE & DURABILITY AVAILABLE WORLDWIDE THROUGH 131 DISTRIBUTORS WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 lASTER AIIISCiIIW PRESENTS BALSA STRIPPER 495 AT YOUR DEALER PRECISION STRIP WOOD TO INS FROM BALSA SHEET ALSO FOR DRAFTING AND PHOTO MATS USES TYPE II BLADE SUPER TOOL T PRICE WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 CANTON MODEL PRODUCTS Presents Dip Stick FAST QUICK / EASY TO FINISH D540 55 SPAN 560 SQ IN WING LOADING 165-20 OZ 29-45 ENGINE 43 LENGTH 3 OR 4 CHANNEL PRICE 4995 ADD 4 SHIPPING CHARGE DS 60 641/2 SPAN 672 SQ IN WING LOADING 20-22 OZ 46-60 ENGINE 48 LENGTH 3 OR 4 CHANNEL PRICE 5995 EXTREMELYADD 6 SHIPPING RUGGED TRAINER CHARGE WITH SYMMETRICAL AIRFOIL FOR AEROBATIC FLYING HIGHLY PRE-FABRICATED KIT INCLUDES PRE-SHEETED BALSA FOAM WINGS PRE-BUILT JIG ASSEMBLED WOOD FUSELAGE PRE-SHAPE BALSA TAIL ASSEMBLY PRE-FORMED LANDING GEAR TAIL WHEEL AND AILERON WIRES INSTRUCTION SHEET WITH FULLY ILLUSTRATED ASSEMBLY DRAWINGS tow P ceo Cannot 0 SCOUR Doale s Black Widow/Baker Continued page 30 slowly fixed fuel pick-ups will starve engine slow roll Black Widow dream touch-andgoes Use wide pattern set up long final approach lowest throttle does want lose altitude final approach model assumes rather flat attitude can held right down ground Application full throttle results immediate return air Frequency Scanner/Lange Continued page 39 wish use RC transmitter check accuracy signal generator coupling L6 L5 tuning [5 should checked peak curve amplitude con sistent good oscillator starting have made some sensitivity tests several converters signal generator calibrated output could usually detect 01 RG58/u RG59AJ large wheels landings grass field have no-bounce greasers Singleengine performance excellent allows plenty time set up normal landing approach ailerons sufficient handle singleengine situations rudders very effec tive want use Despite its size small engines P-6 handles like trainer docile has no hidden faults waiting bite goes point Best does great deal realism microvolt signals three microvolt sig nals boomed through loud clear Consid ering RC receivers rated two three microvolts sensitivity thats quite ac ceptable best results obtained using a3- 5-ft extended whip antenna 4 6 meters usually can hear RC fliers transmitter two four miles field over flat terrain car engine turned off Sources Crystals JAN Crystals 2400 Crystal Dr PO Box I12v conte-jr scope vert hor ground generator scope converter aluminum copper sheet bench 110 Model Aviation BANDPASS ALIGNMENT WITH SWEEP GENERATOR AND SCOPE 00 VHF sweep marker gen RF sweep out out tO ORDER SEND BANK CHECK OR MONEY ORDER TO CANTON MODEL PRODUCTS PO BOX 6063 CANTON OHIO 44706 OR CALL 216 4541539 FOR IMMEDIATE COD SHIPMENT 06017 Ft Meyers FL 33908 PhoneRC Aerobatics/Van Putteattendance despitethe high quality ofthe contest 813 936-2397and outstanding traditional Saturday night International Crystal Manufacturing Co 20Continued page 41supper serve Well year 43 Pattern N Lee Oklahoma City OK 7310212 Sport Scale contestants delighted share boiled shrimp steamed crab supper Crescent City Radio Control Club members secret out other crashed airplanes cant repaired just well dont some give try certainly beats starting scratch way Ive often remarked annual New Orleans contest best kept secrets South because ofoccasional spirse PC Boards John R Lange 1700 N 37th Ave Stone Park IL 60165Ron Van Putie Ill Sleepy Oaks Rd Fr Walton Beach FL 32548 RC Giant Scale/Beckman Continued page 43 conversation Dave Scully Aero Compo sites 411 Townsend Place Dayton OH 45431 mentioned quarter-scale kit Hal Krierversion Great Lakes Special kit almost unknown dont really push said would send some information busy before got Ive busy havent done anything until now meantime saw Dave Toledo chance see plane fuselage comes kit fiberglass fuselage/foam wing kit too common Giant Scale fuselage has stringer detail molded cap strips wing foam before covering wind up realistic looking construction model designed prop drive setup originally has since changed Quadra significant improvement performance Daves picture-taking technique worth comment dont know other way vuure going get kind siew Giant Scale aircraft inside house Continued page 114 February 1982111 John Lange poseswith models frontot car isequipped listen current RC frequencies through car radio professional microwave technician John has made use RC frequency monitoring gear work well
Edition: Model Aviation - 1982/02
Page Numbers: 36, 37, 38, 39, 110, 111
IIeceiViq CoqVerters NC Frequeqcies youve done some electronics work can find way around schematic heres building pro ject useful device converter allows listen RC fre quency portable radio club should have U John R Lange WOULD YOU LIKE able monitor RC frequency before fly chase down interference check giltches Would like sure some elses transmit ter impound area car hasnt left get glitched would like sure interference got am ham radio operator fly RC 6 meters 53 MHz wanted check band before flying since 6 meters can fested ignition engine noise amateur FM repeaters other things devel oped -this receiving converter circuits ARRL Radio Amateurs VHF Manual Anyone has built Heathkit Ace kit ought able build Most parts can easily obtained local Radio AC Frequency Monitor can easily mounted under car dash Just swap plugs switch between RC frequencies broadcast stations 4 METER AND 6 METER RC FREQUENCY CONVERTER IN 5 I/4x3Mx2 I/8 ALUMINUM BOX WITH UNDER DASH MOUNTING BRACKETS RADIO eOe eWe eOe ANTENNA 0 4 meter shown 6 meter has no 72-75 switch 2 0 eOe INPUT scale inches OL........1 3 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER PARTS LAYOUT IN 5 1/4 x 3x2 I/B ALUMINUM BOX BUDD CU 210GB CU-3006A RADIO SHACK 270-238 LMB 780 ALECTRO H4T741l/2x5/8cutout shield socket coil leads away chassis go gates drains leads closest chassis go terminal strip ground lugs bypass capacitors Cb Shack store receiving crystals can mallordered JAN Crystals International Crystals Addresses appear end article receiving converter can built either two ways version small mini box mounted under dash car uses cars whip antenna power fuse block Its connected car AM radio radio tuner selects chan nel want listen puts out car speaker listen radio simply turn off converter second version portable con tains its own pocket-size AM receiver 1 C U Cq o 10 0 0 U 0 0 S2 omitted 6 meter Cape inside nverters crystal iscover area rO between gate ground lug oNEINcNSCALE second version has seven-position rotary switch connected seven crystals can tune seven RC frequencies 4-me ter RC band way tune TV set first converter 6 meters hooked up car radio has two-FET-transistor cascode RF amplifier stage FET transistor mixer 52 MHz crystal-controlled FET transistor oscillator use 2-ft coaxial extension lead Moto rola male plugs connect car radio cord Part No 12-1314 Radio Shack listen RC frequencies unplug car antenna lead back antenna jack J3 plug front input Ji turn 36 Model Aviation eR @eQe e ee0 ONeBrW7208 680 01087216 760 0408 7224 840 ______Or-SO 7240 VoSO 7232 920 OFF727500-08 7296 1560 shielduse bottom hole 191of ground lugInsulat cbDL33Output RFC Cb4 RFC LI stand end wisleeveshield use sleevin 4-40 check clearanceY2 antennato fuse center pin tobngsleeving1-I25to shield use bottom hole gnd lugi-I45v 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER INTERNAL SHIELDS round off use 5052-H 32 sheet aluminum corners 0 0 o make bends vise dashed lines holes 3/32 diameter 10 A-I converter tune car radio tween 1100 1500 AM dial gives 531 MHz 1100 535 1500 pre-set two radio push-buttons correct spot two RC frequencies use just hit buttonjust like dialing AM station converter setup 4-me ter band 72 76 MHz works same way 4-meter converter can pick up sev en RC frequencies two receiving crystals Since first six frequencies tween 72080 72960 MHz less MHz apart 714 MHz crystal con verter local oscillator will aliow tune ali between 540 1600 radio diaL seventh frequency 75640 picked up switching 74640 crystal appears 1000 dial enough range either side bands receive adjacent interference sources get new frequencies hope tune weli portable converter has small under$10 Radio Shack AM pocket portable radio catalog number 12-171 12-172 tuned 1000 dial seven re ceiving crystals converter 1 MHz low corresponding RC frequency mounted poles rotary switch nine-volt battery series two AA pencells gives 12 volts needed convert er radio course has its own battery might consider building circuit aluminum box chassis case small car radio whip antenna instead pocket portable radio would allow power whole works 12-volt Gel Cell Ni-Cad pack also eliminates AM broadcasts pocket portable radio alignment G C6 I5ch pf__ --12v PORTABLERFC v--Gb OUTPUT FOR POCKET RECEIVER FUSE HOLDER MOUNTING DETAIL 25A fuse to~yJ424 scaleinchesIlockwt~T7i&I 0I23 Um~hiU LFLJ4-40x3/4 BOTTOM VIEW OF TRANSISTORS SG D DQ SQgroundD casecase round 2N5485 2N5486 ECG -312 Ddrain Ssource 2N4416 Ggate will occasionally pick up stations close 1000 dial Construction under-dash version converter built 51h x 3 x 2-1/8 alum inum mini-box portable version built cuVcEae 3ground lead short use 10 x 6 x 2 aluminum chassis bottom cover Physical parts placement fol lows schematic drawing inputs left outputs right oscillator section lower middle Sockets used transistors eliminate heat damage 4 METER AND 6 METER RECEIVNG CONVERTER FOR RC FREQUENCIES cascadeR F amplifiermixer RFC shield Cb IL3L4D QI SC6 70 CR1 _Cb. I8Cb 4 12v 1 r crystal controlled 33k local oscillator ll r~rmL1I output car O5mtradio SIA12 ant nna 121 Sib 25a CR3 i141145v 1 switch rotaryL switch tears 2 cryiols February 1982 37 About Author John R Lange has flying models since 1950s mostiy Free Flight Gas Old-Timer RC Assist Sailpianes systems engi neer microwave communications has worked TV tuner IF design John decided build RC frequency converters described after Dayton SAM Championships John tells us occasionally files seven-mile-square field converters handy see activity around since field large also help him work checking leakage communi cations equipment 70 MHz range would ordinarily have detec ted spectrum analyzer Presently member SOAR Lisle Aero RC Club John brings impressive technical skill bear RC interference problem BANDPASS CURVES 72MHz7 73MHz 535MHz 76 C4I2OpfC4l8Opf52 crystal osc freq shows curve PEAK TO PEAK RF DEMODULATOR TEST PROBE converter c output chassis ground 3 subminiature other coax oscilloscope mount 5 lug terminal strip soldering shortened transistor leads trimming about 3/16 fit socket better less likely jarred out Since transistors have different lead connections carefully ori ent leads after checking bottom views Plug transistors after wiring soldering finished make sure power plug aluminum shielding shown drawings isolates input output RF amplifier coils oscillator compart ment Its cut Reynolds sheet aluminum obtained hardware store installed after nearly other parts mounted Drill A-in holes shielding power injection output oscillator power output leads mixer Use sleeving shrink tubing long component leads Two reverse-connected 1N914 diodes wired across input terminals protec tion against excessive input signals No printed circuit boards necessary Editor PC boards available ad dress listed end article Wiring point-to-point between sockets minia ture terminal strips mounted 2-56 screws nuts lock washers bought several 5-lug miniature terminal strips trimmed off excess tugs sidecutters Component lead lengths should kept minimum especially 001 mf 470 pf 05 mf bypass capacitors C6 gate lead Q2 should short direct possible mixer output converter portable unit coupled ferrite rod tenna portable AM radio wrapping eight turns around antenna Shield interconnecting lead brald use short piece 2-conductor shielded wire connection helps minimize interfer ence AM broadcast stations near dial setting radio iron core tuned coils wound A-in diameter forms Miller 45004 forms will work other possibles A-in VHF coil forms James Mullen Cambridge Thermionic Cambion Coils old tube-type TV 45 MHz IF stage could stripped re wound coils RF chokes wound enamel- nylon-coated solid copper magnet wire can wind nice tight coils holding form both hands wire spool between knees Scrape sulation off tin wire ends before fastening RF choke 1-watt resistor File 1/16-in notch opposite edges 1-watt resistor help keep wire un raveling Coil start finish turns solder ed rings used Miller forms held down 1/8-in strips black plastic electrical tape wrapped around form lead Paint coils RF chokes GC Products Polystyrene Q Dope after wind ing Dont use model cement unless polystyrene-type Testors tube cement plastic models works fine 4-meter converter coil L5 its output link L6 used switched crystal frequencies found some weak transistors crystals wouldnt oscillate between highest crystal frequency 74640 MHz lower six frequencies between 7 1080 7 1960 MHz switched-in 22 pf capacitor low fre quencies corrected problem also opened switched between gate Q4 crystals rotary switch crystals connected common ground lug under mounting post nut switch common rotary switch contact tied directly gate Q4 Place switch close Q4 possible minimize stray capacity inductance speci fied second gang can used switch 22 pf capacitor align converter first get Q4 os cillate Turn radio connected J2 38 Model Aviation PARTS LIST 4-Meter 72 76 MI-lzJ6-Meter 53 535 MHz Li 21/2 turns No 28 wire over grounded endLi 3 turns No 28 wire over grounded end of L2 2 9 turns No 28 -in formL2 11 turns No 28 /4-in form L3 6 turns No 28L3 10 turns No 28 L4 512 turns No 28L4 9 turns No 28 L5 6 turns No 24L5 6 turns No 24 L6 1 turn No 24 over bypassed end L5L6 1 turn No 24 over bypassed end L5 L7 needed 8 turns No 24 wound over windings portable radios ferrite antenna RFC 25 turns No 28RFC 30 turns No 30 Cb 470 pf disk ceramic 25V moreCb 001 mf disk ceramic 25V C15pfC1l5pf C2lOpfC2lOpf C3 10 pfC3 10 pf C4 120 pfC4 330 pf C5 10 pfC5 20 pf C6 220 pf 47 pf car radioC6 330 pf 47 pf car radio Parts common both units Qi Q2 Q3 Q4 VHF UHF amplifier FET transistor Motorola 2N5485 2N5486 2N4416 Sylvania ECG-3 12 GE FET-3 CR1 CR2 1N914 silicon diodes CR3 20-volt 1-watt zener diode Y1 Y2 Series Resonance Fifth Overtone frequency crystal HC18/U holder see Frequency Crystal Selection Chart Fl 25-amp fuse clip holder Ji J2 J3 Receptacle Motorola-type broadcast antenna plug Radio Shack 274-712 H Smith 1207 J4 Four contact TRW cinch plug angle brackets P304-AB Cable socket TRW cinch S-304CCT Si Double pole double throw subminiature toggle switch S2 Double pole double throw subminiature toggle switch 2-section 2-pole 11-posItIon nonshorting ceramic rotary switch Centralab type 2513 Newark 22F416 Set seven positions Transistor sockets Radio Shack 276-548 Calectro-Cinch F2-984 5-lug miniature terminal strips Voitrex LTS-505C Newark 23N3990 Calectro F3-216 /4-in dia VHF iron core tuned coil forms Similar Miller 45004 20A000-4 Bell dustries Miller Div 19070 Reycs Ave Box 5285 Compton CA 90224 Milien 69048 69058 Millen Components 42A Pleasant St Stoneham MA 02180 Color-coded labels rotary swith positions Heathkit 390-919 Notes Chokes wound over 470K 1-watt Alien Bradley TRW Ohmite carbon composition resistor resistors /4-watt 10% coils RFC chokes wound solid enamel- soidereze-coated magnet wire Belden 8054 No 28 8055 No 30 8052 No 24 Fuse holder can optional builder 82-ohm 1W resistor reduced 82-ohm /4W resistor no fuse Turn up volume listen closely rushing noise speaker Now turn converter noise should increase Ad just iron core L5 until does Check crystal oscillates switched can whipping up peak-topeak demodulator test probe shown drawing Connect DC oscilloscope digital voltmeter Touch output link L6 chassis ground should obtain 2 volt better adjust L5 highest read ing can get just before oscillator quits Usually about 08 10 volt no oscillation obtained reduce coupling L6 L5 spreading open L6 sliding below bypassed end L5 still dont get oscillation remove iron core L5 slowly slide brass 10-3 2 8-32 screw end coil oscil lation occurs means L5 too large spread windings apart take off turn check iron core again Connect short whip antenna piece wire about foot long converter input Ji Turn RC transmitter leave antenna collapsed Turn AM radio converter tone buzz transmitter Back transmitter away retune radio loudest buzz Now move FREQUENCY CRYSTAL SELECTION CHART Portable Radio Unit RCV Crystal FrequencyFrequency 72080 MHz71080 MHz 72160 MHz71160 MHz 72240 MHz71240 MHz 72320 MHz71320MHz 72400MHz71400MHz 72960 MHz71960 MHz 75640 MHz74640 MHz 53100MHz 53200MHz 53300 MHz 53400 MHz CO53500 MHz transmitter farther away until buzz weak Adjust iron cores L2 L3 L4 loudest buzz L2 will tune broadly L3 L4 sharply Make sure both 72 MHz 75 MHz transmitter can heard sharper output indication can obtained using oscilloscope de modulator test probe connect probe output 12 drain Q3 may get better indication scope tem porarily removing L7 putting 150-ohm resistor its place 52100 MHz 52200 MHz 52300 MHz 52400 MHz 52500 MHz Tunable Car Radio Unit V Crystal AM Dial Frequency Reading 71400 MHz 680 KHz 760 KHz 840 KHz 920 KHz 1000KHz 1560 KHz 74640 MHz 1000 KHz 52000 MHz 1100 KHz 1200 KHz 1300 KHz 1400 KHz 1500 KHz AM Dial Reading 1000 KHz 1000 KHz 1000 KHz really want perfectionist can use sweep alignment setup shown VHF TV sweep marker signal generator will pick up 6-meter converter low end TV Channel 2 the 4-me ter converter high end Channel 4 low end Channel 5 Tune L2 maxi mize mid-part curve L3 L4 maximize curve amplitude po sition curves always tilted since no mixer peaking coil design Continued page 110 February 1982 39 Finished 6-meter 4-meter converters described text plugging car radio antenna converter connecting radio can tune listen RC frequencies two smaller units connection yourcar radio big unit middle contains small transistor radio set crystals forthe RC frequencies stand-alone operation Frequency Switching big unit contains small radio receiverright set receiving crystals attached rotary switch left Smaller converter 6-meter ham band needs internal shield Parts arrangement relatively simple PC boards available Insides 4-meter converter shows aluminum shielding around RF sections Two crystals allow tune across 72-75 MHz Text describes wind RF chokes will need wire connected test probe also described precise tuning LEADER IN SMALL AIRFOIL TECHNOLOGY MASTER AIRSCREW MBSW6 b3ISVV4MASTER IMPROVED THROUGH FOUR YEARS OF PRODUCTION THE G/F SERIES IS UNEQUALED FOR PERFORMANCE & DURABILITY AVAILABLE WORLDWIDE THROUGH 131 DISTRIBUTORS WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 lASTER AIIISCiIIW PRESENTS BALSA STRIPPER 495 AT YOUR DEALER PRECISION STRIP WOOD TO INS FROM BALSA SHEET ALSO FOR DRAFTING AND PHOTO MATS USES TYPE II BLADE SUPER TOOL T PRICE WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 CANTON MODEL PRODUCTS Presents Dip Stick FAST QUICK / EASY TO FINISH D540 55 SPAN 560 SQ IN WING LOADING 165-20 OZ 29-45 ENGINE 43 LENGTH 3 OR 4 CHANNEL PRICE 4995 ADD 4 SHIPPING CHARGE DS 60 641/2 SPAN 672 SQ IN WING LOADING 20-22 OZ 46-60 ENGINE 48 LENGTH 3 OR 4 CHANNEL PRICE 5995 EXTREMELYADD 6 SHIPPING RUGGED TRAINER CHARGE WITH SYMMETRICAL AIRFOIL FOR AEROBATIC FLYING HIGHLY PRE-FABRICATED KIT INCLUDES PRE-SHEETED BALSA FOAM WINGS PRE-BUILT JIG ASSEMBLED WOOD FUSELAGE PRE-SHAPE BALSA TAIL ASSEMBLY PRE-FORMED LANDING GEAR TAIL WHEEL AND AILERON WIRES INSTRUCTION SHEET WITH FULLY ILLUSTRATED ASSEMBLY DRAWINGS tow P ceo Cannot 0 SCOUR Doale s Black Widow/Baker Continued page 30 slowly fixed fuel pick-ups will starve engine slow roll Black Widow dream touch-andgoes Use wide pattern set up long final approach lowest throttle does want lose altitude final approach model assumes rather flat attitude can held right down ground Application full throttle results immediate return air Frequency Scanner/Lange Continued page 39 wish use RC transmitter check accuracy signal generator coupling L6 L5 tuning [5 should checked peak curve amplitude con sistent good oscillator starting have made some sensitivity tests several converters signal generator calibrated output could usually detect 01 RG58/u RG59AJ large wheels landings grass field have no-bounce greasers Singleengine performance excellent allows plenty time set up normal landing approach ailerons sufficient handle singleengine situations rudders very effec tive want use Despite its size small engines P-6 handles like trainer docile has no hidden faults waiting bite goes point Best does great deal realism microvolt signals three microvolt sig nals boomed through loud clear Consid ering RC receivers rated two three microvolts sensitivity thats quite ac ceptable best results obtained using a3- 5-ft extended whip antenna 4 6 meters usually can hear RC fliers transmitter two four miles field over flat terrain car engine turned off Sources Crystals JAN Crystals 2400 Crystal Dr PO Box I12v conte-jr scope vert hor ground generator scope converter aluminum copper sheet bench 110 Model Aviation BANDPASS ALIGNMENT WITH SWEEP GENERATOR AND SCOPE 00 VHF sweep marker gen RF sweep out out tO ORDER SEND BANK CHECK OR MONEY ORDER TO CANTON MODEL PRODUCTS PO BOX 6063 CANTON OHIO 44706 OR CALL 216 4541539 FOR IMMEDIATE COD SHIPMENT 06017 Ft Meyers FL 33908 PhoneRC Aerobatics/Van Putteattendance despitethe high quality ofthe contest 813 936-2397and outstanding traditional Saturday night International Crystal Manufacturing Co 20Continued page 41supper serve Well year 43 Pattern N Lee Oklahoma City OK 7310212 Sport Scale contestants delighted share boiled shrimp steamed crab supper Crescent City Radio Control Club members secret out other crashed airplanes cant repaired just well dont some give try certainly beats starting scratch way Ive often remarked annual New Orleans contest best kept secrets South because ofoccasional spirse PC Boards John R Lange 1700 N 37th Ave Stone Park IL 60165Ron Van Putie Ill Sleepy Oaks Rd Fr Walton Beach FL 32548 RC Giant Scale/Beckman Continued page 43 conversation Dave Scully Aero Compo sites 411 Townsend Place Dayton OH 45431 mentioned quarter-scale kit Hal Krierversion Great Lakes Special kit almost unknown dont really push said would send some information busy before got Ive busy havent done anything until now meantime saw Dave Toledo chance see plane fuselage comes kit fiberglass fuselage/foam wing kit too common Giant Scale fuselage has stringer detail molded cap strips wing foam before covering wind up realistic looking construction model designed prop drive setup originally has since changed Quadra significant improvement performance Daves picture-taking technique worth comment dont know other way vuure going get kind siew Giant Scale aircraft inside house Continued page 114 February 1982111 John Lange poseswith models frontot car isequipped listen current RC frequencies through car radio professional microwave technician John has made use RC frequency monitoring gear work well
Edition: Model Aviation - 1982/02
Page Numbers: 36, 37, 38, 39, 110, 111
IIeceiViq CoqVerters NC Frequeqcies youve done some electronics work can find way around schematic heres building pro ject useful device converter allows listen RC fre quency portable radio club should have U John R Lange WOULD YOU LIKE able monitor RC frequency before fly chase down interference check giltches Would like sure some elses transmit ter impound area car hasnt left get glitched would like sure interference got am ham radio operator fly RC 6 meters 53 MHz wanted check band before flying since 6 meters can fested ignition engine noise amateur FM repeaters other things devel oped -this receiving converter circuits ARRL Radio Amateurs VHF Manual Anyone has built Heathkit Ace kit ought able build Most parts can easily obtained local Radio AC Frequency Monitor can easily mounted under car dash Just swap plugs switch between RC frequencies broadcast stations 4 METER AND 6 METER RC FREQUENCY CONVERTER IN 5 I/4x3Mx2 I/8 ALUMINUM BOX WITH UNDER DASH MOUNTING BRACKETS RADIO eOe eWe eOe ANTENNA 0 4 meter shown 6 meter has no 72-75 switch 2 0 eOe INPUT scale inches OL........1 3 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER PARTS LAYOUT IN 5 1/4 x 3x2 I/B ALUMINUM BOX BUDD CU 210GB CU-3006A RADIO SHACK 270-238 LMB 780 ALECTRO H4T741l/2x5/8cutout shield socket coil leads away chassis go gates drains leads closest chassis go terminal strip ground lugs bypass capacitors Cb Shack store receiving crystals can mallordered JAN Crystals International Crystals Addresses appear end article receiving converter can built either two ways version small mini box mounted under dash car uses cars whip antenna power fuse block Its connected car AM radio radio tuner selects chan nel want listen puts out car speaker listen radio simply turn off converter second version portable con tains its own pocket-size AM receiver 1 C U Cq o 10 0 0 U 0 0 S2 omitted 6 meter Cape inside nverters crystal iscover area rO between gate ground lug oNEINcNSCALE second version has seven-position rotary switch connected seven crystals can tune seven RC frequencies 4-me ter RC band way tune TV set first converter 6 meters hooked up car radio has two-FET-transistor cascode RF amplifier stage FET transistor mixer 52 MHz crystal-controlled FET transistor oscillator use 2-ft coaxial extension lead Moto rola male plugs connect car radio cord Part No 12-1314 Radio Shack listen RC frequencies unplug car antenna lead back antenna jack J3 plug front input Ji turn 36 Model Aviation eR @eQe e ee0 ONeBrW7208 680 01087216 760 0408 7224 840 ______Or-SO 7240 VoSO 7232 920 OFF727500-08 7296 1560 shielduse bottom hole 191of ground lugInsulat cbDL33Output RFC Cb4 RFC LI stand end wisleeveshield use sleevin 4-40 check clearanceY2 antennato fuse center pin tobngsleeving1-I25to shield use bottom hole gnd lugi-I45v 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER INTERNAL SHIELDS round off use 5052-H 32 sheet aluminum corners 0 0 o make bends vise dashed lines holes 3/32 diameter 10 A-I converter tune car radio tween 1100 1500 AM dial gives 531 MHz 1100 535 1500 pre-set two radio push-buttons correct spot two RC frequencies use just hit buttonjust like dialing AM station converter setup 4-me ter band 72 76 MHz works same way 4-meter converter can pick up sev en RC frequencies two receiving crystals Since first six frequencies tween 72080 72960 MHz less MHz apart 714 MHz crystal con verter local oscillator will aliow tune ali between 540 1600 radio diaL seventh frequency 75640 picked up switching 74640 crystal appears 1000 dial enough range either side bands receive adjacent interference sources get new frequencies hope tune weli portable converter has small under$10 Radio Shack AM pocket portable radio catalog number 12-171 12-172 tuned 1000 dial seven re ceiving crystals converter 1 MHz low corresponding RC frequency mounted poles rotary switch nine-volt battery series two AA pencells gives 12 volts needed convert er radio course has its own battery might consider building circuit aluminum box chassis case small car radio whip antenna instead pocket portable radio would allow power whole works 12-volt Gel Cell Ni-Cad pack also eliminates AM broadcasts pocket portable radio alignment G C6 I5ch pf__ --12v PORTABLERFC v--Gb OUTPUT FOR POCKET RECEIVER FUSE HOLDER MOUNTING DETAIL 25A fuse to~yJ424 scaleinchesIlockwt~T7i&I 0I23 Um~hiU LFLJ4-40x3/4 BOTTOM VIEW OF TRANSISTORS SG D DQ SQgroundD casecase round 2N5485 2N5486 ECG -312 Ddrain Ssource 2N4416 Ggate will occasionally pick up stations close 1000 dial Construction under-dash version converter built 51h x 3 x 2-1/8 alum inum mini-box portable version built cuVcEae 3ground lead short use 10 x 6 x 2 aluminum chassis bottom cover Physical parts placement fol lows schematic drawing inputs left outputs right oscillator section lower middle Sockets used transistors eliminate heat damage 4 METER AND 6 METER RECEIVNG CONVERTER FOR RC FREQUENCIES cascadeR F amplifiermixer RFC shield Cb IL3L4D QI SC6 70 CR1 _Cb. I8Cb 4 12v 1 r crystal controlled 33k local oscillator ll r~rmL1I output car O5mtradio SIA12 ant nna 121 Sib 25a CR3 i141145v 1 switch rotaryL switch tears 2 cryiols February 1982 37 About Author John R Lange has flying models since 1950s mostiy Free Flight Gas Old-Timer RC Assist Sailpianes systems engi neer microwave communications has worked TV tuner IF design John decided build RC frequency converters described after Dayton SAM Championships John tells us occasionally files seven-mile-square field converters handy see activity around since field large also help him work checking leakage communi cations equipment 70 MHz range would ordinarily have detec ted spectrum analyzer Presently member SOAR Lisle Aero RC Club John brings impressive technical skill bear RC interference problem BANDPASS CURVES 72MHz7 73MHz 535MHz 76 C4I2OpfC4l8Opf52 crystal osc freq shows curve PEAK TO PEAK RF DEMODULATOR TEST PROBE converter c output chassis ground 3 subminiature other coax oscilloscope mount 5 lug terminal strip soldering shortened transistor leads trimming about 3/16 fit socket better less likely jarred out Since transistors have different lead connections carefully ori ent leads after checking bottom views Plug transistors after wiring soldering finished make sure power plug aluminum shielding shown drawings isolates input output RF amplifier coils oscillator compart ment Its cut Reynolds sheet aluminum obtained hardware store installed after nearly other parts mounted Drill A-in holes shielding power injection output oscillator power output leads mixer Use sleeving shrink tubing long component leads Two reverse-connected 1N914 diodes wired across input terminals protec tion against excessive input signals No printed circuit boards necessary Editor PC boards available ad dress listed end article Wiring point-to-point between sockets minia ture terminal strips mounted 2-56 screws nuts lock washers bought several 5-lug miniature terminal strips trimmed off excess tugs sidecutters Component lead lengths should kept minimum especially 001 mf 470 pf 05 mf bypass capacitors C6 gate lead Q2 should short direct possible mixer output converter portable unit coupled ferrite rod tenna portable AM radio wrapping eight turns around antenna Shield interconnecting lead brald use short piece 2-conductor shielded wire connection helps minimize interfer ence AM broadcast stations near dial setting radio iron core tuned coils wound A-in diameter forms Miller 45004 forms will work other possibles A-in VHF coil forms James Mullen Cambridge Thermionic Cambion Coils old tube-type TV 45 MHz IF stage could stripped re wound coils RF chokes wound enamel- nylon-coated solid copper magnet wire can wind nice tight coils holding form both hands wire spool between knees Scrape sulation off tin wire ends before fastening RF choke 1-watt resistor File 1/16-in notch opposite edges 1-watt resistor help keep wire un raveling Coil start finish turns solder ed rings used Miller forms held down 1/8-in strips black plastic electrical tape wrapped around form lead Paint coils RF chokes GC Products Polystyrene Q Dope after wind ing Dont use model cement unless polystyrene-type Testors tube cement plastic models works fine 4-meter converter coil L5 its output link L6 used switched crystal frequencies found some weak transistors crystals wouldnt oscillate between highest crystal frequency 74640 MHz lower six frequencies between 7 1080 7 1960 MHz switched-in 22 pf capacitor low fre quencies corrected problem also opened switched between gate Q4 crystals rotary switch crystals connected common ground lug under mounting post nut switch common rotary switch contact tied directly gate Q4 Place switch close Q4 possible minimize stray capacity inductance speci fied second gang can used switch 22 pf capacitor align converter first get Q4 os cillate Turn radio connected J2 38 Model Aviation PARTS LIST 4-Meter 72 76 MI-lzJ6-Meter 53 535 MHz Li 21/2 turns No 28 wire over grounded endLi 3 turns No 28 wire over grounded end of L2 2 9 turns No 28 -in formL2 11 turns No 28 /4-in form L3 6 turns No 28L3 10 turns No 28 L4 512 turns No 28L4 9 turns No 28 L5 6 turns No 24L5 6 turns No 24 L6 1 turn No 24 over bypassed end L5L6 1 turn No 24 over bypassed end L5 L7 needed 8 turns No 24 wound over windings portable radios ferrite antenna RFC 25 turns No 28RFC 30 turns No 30 Cb 470 pf disk ceramic 25V moreCb 001 mf disk ceramic 25V C15pfC1l5pf C2lOpfC2lOpf C3 10 pfC3 10 pf C4 120 pfC4 330 pf C5 10 pfC5 20 pf C6 220 pf 47 pf car radioC6 330 pf 47 pf car radio Parts common both units Qi Q2 Q3 Q4 VHF UHF amplifier FET transistor Motorola 2N5485 2N5486 2N4416 Sylvania ECG-3 12 GE FET-3 CR1 CR2 1N914 silicon diodes CR3 20-volt 1-watt zener diode Y1 Y2 Series Resonance Fifth Overtone frequency crystal HC18/U holder see Frequency Crystal Selection Chart Fl 25-amp fuse clip holder Ji J2 J3 Receptacle Motorola-type broadcast antenna plug Radio Shack 274-712 H Smith 1207 J4 Four contact TRW cinch plug angle brackets P304-AB Cable socket TRW cinch S-304CCT Si Double pole double throw subminiature toggle switch S2 Double pole double throw subminiature toggle switch 2-section 2-pole 11-posItIon nonshorting ceramic rotary switch Centralab type 2513 Newark 22F416 Set seven positions Transistor sockets Radio Shack 276-548 Calectro-Cinch F2-984 5-lug miniature terminal strips Voitrex LTS-505C Newark 23N3990 Calectro F3-216 /4-in dia VHF iron core tuned coil forms Similar Miller 45004 20A000-4 Bell dustries Miller Div 19070 Reycs Ave Box 5285 Compton CA 90224 Milien 69048 69058 Millen Components 42A Pleasant St Stoneham MA 02180 Color-coded labels rotary swith positions Heathkit 390-919 Notes Chokes wound over 470K 1-watt Alien Bradley TRW Ohmite carbon composition resistor resistors /4-watt 10% coils RFC chokes wound solid enamel- soidereze-coated magnet wire Belden 8054 No 28 8055 No 30 8052 No 24 Fuse holder can optional builder 82-ohm 1W resistor reduced 82-ohm /4W resistor no fuse Turn up volume listen closely rushing noise speaker Now turn converter noise should increase Ad just iron core L5 until does Check crystal oscillates switched can whipping up peak-topeak demodulator test probe shown drawing Connect DC oscilloscope digital voltmeter Touch output link L6 chassis ground should obtain 2 volt better adjust L5 highest read ing can get just before oscillator quits Usually about 08 10 volt no oscillation obtained reduce coupling L6 L5 spreading open L6 sliding below bypassed end L5 still dont get oscillation remove iron core L5 slowly slide brass 10-3 2 8-32 screw end coil oscil lation occurs means L5 too large spread windings apart take off turn check iron core again Connect short whip antenna piece wire about foot long converter input Ji Turn RC transmitter leave antenna collapsed Turn AM radio converter tone buzz transmitter Back transmitter away retune radio loudest buzz Now move FREQUENCY CRYSTAL SELECTION CHART Portable Radio Unit RCV Crystal FrequencyFrequency 72080 MHz71080 MHz 72160 MHz71160 MHz 72240 MHz71240 MHz 72320 MHz71320MHz 72400MHz71400MHz 72960 MHz71960 MHz 75640 MHz74640 MHz 53100MHz 53200MHz 53300 MHz 53400 MHz CO53500 MHz transmitter farther away until buzz weak Adjust iron cores L2 L3 L4 loudest buzz L2 will tune broadly L3 L4 sharply Make sure both 72 MHz 75 MHz transmitter can heard sharper output indication can obtained using oscilloscope de modulator test probe connect probe output 12 drain Q3 may get better indication scope tem porarily removing L7 putting 150-ohm resistor its place 52100 MHz 52200 MHz 52300 MHz 52400 MHz 52500 MHz Tunable Car Radio Unit V Crystal AM Dial Frequency Reading 71400 MHz 680 KHz 760 KHz 840 KHz 920 KHz 1000KHz 1560 KHz 74640 MHz 1000 KHz 52000 MHz 1100 KHz 1200 KHz 1300 KHz 1400 KHz 1500 KHz AM Dial Reading 1000 KHz 1000 KHz 1000 KHz really want perfectionist can use sweep alignment setup shown VHF TV sweep marker signal generator will pick up 6-meter converter low end TV Channel 2 the 4-me ter converter high end Channel 4 low end Channel 5 Tune L2 maxi mize mid-part curve L3 L4 maximize curve amplitude po sition curves always tilted since no mixer peaking coil design Continued page 110 February 1982 39 Finished 6-meter 4-meter converters described text plugging car radio antenna converter connecting radio can tune listen RC frequencies two smaller units connection yourcar radio big unit middle contains small transistor radio set crystals forthe RC frequencies stand-alone operation Frequency Switching big unit contains small radio receiverright set receiving crystals attached rotary switch left Smaller converter 6-meter ham band needs internal shield Parts arrangement relatively simple PC boards available Insides 4-meter converter shows aluminum shielding around RF sections Two crystals allow tune across 72-75 MHz Text describes wind RF chokes will need wire connected test probe also described precise tuning LEADER IN SMALL AIRFOIL TECHNOLOGY MASTER AIRSCREW MBSW6 b3ISVV4MASTER IMPROVED THROUGH FOUR YEARS OF PRODUCTION THE G/F SERIES IS UNEQUALED FOR PERFORMANCE & DURABILITY AVAILABLE WORLDWIDE THROUGH 131 DISTRIBUTORS WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 lASTER AIIISCiIIW PRESENTS BALSA STRIPPER 495 AT YOUR DEALER PRECISION STRIP WOOD TO INS FROM BALSA SHEET ALSO FOR DRAFTING AND PHOTO MATS USES TYPE II BLADE SUPER TOOL T PRICE WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 CANTON MODEL PRODUCTS Presents Dip Stick FAST QUICK / EASY TO FINISH D540 55 SPAN 560 SQ IN WING LOADING 165-20 OZ 29-45 ENGINE 43 LENGTH 3 OR 4 CHANNEL PRICE 4995 ADD 4 SHIPPING CHARGE DS 60 641/2 SPAN 672 SQ IN WING LOADING 20-22 OZ 46-60 ENGINE 48 LENGTH 3 OR 4 CHANNEL PRICE 5995 EXTREMELYADD 6 SHIPPING RUGGED TRAINER CHARGE WITH SYMMETRICAL AIRFOIL FOR AEROBATIC FLYING HIGHLY PRE-FABRICATED KIT INCLUDES PRE-SHEETED BALSA FOAM WINGS PRE-BUILT JIG ASSEMBLED WOOD FUSELAGE PRE-SHAPE BALSA TAIL ASSEMBLY PRE-FORMED LANDING GEAR TAIL WHEEL AND AILERON WIRES INSTRUCTION SHEET WITH FULLY ILLUSTRATED ASSEMBLY DRAWINGS tow P ceo Cannot 0 SCOUR Doale s Black Widow/Baker Continued page 30 slowly fixed fuel pick-ups will starve engine slow roll Black Widow dream touch-andgoes Use wide pattern set up long final approach lowest throttle does want lose altitude final approach model assumes rather flat attitude can held right down ground Application full throttle results immediate return air Frequency Scanner/Lange Continued page 39 wish use RC transmitter check accuracy signal generator coupling L6 L5 tuning [5 should checked peak curve amplitude con sistent good oscillator starting have made some sensitivity tests several converters signal generator calibrated output could usually detect 01 RG58/u RG59AJ large wheels landings grass field have no-bounce greasers Singleengine performance excellent allows plenty time set up normal landing approach ailerons sufficient handle singleengine situations rudders very effec tive want use Despite its size small engines P-6 handles like trainer docile has no hidden faults waiting bite goes point Best does great deal realism microvolt signals three microvolt sig nals boomed through loud clear Consid ering RC receivers rated two three microvolts sensitivity thats quite ac ceptable best results obtained using a3- 5-ft extended whip antenna 4 6 meters usually can hear RC fliers transmitter two four miles field over flat terrain car engine turned off Sources Crystals JAN Crystals 2400 Crystal Dr PO Box I12v conte-jr scope vert hor ground generator scope converter aluminum copper sheet bench 110 Model Aviation BANDPASS ALIGNMENT WITH SWEEP GENERATOR AND SCOPE 00 VHF sweep marker gen RF sweep out out tO ORDER SEND BANK CHECK OR MONEY ORDER TO CANTON MODEL PRODUCTS PO BOX 6063 CANTON OHIO 44706 OR CALL 216 4541539 FOR IMMEDIATE COD SHIPMENT 06017 Ft Meyers FL 33908 PhoneRC Aerobatics/Van Putteattendance despitethe high quality ofthe contest 813 936-2397and outstanding traditional Saturday night International Crystal Manufacturing Co 20Continued page 41supper serve Well year 43 Pattern N Lee Oklahoma City OK 7310212 Sport Scale contestants delighted share boiled shrimp steamed crab supper Crescent City Radio Control Club members secret out other crashed airplanes cant repaired just well dont some give try certainly beats starting scratch way Ive often remarked annual New Orleans contest best kept secrets South because ofoccasional spirse PC Boards John R Lange 1700 N 37th Ave Stone Park IL 60165Ron Van Putie Ill Sleepy Oaks Rd Fr Walton Beach FL 32548 RC Giant Scale/Beckman Continued page 43 conversation Dave Scully Aero Compo sites 411 Townsend Place Dayton OH 45431 mentioned quarter-scale kit Hal Krierversion Great Lakes Special kit almost unknown dont really push said would send some information busy before got Ive busy havent done anything until now meantime saw Dave Toledo chance see plane fuselage comes kit fiberglass fuselage/foam wing kit too common Giant Scale fuselage has stringer detail molded cap strips wing foam before covering wind up realistic looking construction model designed prop drive setup originally has since changed Quadra significant improvement performance Daves picture-taking technique worth comment dont know other way vuure going get kind siew Giant Scale aircraft inside house Continued page 114 February 1982111 John Lange poseswith models frontot car isequipped listen current RC frequencies through car radio professional microwave technician John has made use RC frequency monitoring gear work well
Edition: Model Aviation - 1982/02
Page Numbers: 36, 37, 38, 39, 110, 111
IIeceiViq CoqVerters NC Frequeqcies youve done some electronics work can find way around schematic heres building pro ject useful device converter allows listen RC fre quency portable radio club should have U John R Lange WOULD YOU LIKE able monitor RC frequency before fly chase down interference check giltches Would like sure some elses transmit ter impound area car hasnt left get glitched would like sure interference got am ham radio operator fly RC 6 meters 53 MHz wanted check band before flying since 6 meters can fested ignition engine noise amateur FM repeaters other things devel oped -this receiving converter circuits ARRL Radio Amateurs VHF Manual Anyone has built Heathkit Ace kit ought able build Most parts can easily obtained local Radio AC Frequency Monitor can easily mounted under car dash Just swap plugs switch between RC frequencies broadcast stations 4 METER AND 6 METER RC FREQUENCY CONVERTER IN 5 I/4x3Mx2 I/8 ALUMINUM BOX WITH UNDER DASH MOUNTING BRACKETS RADIO eOe eWe eOe ANTENNA 0 4 meter shown 6 meter has no 72-75 switch 2 0 eOe INPUT scale inches OL........1 3 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER PARTS LAYOUT IN 5 1/4 x 3x2 I/B ALUMINUM BOX BUDD CU 210GB CU-3006A RADIO SHACK 270-238 LMB 780 ALECTRO H4T741l/2x5/8cutout shield socket coil leads away chassis go gates drains leads closest chassis go terminal strip ground lugs bypass capacitors Cb Shack store receiving crystals can mallordered JAN Crystals International Crystals Addresses appear end article receiving converter can built either two ways version small mini box mounted under dash car uses cars whip antenna power fuse block Its connected car AM radio radio tuner selects chan nel want listen puts out car speaker listen radio simply turn off converter second version portable con tains its own pocket-size AM receiver 1 C U Cq o 10 0 0 U 0 0 S2 omitted 6 meter Cape inside nverters crystal iscover area rO between gate ground lug oNEINcNSCALE second version has seven-position rotary switch connected seven crystals can tune seven RC frequencies 4-me ter RC band way tune TV set first converter 6 meters hooked up car radio has two-FET-transistor cascode RF amplifier stage FET transistor mixer 52 MHz crystal-controlled FET transistor oscillator use 2-ft coaxial extension lead Moto rola male plugs connect car radio cord Part No 12-1314 Radio Shack listen RC frequencies unplug car antenna lead back antenna jack J3 plug front input Ji turn 36 Model Aviation eR @eQe e ee0 ONeBrW7208 680 01087216 760 0408 7224 840 ______Or-SO 7240 VoSO 7232 920 OFF727500-08 7296 1560 shielduse bottom hole 191of ground lugInsulat cbDL33Output RFC Cb4 RFC LI stand end wisleeveshield use sleevin 4-40 check clearanceY2 antennato fuse center pin tobngsleeving1-I25to shield use bottom hole gnd lugi-I45v 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER INTERNAL SHIELDS round off use 5052-H 32 sheet aluminum corners 0 0 o make bends vise dashed lines holes 3/32 diameter 10 A-I converter tune car radio tween 1100 1500 AM dial gives 531 MHz 1100 535 1500 pre-set two radio push-buttons correct spot two RC frequencies use just hit buttonjust like dialing AM station converter setup 4-me ter band 72 76 MHz works same way 4-meter converter can pick up sev en RC frequencies two receiving crystals Since first six frequencies tween 72080 72960 MHz less MHz apart 714 MHz crystal con verter local oscillator will aliow tune ali between 540 1600 radio diaL seventh frequency 75640 picked up switching 74640 crystal appears 1000 dial enough range either side bands receive adjacent interference sources get new frequencies hope tune weli portable converter has small under$10 Radio Shack AM pocket portable radio catalog number 12-171 12-172 tuned 1000 dial seven re ceiving crystals converter 1 MHz low corresponding RC frequency mounted poles rotary switch nine-volt battery series two AA pencells gives 12 volts needed convert er radio course has its own battery might consider building circuit aluminum box chassis case small car radio whip antenna instead pocket portable radio would allow power whole works 12-volt Gel Cell Ni-Cad pack also eliminates AM broadcasts pocket portable radio alignment G C6 I5ch pf__ --12v PORTABLERFC v--Gb OUTPUT FOR POCKET RECEIVER FUSE HOLDER MOUNTING DETAIL 25A fuse to~yJ424 scaleinchesIlockwt~T7i&I 0I23 Um~hiU LFLJ4-40x3/4 BOTTOM VIEW OF TRANSISTORS SG D DQ SQgroundD casecase round 2N5485 2N5486 ECG -312 Ddrain Ssource 2N4416 Ggate will occasionally pick up stations close 1000 dial Construction under-dash version converter built 51h x 3 x 2-1/8 alum inum mini-box portable version built cuVcEae 3ground lead short use 10 x 6 x 2 aluminum chassis bottom cover Physical parts placement fol lows schematic drawing inputs left outputs right oscillator section lower middle Sockets used transistors eliminate heat damage 4 METER AND 6 METER RECEIVNG CONVERTER FOR RC FREQUENCIES cascadeR F amplifiermixer RFC shield Cb IL3L4D QI SC6 70 CR1 _Cb. I8Cb 4 12v 1 r crystal controlled 33k local oscillator ll r~rmL1I output car O5mtradio SIA12 ant nna 121 Sib 25a CR3 i141145v 1 switch rotaryL switch tears 2 cryiols February 1982 37 About Author John R Lange has flying models since 1950s mostiy Free Flight Gas Old-Timer RC Assist Sailpianes systems engi neer microwave communications has worked TV tuner IF design John decided build RC frequency converters described after Dayton SAM Championships John tells us occasionally files seven-mile-square field converters handy see activity around since field large also help him work checking leakage communi cations equipment 70 MHz range would ordinarily have detec ted spectrum analyzer Presently member SOAR Lisle Aero RC Club John brings impressive technical skill bear RC interference problem BANDPASS CURVES 72MHz7 73MHz 535MHz 76 C4I2OpfC4l8Opf52 crystal osc freq shows curve PEAK TO PEAK RF DEMODULATOR TEST PROBE converter c output chassis ground 3 subminiature other coax oscilloscope mount 5 lug terminal strip soldering shortened transistor leads trimming about 3/16 fit socket better less likely jarred out Since transistors have different lead connections carefully ori ent leads after checking bottom views Plug transistors after wiring soldering finished make sure power plug aluminum shielding shown drawings isolates input output RF amplifier coils oscillator compart ment Its cut Reynolds sheet aluminum obtained hardware store installed after nearly other parts mounted Drill A-in holes shielding power injection output oscillator power output leads mixer Use sleeving shrink tubing long component leads Two reverse-connected 1N914 diodes wired across input terminals protec tion against excessive input signals No printed circuit boards necessary Editor PC boards available ad dress listed end article Wiring point-to-point between sockets minia ture terminal strips mounted 2-56 screws nuts lock washers bought several 5-lug miniature terminal strips trimmed off excess tugs sidecutters Component lead lengths should kept minimum especially 001 mf 470 pf 05 mf bypass capacitors C6 gate lead Q2 should short direct possible mixer output converter portable unit coupled ferrite rod tenna portable AM radio wrapping eight turns around antenna Shield interconnecting lead brald use short piece 2-conductor shielded wire connection helps minimize interfer ence AM broadcast stations near dial setting radio iron core tuned coils wound A-in diameter forms Miller 45004 forms will work other possibles A-in VHF coil forms James Mullen Cambridge Thermionic Cambion Coils old tube-type TV 45 MHz IF stage could stripped re wound coils RF chokes wound enamel- nylon-coated solid copper magnet wire can wind nice tight coils holding form both hands wire spool between knees Scrape sulation off tin wire ends before fastening RF choke 1-watt resistor File 1/16-in notch opposite edges 1-watt resistor help keep wire un raveling Coil start finish turns solder ed rings used Miller forms held down 1/8-in strips black plastic electrical tape wrapped around form lead Paint coils RF chokes GC Products Polystyrene Q Dope after wind ing Dont use model cement unless polystyrene-type Testors tube cement plastic models works fine 4-meter converter coil L5 its output link L6 used switched crystal frequencies found some weak transistors crystals wouldnt oscillate between highest crystal frequency 74640 MHz lower six frequencies between 7 1080 7 1960 MHz switched-in 22 pf capacitor low fre quencies corrected problem also opened switched between gate Q4 crystals rotary switch crystals connected common ground lug under mounting post nut switch common rotary switch contact tied directly gate Q4 Place switch close Q4 possible minimize stray capacity inductance speci fied second gang can used switch 22 pf capacitor align converter first get Q4 os cillate Turn radio connected J2 38 Model Aviation PARTS LIST 4-Meter 72 76 MI-lzJ6-Meter 53 535 MHz Li 21/2 turns No 28 wire over grounded endLi 3 turns No 28 wire over grounded end of L2 2 9 turns No 28 -in formL2 11 turns No 28 /4-in form L3 6 turns No 28L3 10 turns No 28 L4 512 turns No 28L4 9 turns No 28 L5 6 turns No 24L5 6 turns No 24 L6 1 turn No 24 over bypassed end L5L6 1 turn No 24 over bypassed end L5 L7 needed 8 turns No 24 wound over windings portable radios ferrite antenna RFC 25 turns No 28RFC 30 turns No 30 Cb 470 pf disk ceramic 25V moreCb 001 mf disk ceramic 25V C15pfC1l5pf C2lOpfC2lOpf C3 10 pfC3 10 pf C4 120 pfC4 330 pf C5 10 pfC5 20 pf C6 220 pf 47 pf car radioC6 330 pf 47 pf car radio Parts common both units Qi Q2 Q3 Q4 VHF UHF amplifier FET transistor Motorola 2N5485 2N5486 2N4416 Sylvania ECG-3 12 GE FET-3 CR1 CR2 1N914 silicon diodes CR3 20-volt 1-watt zener diode Y1 Y2 Series Resonance Fifth Overtone frequency crystal HC18/U holder see Frequency Crystal Selection Chart Fl 25-amp fuse clip holder Ji J2 J3 Receptacle Motorola-type broadcast antenna plug Radio Shack 274-712 H Smith 1207 J4 Four contact TRW cinch plug angle brackets P304-AB Cable socket TRW cinch S-304CCT Si Double pole double throw subminiature toggle switch S2 Double pole double throw subminiature toggle switch 2-section 2-pole 11-posItIon nonshorting ceramic rotary switch Centralab type 2513 Newark 22F416 Set seven positions Transistor sockets Radio Shack 276-548 Calectro-Cinch F2-984 5-lug miniature terminal strips Voitrex LTS-505C Newark 23N3990 Calectro F3-216 /4-in dia VHF iron core tuned coil forms Similar Miller 45004 20A000-4 Bell dustries Miller Div 19070 Reycs Ave Box 5285 Compton CA 90224 Milien 69048 69058 Millen Components 42A Pleasant St Stoneham MA 02180 Color-coded labels rotary swith positions Heathkit 390-919 Notes Chokes wound over 470K 1-watt Alien Bradley TRW Ohmite carbon composition resistor resistors /4-watt 10% coils RFC chokes wound solid enamel- soidereze-coated magnet wire Belden 8054 No 28 8055 No 30 8052 No 24 Fuse holder can optional builder 82-ohm 1W resistor reduced 82-ohm /4W resistor no fuse Turn up volume listen closely rushing noise speaker Now turn converter noise should increase Ad just iron core L5 until does Check crystal oscillates switched can whipping up peak-topeak demodulator test probe shown drawing Connect DC oscilloscope digital voltmeter Touch output link L6 chassis ground should obtain 2 volt better adjust L5 highest read ing can get just before oscillator quits Usually about 08 10 volt no oscillation obtained reduce coupling L6 L5 spreading open L6 sliding below bypassed end L5 still dont get oscillation remove iron core L5 slowly slide brass 10-3 2 8-32 screw end coil oscil lation occurs means L5 too large spread windings apart take off turn check iron core again Connect short whip antenna piece wire about foot long converter input Ji Turn RC transmitter leave antenna collapsed Turn AM radio converter tone buzz transmitter Back transmitter away retune radio loudest buzz Now move FREQUENCY CRYSTAL SELECTION CHART Portable Radio Unit RCV Crystal FrequencyFrequency 72080 MHz71080 MHz 72160 MHz71160 MHz 72240 MHz71240 MHz 72320 MHz71320MHz 72400MHz71400MHz 72960 MHz71960 MHz 75640 MHz74640 MHz 53100MHz 53200MHz 53300 MHz 53400 MHz CO53500 MHz transmitter farther away until buzz weak Adjust iron cores L2 L3 L4 loudest buzz L2 will tune broadly L3 L4 sharply Make sure both 72 MHz 75 MHz transmitter can heard sharper output indication can obtained using oscilloscope de modulator test probe connect probe output 12 drain Q3 may get better indication scope tem porarily removing L7 putting 150-ohm resistor its place 52100 MHz 52200 MHz 52300 MHz 52400 MHz 52500 MHz Tunable Car Radio Unit V Crystal AM Dial Frequency Reading 71400 MHz 680 KHz 760 KHz 840 KHz 920 KHz 1000KHz 1560 KHz 74640 MHz 1000 KHz 52000 MHz 1100 KHz 1200 KHz 1300 KHz 1400 KHz 1500 KHz AM Dial Reading 1000 KHz 1000 KHz 1000 KHz really want perfectionist can use sweep alignment setup shown VHF TV sweep marker signal generator will pick up 6-meter converter low end TV Channel 2 the 4-me ter converter high end Channel 4 low end Channel 5 Tune L2 maxi mize mid-part curve L3 L4 maximize curve amplitude po sition curves always tilted since no mixer peaking coil design Continued page 110 February 1982 39 Finished 6-meter 4-meter converters described text plugging car radio antenna converter connecting radio can tune listen RC frequencies two smaller units connection yourcar radio big unit middle contains small transistor radio set crystals forthe RC frequencies stand-alone operation Frequency Switching big unit contains small radio receiverright set receiving crystals attached rotary switch left Smaller converter 6-meter ham band needs internal shield Parts arrangement relatively simple PC boards available Insides 4-meter converter shows aluminum shielding around RF sections Two crystals allow tune across 72-75 MHz Text describes wind RF chokes will need wire connected test probe also described precise tuning LEADER IN SMALL AIRFOIL TECHNOLOGY MASTER AIRSCREW MBSW6 b3ISVV4MASTER IMPROVED THROUGH FOUR YEARS OF PRODUCTION THE G/F SERIES IS UNEQUALED FOR PERFORMANCE & DURABILITY AVAILABLE WORLDWIDE THROUGH 131 DISTRIBUTORS WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 lASTER AIIISCiIIW PRESENTS BALSA STRIPPER 495 AT YOUR DEALER PRECISION STRIP WOOD TO INS FROM BALSA SHEET ALSO FOR DRAFTING AND PHOTO MATS USES TYPE II BLADE SUPER TOOL T PRICE WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 CANTON MODEL PRODUCTS Presents Dip Stick FAST QUICK / EASY TO FINISH D540 55 SPAN 560 SQ IN WING LOADING 165-20 OZ 29-45 ENGINE 43 LENGTH 3 OR 4 CHANNEL PRICE 4995 ADD 4 SHIPPING CHARGE DS 60 641/2 SPAN 672 SQ IN WING LOADING 20-22 OZ 46-60 ENGINE 48 LENGTH 3 OR 4 CHANNEL PRICE 5995 EXTREMELYADD 6 SHIPPING RUGGED TRAINER CHARGE WITH SYMMETRICAL AIRFOIL FOR AEROBATIC FLYING HIGHLY PRE-FABRICATED KIT INCLUDES PRE-SHEETED BALSA FOAM WINGS PRE-BUILT JIG ASSEMBLED WOOD FUSELAGE PRE-SHAPE BALSA TAIL ASSEMBLY PRE-FORMED LANDING GEAR TAIL WHEEL AND AILERON WIRES INSTRUCTION SHEET WITH FULLY ILLUSTRATED ASSEMBLY DRAWINGS tow P ceo Cannot 0 SCOUR Doale s Black Widow/Baker Continued page 30 slowly fixed fuel pick-ups will starve engine slow roll Black Widow dream touch-andgoes Use wide pattern set up long final approach lowest throttle does want lose altitude final approach model assumes rather flat attitude can held right down ground Application full throttle results immediate return air Frequency Scanner/Lange Continued page 39 wish use RC transmitter check accuracy signal generator coupling L6 L5 tuning [5 should checked peak curve amplitude con sistent good oscillator starting have made some sensitivity tests several converters signal generator calibrated output could usually detect 01 RG58/u RG59AJ large wheels landings grass field have no-bounce greasers Singleengine performance excellent allows plenty time set up normal landing approach ailerons sufficient handle singleengine situations rudders very effec tive want use Despite its size small engines P-6 handles like trainer docile has no hidden faults waiting bite goes point Best does great deal realism microvolt signals three microvolt sig nals boomed through loud clear Consid ering RC receivers rated two three microvolts sensitivity thats quite ac ceptable best results obtained using a3- 5-ft extended whip antenna 4 6 meters usually can hear RC fliers transmitter two four miles field over flat terrain car engine turned off Sources Crystals JAN Crystals 2400 Crystal Dr PO Box I12v conte-jr scope vert hor ground generator scope converter aluminum copper sheet bench 110 Model Aviation BANDPASS ALIGNMENT WITH SWEEP GENERATOR AND SCOPE 00 VHF sweep marker gen RF sweep out out tO ORDER SEND BANK CHECK OR MONEY ORDER TO CANTON MODEL PRODUCTS PO BOX 6063 CANTON OHIO 44706 OR CALL 216 4541539 FOR IMMEDIATE COD SHIPMENT 06017 Ft Meyers FL 33908 PhoneRC Aerobatics/Van Putteattendance despitethe high quality ofthe contest 813 936-2397and outstanding traditional Saturday night International Crystal Manufacturing Co 20Continued page 41supper serve Well year 43 Pattern N Lee Oklahoma City OK 7310212 Sport Scale contestants delighted share boiled shrimp steamed crab supper Crescent City Radio Control Club members secret out other crashed airplanes cant repaired just well dont some give try certainly beats starting scratch way Ive often remarked annual New Orleans contest best kept secrets South because ofoccasional spirse PC Boards John R Lange 1700 N 37th Ave Stone Park IL 60165Ron Van Putie Ill Sleepy Oaks Rd Fr Walton Beach FL 32548 RC Giant Scale/Beckman Continued page 43 conversation Dave Scully Aero Compo sites 411 Townsend Place Dayton OH 45431 mentioned quarter-scale kit Hal Krierversion Great Lakes Special kit almost unknown dont really push said would send some information busy before got Ive busy havent done anything until now meantime saw Dave Toledo chance see plane fuselage comes kit fiberglass fuselage/foam wing kit too common Giant Scale fuselage has stringer detail molded cap strips wing foam before covering wind up realistic looking construction model designed prop drive setup originally has since changed Quadra significant improvement performance Daves picture-taking technique worth comment dont know other way vuure going get kind siew Giant Scale aircraft inside house Continued page 114 February 1982111 John Lange poseswith models frontot car isequipped listen current RC frequencies through car radio professional microwave technician John has made use RC frequency monitoring gear work well
Edition: Model Aviation - 1982/02
Page Numbers: 36, 37, 38, 39, 110, 111
IIeceiViq CoqVerters NC Frequeqcies youve done some electronics work can find way around schematic heres building pro ject useful device converter allows listen RC fre quency portable radio club should have U John R Lange WOULD YOU LIKE able monitor RC frequency before fly chase down interference check giltches Would like sure some elses transmit ter impound area car hasnt left get glitched would like sure interference got am ham radio operator fly RC 6 meters 53 MHz wanted check band before flying since 6 meters can fested ignition engine noise amateur FM repeaters other things devel oped -this receiving converter circuits ARRL Radio Amateurs VHF Manual Anyone has built Heathkit Ace kit ought able build Most parts can easily obtained local Radio AC Frequency Monitor can easily mounted under car dash Just swap plugs switch between RC frequencies broadcast stations 4 METER AND 6 METER RC FREQUENCY CONVERTER IN 5 I/4x3Mx2 I/8 ALUMINUM BOX WITH UNDER DASH MOUNTING BRACKETS RADIO eOe eWe eOe ANTENNA 0 4 meter shown 6 meter has no 72-75 switch 2 0 eOe INPUT scale inches OL........1 3 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER PARTS LAYOUT IN 5 1/4 x 3x2 I/B ALUMINUM BOX BUDD CU 210GB CU-3006A RADIO SHACK 270-238 LMB 780 ALECTRO H4T741l/2x5/8cutout shield socket coil leads away chassis go gates drains leads closest chassis go terminal strip ground lugs bypass capacitors Cb Shack store receiving crystals can mallordered JAN Crystals International Crystals Addresses appear end article receiving converter can built either two ways version small mini box mounted under dash car uses cars whip antenna power fuse block Its connected car AM radio radio tuner selects chan nel want listen puts out car speaker listen radio simply turn off converter second version portable con tains its own pocket-size AM receiver 1 C U Cq o 10 0 0 U 0 0 S2 omitted 6 meter Cape inside nverters crystal iscover area rO between gate ground lug oNEINcNSCALE second version has seven-position rotary switch connected seven crystals can tune seven RC frequencies 4-me ter RC band way tune TV set first converter 6 meters hooked up car radio has two-FET-transistor cascode RF amplifier stage FET transistor mixer 52 MHz crystal-controlled FET transistor oscillator use 2-ft coaxial extension lead Moto rola male plugs connect car radio cord Part No 12-1314 Radio Shack listen RC frequencies unplug car antenna lead back antenna jack J3 plug front input Ji turn 36 Model Aviation eR @eQe e ee0 ONeBrW7208 680 01087216 760 0408 7224 840 ______Or-SO 7240 VoSO 7232 920 OFF727500-08 7296 1560 shielduse bottom hole 191of ground lugInsulat cbDL33Output RFC Cb4 RFC LI stand end wisleeveshield use sleevin 4-40 check clearanceY2 antennato fuse center pin tobngsleeving1-I25to shield use bottom hole gnd lugi-I45v 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER INTERNAL SHIELDS round off use 5052-H 32 sheet aluminum corners 0 0 o make bends vise dashed lines holes 3/32 diameter 10 A-I converter tune car radio tween 1100 1500 AM dial gives 531 MHz 1100 535 1500 pre-set two radio push-buttons correct spot two RC frequencies use just hit buttonjust like dialing AM station converter setup 4-me ter band 72 76 MHz works same way 4-meter converter can pick up sev en RC frequencies two receiving crystals Since first six frequencies tween 72080 72960 MHz less MHz apart 714 MHz crystal con verter local oscillator will aliow tune ali between 540 1600 radio diaL seventh frequency 75640 picked up switching 74640 crystal appears 1000 dial enough range either side bands receive adjacent interference sources get new frequencies hope tune weli portable converter has small under$10 Radio Shack AM pocket portable radio catalog number 12-171 12-172 tuned 1000 dial seven re ceiving crystals converter 1 MHz low corresponding RC frequency mounted poles rotary switch nine-volt battery series two AA pencells gives 12 volts needed convert er radio course has its own battery might consider building circuit aluminum box chassis case small car radio whip antenna instead pocket portable radio would allow power whole works 12-volt Gel Cell Ni-Cad pack also eliminates AM broadcasts pocket portable radio alignment G C6 I5ch pf__ --12v PORTABLERFC v--Gb OUTPUT FOR POCKET RECEIVER FUSE HOLDER MOUNTING DETAIL 25A fuse to~yJ424 scaleinchesIlockwt~T7i&I 0I23 Um~hiU LFLJ4-40x3/4 BOTTOM VIEW OF TRANSISTORS SG D DQ SQgroundD casecase round 2N5485 2N5486 ECG -312 Ddrain Ssource 2N4416 Ggate will occasionally pick up stations close 1000 dial Construction under-dash version converter built 51h x 3 x 2-1/8 alum inum mini-box portable version built cuVcEae 3ground lead short use 10 x 6 x 2 aluminum chassis bottom cover Physical parts placement fol lows schematic drawing inputs left outputs right oscillator section lower middle Sockets used transistors eliminate heat damage 4 METER AND 6 METER RECEIVNG CONVERTER FOR RC FREQUENCIES cascadeR F amplifiermixer RFC shield Cb IL3L4D QI SC6 70 CR1 _Cb. I8Cb 4 12v 1 r crystal controlled 33k local oscillator ll r~rmL1I output car O5mtradio SIA12 ant nna 121 Sib 25a CR3 i141145v 1 switch rotaryL switch tears 2 cryiols February 1982 37 About Author John R Lange has flying models since 1950s mostiy Free Flight Gas Old-Timer RC Assist Sailpianes systems engi neer microwave communications has worked TV tuner IF design John decided build RC frequency converters described after Dayton SAM Championships John tells us occasionally files seven-mile-square field converters handy see activity around since field large also help him work checking leakage communi cations equipment 70 MHz range would ordinarily have detec ted spectrum analyzer Presently member SOAR Lisle Aero RC Club John brings impressive technical skill bear RC interference problem BANDPASS CURVES 72MHz7 73MHz 535MHz 76 C4I2OpfC4l8Opf52 crystal osc freq shows curve PEAK TO PEAK RF DEMODULATOR TEST PROBE converter c output chassis ground 3 subminiature other coax oscilloscope mount 5 lug terminal strip soldering shortened transistor leads trimming about 3/16 fit socket better less likely jarred out Since transistors have different lead connections carefully ori ent leads after checking bottom views Plug transistors after wiring soldering finished make sure power plug aluminum shielding shown drawings isolates input output RF amplifier coils oscillator compart ment Its cut Reynolds sheet aluminum obtained hardware store installed after nearly other parts mounted Drill A-in holes shielding power injection output oscillator power output leads mixer Use sleeving shrink tubing long component leads Two reverse-connected 1N914 diodes wired across input terminals protec tion against excessive input signals No printed circuit boards necessary Editor PC boards available ad dress listed end article Wiring point-to-point between sockets minia ture terminal strips mounted 2-56 screws nuts lock washers bought several 5-lug miniature terminal strips trimmed off excess tugs sidecutters Component lead lengths should kept minimum especially 001 mf 470 pf 05 mf bypass capacitors C6 gate lead Q2 should short direct possible mixer output converter portable unit coupled ferrite rod tenna portable AM radio wrapping eight turns around antenna Shield interconnecting lead brald use short piece 2-conductor shielded wire connection helps minimize interfer ence AM broadcast stations near dial setting radio iron core tuned coils wound A-in diameter forms Miller 45004 forms will work other possibles A-in VHF coil forms James Mullen Cambridge Thermionic Cambion Coils old tube-type TV 45 MHz IF stage could stripped re wound coils RF chokes wound enamel- nylon-coated solid copper magnet wire can wind nice tight coils holding form both hands wire spool between knees Scrape sulation off tin wire ends before fastening RF choke 1-watt resistor File 1/16-in notch opposite edges 1-watt resistor help keep wire un raveling Coil start finish turns solder ed rings used Miller forms held down 1/8-in strips black plastic electrical tape wrapped around form lead Paint coils RF chokes GC Products Polystyrene Q Dope after wind ing Dont use model cement unless polystyrene-type Testors tube cement plastic models works fine 4-meter converter coil L5 its output link L6 used switched crystal frequencies found some weak transistors crystals wouldnt oscillate between highest crystal frequency 74640 MHz lower six frequencies between 7 1080 7 1960 MHz switched-in 22 pf capacitor low fre quencies corrected problem also opened switched between gate Q4 crystals rotary switch crystals connected common ground lug under mounting post nut switch common rotary switch contact tied directly gate Q4 Place switch close Q4 possible minimize stray capacity inductance speci fied second gang can used switch 22 pf capacitor align converter first get Q4 os cillate Turn radio connected J2 38 Model Aviation PARTS LIST 4-Meter 72 76 MI-lzJ6-Meter 53 535 MHz Li 21/2 turns No 28 wire over grounded endLi 3 turns No 28 wire over grounded end of L2 2 9 turns No 28 -in formL2 11 turns No 28 /4-in form L3 6 turns No 28L3 10 turns No 28 L4 512 turns No 28L4 9 turns No 28 L5 6 turns No 24L5 6 turns No 24 L6 1 turn No 24 over bypassed end L5L6 1 turn No 24 over bypassed end L5 L7 needed 8 turns No 24 wound over windings portable radios ferrite antenna RFC 25 turns No 28RFC 30 turns No 30 Cb 470 pf disk ceramic 25V moreCb 001 mf disk ceramic 25V C15pfC1l5pf C2lOpfC2lOpf C3 10 pfC3 10 pf C4 120 pfC4 330 pf C5 10 pfC5 20 pf C6 220 pf 47 pf car radioC6 330 pf 47 pf car radio Parts common both units Qi Q2 Q3 Q4 VHF UHF amplifier FET transistor Motorola 2N5485 2N5486 2N4416 Sylvania ECG-3 12 GE FET-3 CR1 CR2 1N914 silicon diodes CR3 20-volt 1-watt zener diode Y1 Y2 Series Resonance Fifth Overtone frequency crystal HC18/U holder see Frequency Crystal Selection Chart Fl 25-amp fuse clip holder Ji J2 J3 Receptacle Motorola-type broadcast antenna plug Radio Shack 274-712 H Smith 1207 J4 Four contact TRW cinch plug angle brackets P304-AB Cable socket TRW cinch S-304CCT Si Double pole double throw subminiature toggle switch S2 Double pole double throw subminiature toggle switch 2-section 2-pole 11-posItIon nonshorting ceramic rotary switch Centralab type 2513 Newark 22F416 Set seven positions Transistor sockets Radio Shack 276-548 Calectro-Cinch F2-984 5-lug miniature terminal strips Voitrex LTS-505C Newark 23N3990 Calectro F3-216 /4-in dia VHF iron core tuned coil forms Similar Miller 45004 20A000-4 Bell dustries Miller Div 19070 Reycs Ave Box 5285 Compton CA 90224 Milien 69048 69058 Millen Components 42A Pleasant St Stoneham MA 02180 Color-coded labels rotary swith positions Heathkit 390-919 Notes Chokes wound over 470K 1-watt Alien Bradley TRW Ohmite carbon composition resistor resistors /4-watt 10% coils RFC chokes wound solid enamel- soidereze-coated magnet wire Belden 8054 No 28 8055 No 30 8052 No 24 Fuse holder can optional builder 82-ohm 1W resistor reduced 82-ohm /4W resistor no fuse Turn up volume listen closely rushing noise speaker Now turn converter noise should increase Ad just iron core L5 until does Check crystal oscillates switched can whipping up peak-topeak demodulator test probe shown drawing Connect DC oscilloscope digital voltmeter Touch output link L6 chassis ground should obtain 2 volt better adjust L5 highest read ing can get just before oscillator quits Usually about 08 10 volt no oscillation obtained reduce coupling L6 L5 spreading open L6 sliding below bypassed end L5 still dont get oscillation remove iron core L5 slowly slide brass 10-3 2 8-32 screw end coil oscil lation occurs means L5 too large spread windings apart take off turn check iron core again Connect short whip antenna piece wire about foot long converter input Ji Turn RC transmitter leave antenna collapsed Turn AM radio converter tone buzz transmitter Back transmitter away retune radio loudest buzz Now move FREQUENCY CRYSTAL SELECTION CHART Portable Radio Unit RCV Crystal FrequencyFrequency 72080 MHz71080 MHz 72160 MHz71160 MHz 72240 MHz71240 MHz 72320 MHz71320MHz 72400MHz71400MHz 72960 MHz71960 MHz 75640 MHz74640 MHz 53100MHz 53200MHz 53300 MHz 53400 MHz CO53500 MHz transmitter farther away until buzz weak Adjust iron cores L2 L3 L4 loudest buzz L2 will tune broadly L3 L4 sharply Make sure both 72 MHz 75 MHz transmitter can heard sharper output indication can obtained using oscilloscope de modulator test probe connect probe output 12 drain Q3 may get better indication scope tem porarily removing L7 putting 150-ohm resistor its place 52100 MHz 52200 MHz 52300 MHz 52400 MHz 52500 MHz Tunable Car Radio Unit V Crystal AM Dial Frequency Reading 71400 MHz 680 KHz 760 KHz 840 KHz 920 KHz 1000KHz 1560 KHz 74640 MHz 1000 KHz 52000 MHz 1100 KHz 1200 KHz 1300 KHz 1400 KHz 1500 KHz AM Dial Reading 1000 KHz 1000 KHz 1000 KHz really want perfectionist can use sweep alignment setup shown VHF TV sweep marker signal generator will pick up 6-meter converter low end TV Channel 2 the 4-me ter converter high end Channel 4 low end Channel 5 Tune L2 maxi mize mid-part curve L3 L4 maximize curve amplitude po sition curves always tilted since no mixer peaking coil design Continued page 110 February 1982 39 Finished 6-meter 4-meter converters described text plugging car radio antenna converter connecting radio can tune listen RC frequencies two smaller units connection yourcar radio big unit middle contains small transistor radio set crystals forthe RC frequencies stand-alone operation Frequency Switching big unit contains small radio receiverright set receiving crystals attached rotary switch left Smaller converter 6-meter ham band needs internal shield Parts arrangement relatively simple PC boards available Insides 4-meter converter shows aluminum shielding around RF sections Two crystals allow tune across 72-75 MHz Text describes wind RF chokes will need wire connected test probe also described precise tuning LEADER IN SMALL AIRFOIL TECHNOLOGY MASTER AIRSCREW MBSW6 b3ISVV4MASTER IMPROVED THROUGH FOUR YEARS OF PRODUCTION THE G/F SERIES IS UNEQUALED FOR PERFORMANCE & DURABILITY AVAILABLE WORLDWIDE THROUGH 131 DISTRIBUTORS WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 lASTER AIIISCiIIW PRESENTS BALSA STRIPPER 495 AT YOUR DEALER PRECISION STRIP WOOD TO INS FROM BALSA SHEET ALSO FOR DRAFTING AND PHOTO MATS USES TYPE II BLADE SUPER TOOL T PRICE WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 CANTON MODEL PRODUCTS Presents Dip Stick FAST QUICK / EASY TO FINISH D540 55 SPAN 560 SQ IN WING LOADING 165-20 OZ 29-45 ENGINE 43 LENGTH 3 OR 4 CHANNEL PRICE 4995 ADD 4 SHIPPING CHARGE DS 60 641/2 SPAN 672 SQ IN WING LOADING 20-22 OZ 46-60 ENGINE 48 LENGTH 3 OR 4 CHANNEL PRICE 5995 EXTREMELYADD 6 SHIPPING RUGGED TRAINER CHARGE WITH SYMMETRICAL AIRFOIL FOR AEROBATIC FLYING HIGHLY PRE-FABRICATED KIT INCLUDES PRE-SHEETED BALSA FOAM WINGS PRE-BUILT JIG ASSEMBLED WOOD FUSELAGE PRE-SHAPE BALSA TAIL ASSEMBLY PRE-FORMED LANDING GEAR TAIL WHEEL AND AILERON WIRES INSTRUCTION SHEET WITH FULLY ILLUSTRATED ASSEMBLY DRAWINGS tow P ceo Cannot 0 SCOUR Doale s Black Widow/Baker Continued page 30 slowly fixed fuel pick-ups will starve engine slow roll Black Widow dream touch-andgoes Use wide pattern set up long final approach lowest throttle does want lose altitude final approach model assumes rather flat attitude can held right down ground Application full throttle results immediate return air Frequency Scanner/Lange Continued page 39 wish use RC transmitter check accuracy signal generator coupling L6 L5 tuning [5 should checked peak curve amplitude con sistent good oscillator starting have made some sensitivity tests several converters signal generator calibrated output could usually detect 01 RG58/u RG59AJ large wheels landings grass field have no-bounce greasers Singleengine performance excellent allows plenty time set up normal landing approach ailerons sufficient handle singleengine situations rudders very effec tive want use Despite its size small engines P-6 handles like trainer docile has no hidden faults waiting bite goes point Best does great deal realism microvolt signals three microvolt sig nals boomed through loud clear Consid ering RC receivers rated two three microvolts sensitivity thats quite ac ceptable best results obtained using a3- 5-ft extended whip antenna 4 6 meters usually can hear RC fliers transmitter two four miles field over flat terrain car engine turned off Sources Crystals JAN Crystals 2400 Crystal Dr PO Box I12v conte-jr scope vert hor ground generator scope converter aluminum copper sheet bench 110 Model Aviation BANDPASS ALIGNMENT WITH SWEEP GENERATOR AND SCOPE 00 VHF sweep marker gen RF sweep out out tO ORDER SEND BANK CHECK OR MONEY ORDER TO CANTON MODEL PRODUCTS PO BOX 6063 CANTON OHIO 44706 OR CALL 216 4541539 FOR IMMEDIATE COD SHIPMENT 06017 Ft Meyers FL 33908 PhoneRC Aerobatics/Van Putteattendance despitethe high quality ofthe contest 813 936-2397and outstanding traditional Saturday night International Crystal Manufacturing Co 20Continued page 41supper serve Well year 43 Pattern N Lee Oklahoma City OK 7310212 Sport Scale contestants delighted share boiled shrimp steamed crab supper Crescent City Radio Control Club members secret out other crashed airplanes cant repaired just well dont some give try certainly beats starting scratch way Ive often remarked annual New Orleans contest best kept secrets South because ofoccasional spirse PC Boards John R Lange 1700 N 37th Ave Stone Park IL 60165Ron Van Putie Ill Sleepy Oaks Rd Fr Walton Beach FL 32548 RC Giant Scale/Beckman Continued page 43 conversation Dave Scully Aero Compo sites 411 Townsend Place Dayton OH 45431 mentioned quarter-scale kit Hal Krierversion Great Lakes Special kit almost unknown dont really push said would send some information busy before got Ive busy havent done anything until now meantime saw Dave Toledo chance see plane fuselage comes kit fiberglass fuselage/foam wing kit too common Giant Scale fuselage has stringer detail molded cap strips wing foam before covering wind up realistic looking construction model designed prop drive setup originally has since changed Quadra significant improvement performance Daves picture-taking technique worth comment dont know other way vuure going get kind siew Giant Scale aircraft inside house Continued page 114 February 1982111 John Lange poseswith models frontot car isequipped listen current RC frequencies through car radio professional microwave technician John has made use RC frequency monitoring gear work well
Edition: Model Aviation - 1982/02
Page Numbers: 36, 37, 38, 39, 110, 111
IIeceiViq CoqVerters NC Frequeqcies youve done some electronics work can find way around schematic heres building pro ject useful device converter allows listen RC fre quency portable radio club should have U John R Lange WOULD YOU LIKE able monitor RC frequency before fly chase down interference check giltches Would like sure some elses transmit ter impound area car hasnt left get glitched would like sure interference got am ham radio operator fly RC 6 meters 53 MHz wanted check band before flying since 6 meters can fested ignition engine noise amateur FM repeaters other things devel oped -this receiving converter circuits ARRL Radio Amateurs VHF Manual Anyone has built Heathkit Ace kit ought able build Most parts can easily obtained local Radio AC Frequency Monitor can easily mounted under car dash Just swap plugs switch between RC frequencies broadcast stations 4 METER AND 6 METER RC FREQUENCY CONVERTER IN 5 I/4x3Mx2 I/8 ALUMINUM BOX WITH UNDER DASH MOUNTING BRACKETS RADIO eOe eWe eOe ANTENNA 0 4 meter shown 6 meter has no 72-75 switch 2 0 eOe INPUT scale inches OL........1 3 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER PARTS LAYOUT IN 5 1/4 x 3x2 I/B ALUMINUM BOX BUDD CU 210GB CU-3006A RADIO SHACK 270-238 LMB 780 ALECTRO H4T741l/2x5/8cutout shield socket coil leads away chassis go gates drains leads closest chassis go terminal strip ground lugs bypass capacitors Cb Shack store receiving crystals can mallordered JAN Crystals International Crystals Addresses appear end article receiving converter can built either two ways version small mini box mounted under dash car uses cars whip antenna power fuse block Its connected car AM radio radio tuner selects chan nel want listen puts out car speaker listen radio simply turn off converter second version portable con tains its own pocket-size AM receiver 1 C U Cq o 10 0 0 U 0 0 S2 omitted 6 meter Cape inside nverters crystal iscover area rO between gate ground lug oNEINcNSCALE second version has seven-position rotary switch connected seven crystals can tune seven RC frequencies 4-me ter RC band way tune TV set first converter 6 meters hooked up car radio has two-FET-transistor cascode RF amplifier stage FET transistor mixer 52 MHz crystal-controlled FET transistor oscillator use 2-ft coaxial extension lead Moto rola male plugs connect car radio cord Part No 12-1314 Radio Shack listen RC frequencies unplug car antenna lead back antenna jack J3 plug front input Ji turn 36 Model Aviation eR @eQe e ee0 ONeBrW7208 680 01087216 760 0408 7224 840 ______Or-SO 7240 VoSO 7232 920 OFF727500-08 7296 1560 shielduse bottom hole 191of ground lugInsulat cbDL33Output RFC Cb4 RFC LI stand end wisleeveshield use sleevin 4-40 check clearanceY2 antennato fuse center pin tobngsleeving1-I25to shield use bottom hole gnd lugi-I45v 4 METER AND 6 METER RC FREQUENCY RECEIVING CONVERTER INTERNAL SHIELDS round off use 5052-H 32 sheet aluminum corners 0 0 o make bends vise dashed lines holes 3/32 diameter 10 A-I converter tune car radio tween 1100 1500 AM dial gives 531 MHz 1100 535 1500 pre-set two radio push-buttons correct spot two RC frequencies use just hit buttonjust like dialing AM station converter setup 4-me ter band 72 76 MHz works same way 4-meter converter can pick up sev en RC frequencies two receiving crystals Since first six frequencies tween 72080 72960 MHz less MHz apart 714 MHz crystal con verter local oscillator will aliow tune ali between 540 1600 radio diaL seventh frequency 75640 picked up switching 74640 crystal appears 1000 dial enough range either side bands receive adjacent interference sources get new frequencies hope tune weli portable converter has small under$10 Radio Shack AM pocket portable radio catalog number 12-171 12-172 tuned 1000 dial seven re ceiving crystals converter 1 MHz low corresponding RC frequency mounted poles rotary switch nine-volt battery series two AA pencells gives 12 volts needed convert er radio course has its own battery might consider building circuit aluminum box chassis case small car radio whip antenna instead pocket portable radio would allow power whole works 12-volt Gel Cell Ni-Cad pack also eliminates AM broadcasts pocket portable radio alignment G C6 I5ch pf__ --12v PORTABLERFC v--Gb OUTPUT FOR POCKET RECEIVER FUSE HOLDER MOUNTING DETAIL 25A fuse to~yJ424 scaleinchesIlockwt~T7i&I 0I23 Um~hiU LFLJ4-40x3/4 BOTTOM VIEW OF TRANSISTORS SG D DQ SQgroundD casecase round 2N5485 2N5486 ECG -312 Ddrain Ssource 2N4416 Ggate will occasionally pick up stations close 1000 dial Construction under-dash version converter built 51h x 3 x 2-1/8 alum inum mini-box portable version built cuVcEae 3ground lead short use 10 x 6 x 2 aluminum chassis bottom cover Physical parts placement fol lows schematic drawing inputs left outputs right oscillator section lower middle Sockets used transistors eliminate heat damage 4 METER AND 6 METER RECEIVNG CONVERTER FOR RC FREQUENCIES cascadeR F amplifiermixer RFC shield Cb IL3L4D QI SC6 70 CR1 _Cb. I8Cb 4 12v 1 r crystal controlled 33k local oscillator ll r~rmL1I output car O5mtradio SIA12 ant nna 121 Sib 25a CR3 i141145v 1 switch rotaryL switch tears 2 cryiols February 1982 37 About Author John R Lange has flying models since 1950s mostiy Free Flight Gas Old-Timer RC Assist Sailpianes systems engi neer microwave communications has worked TV tuner IF design John decided build RC frequency converters described after Dayton SAM Championships John tells us occasionally files seven-mile-square field converters handy see activity around since field large also help him work checking leakage communi cations equipment 70 MHz range would ordinarily have detec ted spectrum analyzer Presently member SOAR Lisle Aero RC Club John brings impressive technical skill bear RC interference problem BANDPASS CURVES 72MHz7 73MHz 535MHz 76 C4I2OpfC4l8Opf52 crystal osc freq shows curve PEAK TO PEAK RF DEMODULATOR TEST PROBE converter c output chassis ground 3 subminiature other coax oscilloscope mount 5 lug terminal strip soldering shortened transistor leads trimming about 3/16 fit socket better less likely jarred out Since transistors have different lead connections carefully ori ent leads after checking bottom views Plug transistors after wiring soldering finished make sure power plug aluminum shielding shown drawings isolates input output RF amplifier coils oscillator compart ment Its cut Reynolds sheet aluminum obtained hardware store installed after nearly other parts mounted Drill A-in holes shielding power injection output oscillator power output leads mixer Use sleeving shrink tubing long component leads Two reverse-connected 1N914 diodes wired across input terminals protec tion against excessive input signals No printed circuit boards necessary Editor PC boards available ad dress listed end article Wiring point-to-point between sockets minia ture terminal strips mounted 2-56 screws nuts lock washers bought several 5-lug miniature terminal strips trimmed off excess tugs sidecutters Component lead lengths should kept minimum especially 001 mf 470 pf 05 mf bypass capacitors C6 gate lead Q2 should short direct possible mixer output converter portable unit coupled ferrite rod tenna portable AM radio wrapping eight turns around antenna Shield interconnecting lead brald use short piece 2-conductor shielded wire connection helps minimize interfer ence AM broadcast stations near dial setting radio iron core tuned coils wound A-in diameter forms Miller 45004 forms will work other possibles A-in VHF coil forms James Mullen Cambridge Thermionic Cambion Coils old tube-type TV 45 MHz IF stage could stripped re wound coils RF chokes wound enamel- nylon-coated solid copper magnet wire can wind nice tight coils holding form both hands wire spool between knees Scrape sulation off tin wire ends before fastening RF choke 1-watt resistor File 1/16-in notch opposite edges 1-watt resistor help keep wire un raveling Coil start finish turns solder ed rings used Miller forms held down 1/8-in strips black plastic electrical tape wrapped around form lead Paint coils RF chokes GC Products Polystyrene Q Dope after wind ing Dont use model cement unless polystyrene-type Testors tube cement plastic models works fine 4-meter converter coil L5 its output link L6 used switched crystal frequencies found some weak transistors crystals wouldnt oscillate between highest crystal frequency 74640 MHz lower six frequencies between 7 1080 7 1960 MHz switched-in 22 pf capacitor low fre quencies corrected problem also opened switched between gate Q4 crystals rotary switch crystals connected common ground lug under mounting post nut switch common rotary switch contact tied directly gate Q4 Place switch close Q4 possible minimize stray capacity inductance speci fied second gang can used switch 22 pf capacitor align converter first get Q4 os cillate Turn radio connected J2 38 Model Aviation PARTS LIST 4-Meter 72 76 MI-lzJ6-Meter 53 535 MHz Li 21/2 turns No 28 wire over grounded endLi 3 turns No 28 wire over grounded end of L2 2 9 turns No 28 -in formL2 11 turns No 28 /4-in form L3 6 turns No 28L3 10 turns No 28 L4 512 turns No 28L4 9 turns No 28 L5 6 turns No 24L5 6 turns No 24 L6 1 turn No 24 over bypassed end L5L6 1 turn No 24 over bypassed end L5 L7 needed 8 turns No 24 wound over windings portable radios ferrite antenna RFC 25 turns No 28RFC 30 turns No 30 Cb 470 pf disk ceramic 25V moreCb 001 mf disk ceramic 25V C15pfC1l5pf C2lOpfC2lOpf C3 10 pfC3 10 pf C4 120 pfC4 330 pf C5 10 pfC5 20 pf C6 220 pf 47 pf car radioC6 330 pf 47 pf car radio Parts common both units Qi Q2 Q3 Q4 VHF UHF amplifier FET transistor Motorola 2N5485 2N5486 2N4416 Sylvania ECG-3 12 GE FET-3 CR1 CR2 1N914 silicon diodes CR3 20-volt 1-watt zener diode Y1 Y2 Series Resonance Fifth Overtone frequency crystal HC18/U holder see Frequency Crystal Selection Chart Fl 25-amp fuse clip holder Ji J2 J3 Receptacle Motorola-type broadcast antenna plug Radio Shack 274-712 H Smith 1207 J4 Four contact TRW cinch plug angle brackets P304-AB Cable socket TRW cinch S-304CCT Si Double pole double throw subminiature toggle switch S2 Double pole double throw subminiature toggle switch 2-section 2-pole 11-posItIon nonshorting ceramic rotary switch Centralab type 2513 Newark 22F416 Set seven positions Transistor sockets Radio Shack 276-548 Calectro-Cinch F2-984 5-lug miniature terminal strips Voitrex LTS-505C Newark 23N3990 Calectro F3-216 /4-in dia VHF iron core tuned coil forms Similar Miller 45004 20A000-4 Bell dustries Miller Div 19070 Reycs Ave Box 5285 Compton CA 90224 Milien 69048 69058 Millen Components 42A Pleasant St Stoneham MA 02180 Color-coded labels rotary swith positions Heathkit 390-919 Notes Chokes wound over 470K 1-watt Alien Bradley TRW Ohmite carbon composition resistor resistors /4-watt 10% coils RFC chokes wound solid enamel- soidereze-coated magnet wire Belden 8054 No 28 8055 No 30 8052 No 24 Fuse holder can optional builder 82-ohm 1W resistor reduced 82-ohm /4W resistor no fuse Turn up volume listen closely rushing noise speaker Now turn converter noise should increase Ad just iron core L5 until does Check crystal oscillates switched can whipping up peak-topeak demodulator test probe shown drawing Connect DC oscilloscope digital voltmeter Touch output link L6 chassis ground should obtain 2 volt better adjust L5 highest read ing can get just before oscillator quits Usually about 08 10 volt no oscillation obtained reduce coupling L6 L5 spreading open L6 sliding below bypassed end L5 still dont get oscillation remove iron core L5 slowly slide brass 10-3 2 8-32 screw end coil oscil lation occurs means L5 too large spread windings apart take off turn check iron core again Connect short whip antenna piece wire about foot long converter input Ji Turn RC transmitter leave antenna collapsed Turn AM radio converter tone buzz transmitter Back transmitter away retune radio loudest buzz Now move FREQUENCY CRYSTAL SELECTION CHART Portable Radio Unit RCV Crystal FrequencyFrequency 72080 MHz71080 MHz 72160 MHz71160 MHz 72240 MHz71240 MHz 72320 MHz71320MHz 72400MHz71400MHz 72960 MHz71960 MHz 75640 MHz74640 MHz 53100MHz 53200MHz 53300 MHz 53400 MHz CO53500 MHz transmitter farther away until buzz weak Adjust iron cores L2 L3 L4 loudest buzz L2 will tune broadly L3 L4 sharply Make sure both 72 MHz 75 MHz transmitter can heard sharper output indication can obtained using oscilloscope de modulator test probe connect probe output 12 drain Q3 may get better indication scope tem porarily removing L7 putting 150-ohm resistor its place 52100 MHz 52200 MHz 52300 MHz 52400 MHz 52500 MHz Tunable Car Radio Unit V Crystal AM Dial Frequency Reading 71400 MHz 680 KHz 760 KHz 840 KHz 920 KHz 1000KHz 1560 KHz 74640 MHz 1000 KHz 52000 MHz 1100 KHz 1200 KHz 1300 KHz 1400 KHz 1500 KHz AM Dial Reading 1000 KHz 1000 KHz 1000 KHz really want perfectionist can use sweep alignment setup shown VHF TV sweep marker signal generator will pick up 6-meter converter low end TV Channel 2 the 4-me ter converter high end Channel 4 low end Channel 5 Tune L2 maxi mize mid-part curve L3 L4 maximize curve amplitude po sition curves always tilted since no mixer peaking coil design Continued page 110 February 1982 39 Finished 6-meter 4-meter converters described text plugging car radio antenna converter connecting radio can tune listen RC frequencies two smaller units connection yourcar radio big unit middle contains small transistor radio set crystals forthe RC frequencies stand-alone operation Frequency Switching big unit contains small radio receiverright set receiving crystals attached rotary switch left Smaller converter 6-meter ham band needs internal shield Parts arrangement relatively simple PC boards available Insides 4-meter converter shows aluminum shielding around RF sections Two crystals allow tune across 72-75 MHz Text describes wind RF chokes will need wire connected test probe also described precise tuning LEADER IN SMALL AIRFOIL TECHNOLOGY MASTER AIRSCREW MBSW6 b3ISVV4MASTER IMPROVED THROUGH FOUR YEARS OF PRODUCTION THE G/F SERIES IS UNEQUALED FOR PERFORMANCE & DURABILITY AVAILABLE WORLDWIDE THROUGH 131 DISTRIBUTORS WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 lASTER AIIISCiIIW PRESENTS BALSA STRIPPER 495 AT YOUR DEALER PRECISION STRIP WOOD TO INS FROM BALSA SHEET ALSO FOR DRAFTING AND PHOTO MATS USES TYPE II BLADE SUPER TOOL T PRICE WINDSOR PROPELLER CO PO BOX 112 WINDSOR CA 95492 CANTON MODEL PRODUCTS Presents Dip Stick FAST QUICK / EASY TO FINISH D540 55 SPAN 560 SQ IN WING LOADING 165-20 OZ 29-45 ENGINE 43 LENGTH 3 OR 4 CHANNEL PRICE 4995 ADD 4 SHIPPING CHARGE DS 60 641/2 SPAN 672 SQ IN WING LOADING 20-22 OZ 46-60 ENGINE 48 LENGTH 3 OR 4 CHANNEL PRICE 5995 EXTREMELYADD 6 SHIPPING RUGGED TRAINER CHARGE WITH SYMMETRICAL AIRFOIL FOR AEROBATIC FLYING HIGHLY PRE-FABRICATED KIT INCLUDES PRE-SHEETED BALSA FOAM WINGS PRE-BUILT JIG ASSEMBLED WOOD FUSELAGE PRE-SHAPE BALSA TAIL ASSEMBLY PRE-FORMED LANDING GEAR TAIL WHEEL AND AILERON WIRES INSTRUCTION SHEET WITH FULLY ILLUSTRATED ASSEMBLY DRAWINGS tow P ceo Cannot 0 SCOUR Doale s Black Widow/Baker Continued page 30 slowly fixed fuel pick-ups will starve engine slow roll Black Widow dream touch-andgoes Use wide pattern set up long final approach lowest throttle does want lose altitude final approach model assumes rather flat attitude can held right down ground Application full throttle results immediate return air Frequency Scanner/Lange Continued page 39 wish use RC transmitter check accuracy signal generator coupling L6 L5 tuning [5 should checked peak curve amplitude con sistent good oscillator starting have made some sensitivity tests several converters signal generator calibrated output could usually detect 01 RG58/u RG59AJ large wheels landings grass field have no-bounce greasers Singleengine performance excellent allows plenty time set up normal landing approach ailerons sufficient handle singleengine situations rudders very effec tive want use Despite its size small engines P-6 handles like trainer docile has no hidden faults waiting bite goes point Best does great deal realism microvolt signals three microvolt sig nals boomed through loud clear Consid ering RC receivers rated two three microvolts sensitivity thats quite ac ceptable best results obtained using a3- 5-ft extended whip antenna 4 6 meters usually can hear RC fliers transmitter two four miles field over flat terrain car engine turned off Sources Crystals JAN Crystals 2400 Crystal Dr PO Box I12v conte-jr scope vert hor ground generator scope converter aluminum copper sheet bench 110 Model Aviation BANDPASS ALIGNMENT WITH SWEEP GENERATOR AND SCOPE 00 VHF sweep marker gen RF sweep out out tO ORDER SEND BANK CHECK OR MONEY ORDER TO CANTON MODEL PRODUCTS PO BOX 6063 CANTON OHIO 44706 OR CALL 216 4541539 FOR IMMEDIATE COD SHIPMENT 06017 Ft Meyers FL 33908 PhoneRC Aerobatics/Van Putteattendance despitethe high quality ofthe contest 813 936-2397and outstanding traditional Saturday night International Crystal Manufacturing Co 20Continued page 41supper serve Well year 43 Pattern N Lee Oklahoma City OK 7310212 Sport Scale contestants delighted share boiled shrimp steamed crab supper Crescent City Radio Control Club members secret out other crashed airplanes cant repaired just well dont some give try certainly beats starting scratch way Ive often remarked annual New Orleans contest best kept secrets South because ofoccasional spirse PC Boards John R Lange 1700 N 37th Ave Stone Park IL 60165Ron Van Putie Ill Sleepy Oaks Rd Fr Walton Beach FL 32548 RC Giant Scale/Beckman Continued page 43 conversation Dave Scully Aero Compo sites 411 Townsend Place Dayton OH 45431 mentioned quarter-scale kit Hal Krierversion Great Lakes Special kit almost unknown dont really push said would send some information busy before got Ive busy havent done anything until now meantime saw Dave Toledo chance see plane fuselage comes kit fiberglass fuselage/foam wing kit too common Giant Scale fuselage has stringer detail molded cap strips wing foam before covering wind up realistic looking construction model designed prop drive setup originally has since changed Quadra significant improvement performance Daves picture-taking technique worth comment dont know other way vuure going get kind siew Giant Scale aircraft inside house Continued page 114 February 1982111 John Lange poseswith models frontot car isequipped listen current RC frequencies through car radio professional microwave technician John has made use RC frequency monitoring gear work well