Stan, KM6XZ, wrote: The best fidelity I have in a communications receiver is a little DC receiver with a good balanced detector. Despite having no selectivity or features, listening to QRM and noise on that one with headphones is quite pleasant and the lack of IMD allows the brain to focus on one of the many signals in its bandpass with ease and lack of fatigue. That is an interesting experience and does show that noisy bands and raw signals are in some manner a high enough quality signal source if the receiver does not introduce too much IMD and artifacts. How to accomplish that with the added requirement of selectivity is the question...
By the way, just to start an argument....Ask an Italian or American who invented radio and the answer will be the same. But wrong, that honor does and should go to A.C. Popov... ---------------------------------------------------------------------------- I've had the same experience with DC receivers. The artifacts caused by non-linearity in the system generating more signals through the interaction of the signals being received is extremely subtle but most annoying when one compares it to a really clean receiver like a good DC. Some of the racket comes from the filters, since they introduce non-linearity by their very action. While there are many advantages to high selectivity, there are also serious disadvantages too! You can blame the "media" for any claim that Marconi "invented" radio. He never said that any more than the owners of the Titanic said it was "unsinkable". Both misstatements came from the desire of others for short, attention-getting headlines. Perhaps Marconi's greatest achievement was the long, hard effort to build a successful world-wide communications company that made his name a household word throughout much of the world and which put the advantages of radio communications to work for so many people. It's unlikely anyone would have survived the Titanic disaster without radio. Since the meaning of her flares were not understood by the ship who saw them, the only effective call for help was by the Marconi set. Marconi is, to me, the epitome of the old saying, "Your ideas don't work unless you do." Of course that's true of all great people. Ron AC7AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
