Hi Tom: Very true. And, another factor is that most FM receiver IF circuits run the circuit gain at maximum. The resultant signal becomes distorted, but only in the sense that amplitude variations are totally removed. No matter, of course, since you want to detect the - frequency- variations (it's FM, after all). So, without using a squelch circuit to mute the audio, it's going to sound much louder.
In fact, most squelch circuits use that broad-band noise to determine that a signal is -not- on the frequency. When a signal shows up, the receiver's AGC will detect that and turn the max gain down. The difference in levels between the empty frequency and one with a user on it, "opens" the squelch, and then you hear the station. When the incoming station is "full quieting"... it's signal is so strong that the IF gain is pushed down so much that the detected audio is "quiet".. i.e. no additional band noise.. just the clean audio to your speaker. Same deal with FM broadcast receivers. 73 de Ray K2ULR On Nov 25, 2011, at 3:12 AM, [email protected] wrote: > > Yes, that is normal. When you switch to FM you are listening to a > much wider > portion of the band you are on. > > 73, > Tom > Amateur Radio Operator N5GE > ARRL Lifetime Member > QCWA Lifetime Member 35102 > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
