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VintageViews A


s the result of my recent columns about R/C in the early ’50s, Patrick Broderick of Santa Rosa, CA sent me a September 1951 is-


sue of QST. QST is still published by the American Radio Relay League, Inc. The ARRL is a noncommercial association of ra- dio amateurs, bonded for the promotion of interest in amateur radio communication and experimentation, for relaying of mes- sages by radio, for the advancement of the radio art and the public welfare. The ARRL was formed in 1914. Of particular interest in this issue is an


article by Walter Good and William Good entitled “Receivers for Radio-Controlled Models—Features and Comparisons of Lightweight Units”. I’ll mention a few com- ments from the article that I found very in- teresting. “The airborne receiver undoubtedly offers


the most fascination of any part of the radio- controlled model aircraft. The extreme em- phasis on light weight, including batteries, immediately eliminates superhet receivers, heater-type tubes, and other heavy ap- proaches. As a result of the severe require- ments, all of today’s receivers are of the su- per-regenerative type, and most of these have been optimized in a direction usually


by bob noll You can reach Bob Nollvia e-mail at bobrc@aol.com


not considered for communication. That is, they are designed to give the maximum plate-current change upon receipt of a car- rier signal.” Walt and Bill continue their article by dis- cussing four distinct types of receivers in- cluding their relative merits. Here are a few of their comments: “The lightest weight single-channel re-


ceiver is that using the subminiature RK61 gas tube…. The principle disadvantages of the gas tube are its short life (3 to 100 hours) and the variable adjustments needed during its gradual deterioration. “The second type of receiver uses a vacu-


um triode and a quench-oscillator coil. The main advantage of this receiver is its long life and reliability…. Adjustment of anten- na length to give proper loading for best re- sults is somewhat critical and is considered a disadvantage. “The third type of receiver is an unusual combination of both the R/C ‘squegging’ and the LC ‘quench’ oscillators. This type is mar- keted by Vern McNabb as the first radio con- trol equipment on the 465 Mc citizen’s band. Its disadvantage is the need for more batteries. “The fourth receiver is a three-tube mod- el. It has one super-regenerative stage, one


voltage amplifier stage and one power am- plifier stage. Reports indicate excellent reli- ability with the only real disadvantage be- ing the weight of the receiver and batteries compared to other sets.” The authors stated that the receiver de-


sign is still the weakest in the radio control system. This is scary but I still remember my first


Esco Lorenze receiver that used the infa- mous RK61 tube which I operated from my Gyro ground base transmitter. As a con- trast, this past winter I had some fun con- verting a single channel F&M ECHO trans- mitter to 2.4 GHz using a FrSKY module and Phil Green’s Single Channel Encoder. What a comparison in size, weight and reli- ability. This configuration lets you be a but- ton pusher with a FrSKY modern receiver operating regular servos as if you had a com- pound escapement in the plane. Remember one for right, two for left and


three for up elevator with quick blip for three-position throttle. Before my next col- umn I expect to have flown this system in my deBolt Champ. Getting the proper set- ting for medium throttle will be the greatest challenge and Phil’s encoder is programma- ble for this purpose. Here’s hoping my thumb doesn’t do any “dumb thumb” things!


PHOTOGRAPHY: BOB NOLL


This F&M single-channel transmitter (at left) was converted to 2.4 GHz with the help of a FrSKY module and a Phil Green single-channel encoder. This setup allows a modern receiver to operate with modern servos as a compound escapement. See text. Dave Dow and his scratchbuilt Taurus(above) as seen at the VR/CS Northwest Fly-In in Medford, Oregon.


56 AUGUST 2012


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