Radio Technique
REMEMBER that radio frequency interference (RFI) strikes without warning, and the results can be catastrophic. When it strikes, people send me letters and phone calls from all over the United States, either because I am chairman of the AMA Frequency Committee, or because I write this column. Most of the complaints are about: 1) Performance of new radios which is poorer than expected; or 2) Interference with operations on the new RC channels (Obviously, part of the increase in the number of complaints can be explained by the fact that the number of people using new radios on the new channels has increased. But I didn't expect to see such a high percentage of complaints about the next item.); or 3) Unexplained interferences between radios on the new RC channels.
Radio Technique
20 Jan 1985 Mr. George M. Myers AMA Dist. #2 Frequency Coordinator Dear Mr. Myers This note is to bring to your attention a situation in which you might take an interest. During May and June of 1984, I experienced severe interference problems on three different occasions, while using RC44 in western NY. I was flying a brandnew, seven-channel Airtronics Championship Series FM transmitter and receiver. Here's a description of the incidents: 1. Flying at Grand Island, about five miles north of Buffalo. Severe interference produced a crash. (At the time, I was not convinced of the interference, as the plane was new and not yet trimmed.)
WRAM Show 1985: New Beginnings
I WENT TO THIS SHOW looking for narrow-band dual-conversion receivers. We have needed them ever since the new RC channels were authorized, and the only ones to hit the market so far have been the Novak NER-91 AM and the Kraft KPR-8FD and FDS models. The Kraft synthesized receiver had some teething problems, which seem to have been taken care of. The big question now: "What is Kraft up to?" The company didn't show up at White Plains, so I couldn't ask the question. All I can report is that Kraft must still be making FDS receivers, because I traveled to the show with my friend, Norm Rosenstock, who received a new one in the mail a few days earlier. I looked at it, and it looks exactly like my old one. We haven't opened it up to look for the new dual-gate MOSFET, but I'll bet it's in there!
Radio Technique
INTERFERENCE TESTS. This morning, I received in the mail copies of correspondence between Mr. Geoffrey E. Styles, Director of Public Relations at AMA HQ, and Mr. George M. Weigman, Secretary of the Lake Shore RC Club (in Illinois). The gist of it is that members of the Lake Shore RC Club cooperated in an attempt to discover the minimum spacing between two RC fields-that is, minimum for their situation. A test plan was written and tests were executed using standard RC equipment, a CB for communication, and an automobile for distance measurement. The test airplanes orbited the Lake Shore RC Club field at various altitudes from 400 to 1,500 feet (we presume that there are no airfields for man-carrying aircraft nearby), and deliberate attempts were made to interfere, using same-channel transmitters at specified distances.
Radio Technique
"Dear George: " . . . I am especially interested in ultra-miniature RC. The problem is to find a source of ultra-miniature equipment. Remember the Albin Superregen receiver (May 1968 AAM)? I built one for an .010 aircraft, using MS76 Silver Oxide batteries and a Bentert Actuator and never did get consistent enough control to be happy, but the receiver only weighed six and the actuator 6.5 grams. Surely, there have been advances in the state of the art, but I haven't found them. Can you help? My goal is CO-2-powered Peanut Scale RC. I'll keep you posted when I put it all together. Thanks."
