d loec ni ue George M Myers ANOTHER EXCITING MONTH started phone call John Lange wanted know making out converter sent As showed last month proper way deal just about potential RC inter ference situation monitor RC hand simply isnt substitute know ing whats out John Lange' ask John Lange K9ARA 1700 N 37th Ave Stone Park IL 60165 AMAs DEC Large District Frequency Coordinator really no way can properly thank him reams data has sending past two years subject monitoring results has ob tained Chicaco area may call mind article Model Aviufion February 1982 ginning page 36 described build converter John offers printed circuit boards components completed converters various prices think best deal offers com pleted converter around S 100 use automobiles AM receiver because works well easy install gives information less cost can get scanner fixed channels primary disadvantage Johns sys tem von have sit ou get what pay scanning Either way John has converter use other-band scanners such offered Radio Shack want Con tact John address civen above Johns phone call set motion spent next week driving around Long Island NY purpose discussing performance new RC channels actually usine visited several tlying sites used con verter monitor 72 73 MHz band interferences Most folks using new RC channels having no trouble two notable exceptions report crash resulting intereference RC5O 72790 MHz Nassau County Model Aerodrome Cedar Creek Wantaugh NY probably re sulted very strong signal 72800 MHz pocket pager located top World Trade Center New York City already knew transmitter CompComm listing distributed AMA HQ District Frequency Coordinators warned clubs area poten tial problem hold office DFC District II well National Fre quency Committee Chairman get paper Unfortunately some folks dont join AMA clubs dont get word Anyhow got moni tor found signal advertised times stronger signals receiving RC transmitters guys flight line about 500 ft moni tor took ample demon stration potential interference fore leaving subject must point out signal question perfectly legal proper Rejecting can fly safely matter receiver design Ill have say later also report five crashes Saturday afternoon Whitman Flyers field Bethpage NY blamed inter38 Model Aviation AMA Frequency Committee chairman hard work sampling RC band aid Lange converter attached old AM car radio speaker mounted its rear cassette recorder lying dash allows George record overheard signals does understand later study analysis ference Since also serve Treasurer club thought might good idea some monitoring over too People have crashing RC airplanes years benefit interference Im sure know Still since monitor car wouldnt hurt check crashes 6-me ter band nothine pre pared about got field picked up pocket-pager transmit ter 72800 loud clear before Given no information receivers question Im prepared accept probable cause problems RC5O 72790 MHzonly 10 kH away RC52 72830 MHionly 30 kHz away reported might accept 'possible' explanation problem RC48 72750 MHzthough 50 kHz separation seems unlikely unless pager transmitter out adjustment timewhich can happen left crash 72240 Red White considered couldnt find interference channel time wao doing lnonibarim did find strong beacon signal some son 72280 possibility does exist receiver question couple years old might have gone through few crashes 'but still works' case real cause crash would have 'need re-tunine' Another equallyvalid possibility signal much stronger RC transmitters siiz nal would have interfered no matter much tuning done too would solvable receiver design Im about discuss THE KRAFT KPR-8FD RECEIVER certain excitement comes realize have piece future hands felt excitement after Bob Aberle concluded some testing prototypes KPR-8FD receiver receiver can buy year put service now keep using through 1991 go using 50 channels aircraft--and keep using throughout foreseeable future may remember showed photo receiver last month taken Kraft booth Weak Signals show Toledo Now Bob have couple field test report upon Its little early give full test results some preliminaries receiver true narrow-band design suitable use channels spaced 10 kHz apart what have con sider positions respect Com mon Carrier Personal Radio Service transmitters even-numbered frequen cies 7208 7224 etc Because dual conversion design immune image problems other RC transmitters various intermodulation prob continued page 139 September 1983 39 Bob Aberle R makes low flyby Grumman Kitten Sport Scale model equipped narrow-band Kratt KPR-8FD receiver prototype 4-man interference team tries shoot him down unsuccessfully simultaneous transmissions three nearby RC channels Bob flying RC52 72830 MHz others transmitting RC54 72870 MHz RC56 72910 MHz 72840 MHz special non-official channel 10 kHz away Bobs channel course interference team fingers poised transmitters power switches ready switch OFF first hint trouble photo taken telephoto lens Georges radio-controlled camera safety low camera angle telephoto distortion makes plane seem flying much higher actually interference team after successful day note smiles L H Ron Farkas George M Myers Tom Hunt Paul Bell Ralph Fisch Bob Aberle test subjects include Bobs Kraft Signature transmitter modules KPR-8FD receiver inside model Lest think Georges good friend Bob Aberle has doing ot test flying heres Georges Curare Pattern plane Guess what receiver uses Bob dont fly together though because theyre both same channel would believe nose gets too high tail waggles prototype vertical fin replaced larger swoopy-looking thing have learned stab wing blank out fin high angles tack produces fish tail about 50 side side everything under controL model isnt going drop wing snap-roll just waggles tail sassy sort wayand goes merry way Hurst Bowers upon learning models fish tailing wrote has built three different Luton Minors over years tail-waggle characteristic seems perfect example model duplicating idiosyn cracy full-sized aircraft cannot get model spin Throt tled way back dead-stick matter fully stalled aileron ele vator rudder can input just mushes off side drops nose repeats cycle model extremely stable Luton Minor size wing loading exceptionally easy model fly would nice RC trainers gentle Loops tend look like hen eggs Rolls Youve got kid ding Theonly roll doll can down runway So shes aerobatic glo riously cute air ground Placed half less throttle putts sputters around unbelievably slow speeds n delightful realistic manner long-term popularity Luton Minor sport fliers stems pure joy flying same holds true model Everyone flies Luton falls love must reason con stantly use feminine gender talking about means build yourself certain enjoy Radio Technique/Myers Continued paoe 39 lems have discussing past Better read last line again caught implication what youve read understand can tear up chart June 1983 column throw away Providing flying KPR-8FD receiver Nobody RC trans mitter likely get What about guy directly chan nel FM sets have property called Cap ture Ratio What means FM receiver tends keep listening its con trol transmitter until some another transmit ter same nearby frequency shows equal greater power capture ratio receiver pretty good ground bring another FM trans mitter same channel about half distance between control transmitter airplane before saw sign inter ference air tests did Bob Aberle flew plane front us swooping low pass about 10 ft altitude 20 ft out front us straight run about 500 ft beginning ending about 100 ft altitude stood about 20 ft behind him about 30 ft away direction plane going another Kraft FM transmitter same channel Bobs As started run turned transmitter ON planned keeping ready turn OFF instant saw sign interference plane came passed its way up out before got glitch repeated test three times sure what seeing would absolutely stupid put up two planes same frequency same time place test shows get lot protection effects guy might also flying channel some nearby field some test modules allowed us put up signals 10 20 30 40 kHz off Bobs channel RC52 might just well have left home effect also AM transmitters RC54 RC56 have poten tial produce detrimental third-order mix ing products talked about 3MPI June 1983 Radio Technique column almost waste time make test couldnt generate significant inter ference until stood both transmitters antennas fully extended right over airplane Incidentally going paging transmitter pumping out strong signal 72800 30 kHz Bobs RC52 checked monitor distance 500 ft park cars paging signal times stronger Bobs RC signal receiver designed built USA It will also available new Ham channels 5080-5098 MHz should very useful will need Amateur Technicians license fly AM FM anything Ham channels can use FM system new old 7273 MHz channels license whatsoever because noexamination CB license has elimi nated announced July AMA News page 105 ANOTHER RECEIVER Hold everything Just ready mail column Reston made acquaint ance Coulter Watt Whitestone NY Coulter has flying Ace Silver Seven-equipped Sagitta Syosset NY channel RC5O 72790 MHz having noticeable trouble monster 72800 Via Don Broggini learned after several weeks flying Coulter met first glitch low down far out about retune receiver offered retuning him could just assess present state tuning first arranged did found very little could improve factory tuning maybe 15% improvement SMASH SUCCESS TOLEDO! Thousands Already SOL D! 242 PAGES KITS/RADIOS ENGIN ES/ACCESSORIES TOOLS/SUPPLIES BOOKS/EQUIPMENT Major minor US Manufacturers represented entire product line Technical Descriptions & Prices Photos & Illustrations & Buy Hundreds Scratch Plans Model Aviation RCM & Others An Invaluable Source Book Products Beginner Expert See July 83 Model Aviation Product Review Guide Dealer Inquiries Welcome See Local Dealer Order Direct NAME ADDRESS Send check money order Consumers Guide Consumers Guide P0 Box 376 Greet FeiI VA 22066 Send SOSOllncludespoetegelhendfing3 Canadian Orders send $735 linciudes poe hand Oversees orders send $786 tincludes postlhendl MA September 1983 139 First Guide Devoted Exclusively R/C Aircraft
