I've seen a number of old U.S. broadcast receivers with a 10 KHz notch filter in the audio to get rid of the high pitched hetrodynes from the adjacent channels. But the wide IF sure brightens up the music when listening to your local honky-tonk station, and nobody gave a rip how wide their IF was if their music sounded good. That's why I was hoping for the option of going as wide as I see fit when conditions allow. But then who (other than yours truly) would be using a K3 to listen to the local BC when he could be working CW while enjoying 100 Hz selectivity?
Dave W5DHM > > > The basic reason has already been explained, however, there are very few > cases were exceeding 3kHz audio bandwidth is useful. HF broadcast > stations use 5kHz channelling, which would only allow them 2.5kHz with > brick wall filtering at both transmit and receive ends, although they > probably do expect to suffer significant adjacent channel interference. > > MF broadcast stations use 9kHz channelling in Europe and 10kHz in the > USA, but I suspect that adjacent channel interference is less > acceptable. As they were designed to be received with LC IF filters, > with poor shape factors, I suspect they don't even make use of the full > channel, and if they did, they would probably be required to have > filters which put the adjacent channel into the filter stop band. > ... > David Woolley _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
