From: Rick Eckel <[EMAIL PROTECTED]> But how about if all the other conversations are being held above 20khz or below 20hz??
Does sheer power on other frequencies swamp the front end of a receiver? Shouldn't we see more evidence of this at the launch area? =========================== Up or down 20 khz doesn't mean anything if the desensing happens in a stage that lets through a range that's 1 mhz wide. And that is indeed the case for r/c receivers, the front end lets through every signal on the whole 72 mhz band. If an unwanted signal is 60 db above the desired signal, it can impair the receiver's ability to respond to the desired signal. And of course the IF of a little r/c radio doesn't have a lot of selectivity either. What Randy experienced wouldn't happen at the launch area, because all the signals are strong. But in Randy's case, his signal was weak because his plane was low and far away from his transmitter, and the other guy's transmitter was right under the plane. The effect of such desensing is the same whether the desired signal is PPM or PCM, but a PCM radio might have saved him via the fail-safe feature. The plane might have continued on its course until the desired signal reappeared in the passband. RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
