Leigh, WA5ZNU asked: Although that isn't strictly the BFO setting, if you center the wider filters around the CW pitch and it is too low, won't their skirts extend below 0Hz and pass the opposite sideband?
---------------------------------- True, but that's not a selectivity issue. A 2 KHz filter that is positioned to pass both sidebands is still has a bandwidth of 2 KHz. It's selectivity is unchanged. If the filter is narrow enough and positioned in the right way with respect to the signal frequency, you'll only hear one sideband. That's why us "graybeards" call "single signal selectivity" or adequate selectivity to suppress the "other" signal or sideband. Nowadays I've noticed that a lot of younger operators think "single signal" means sharp enough selectivity to hear only one signal on the band at a time, but that's not the original definition at all. It simply meant that the selectivity was good enough so that when one tuned across a CW signal, that signal was only heard once (only one sideband in the bandpass). Ron AC7AC _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
