Keith, KD1E wrote: When I had narrow filtering in my Omni V I found that S/N did not increase as bandwidth decreased. Instead, the noise began to sound like signal since both were at the same frequency. Add some filter ringing to the mix and sometimes the narrowest settings made copy worse.
As always, I reserve the right to change my mind as I get more operating time with various rigs :-) ------------------------------- I, too, have had Keith's experience. Over the years I use narrow filters ONLY when absolutely needed to remove extremely loud QRM. Most often I listen to CW using my >2 kHz OPT1 filter. Perhaps it's a result of having learned to listen to CW as an SWL and Novice many years ago using regenerative receivers and simple superhets for which 6 to 8 kHz bandwidths were typical. And the CW bands were a lot more crowded then, typically, than today. That doesn't mean that I didn't have exotic filters. The most exotic filter yet developed is the one between our ears. It has to be trained, however. For speech, we do that instinctively from childhood by listening. Who hasn't picked out a single voice across the room at a crowded party and heard every word in spite of a dozen or more other voices also carrying on at the same time. It only gets really hard when some character starts shouting in our ear so we can't hear the other voice through the hubbub. We can learn to do the same with CW. Of course, the first step is to avoid having the signal we want to hear made quieter, which is why I avoid AGC for most listening. It responds to the aggregate of signals in the bandpass. I want it to leave my volume where I set it. With most receivers I like having a hard limiter that doesn't let any signal exceed a certain threshold regardless without affecting the other signals. I've never fashioned one for my K2 because I haven't found that the K2 seems to need it. Very, very rarely do I find the copy better at narrower bandwidths for just the reason Keith observes: the narrower bandwidths tend to concentrate all the energy in the bandpass of the filter. It's like trying to listen to someone in a crowded room when a whole group of people are talking at about the same volume, with the same basic pitch to their voices, with similar inflections and pace to their speech (the bane of the keyer!!). Another advantage of using wide bandwidths is being aware of what's going on around the frequency too. Unless the other station is really whizzing along requiring my full attention to avoid missing words, I can keep track of several QSO's around the frequency, again just like being a party. One doesn't have to catch every word to have a good sense of what's being said here and there while still paying quite close attention to the person I'm talking with. It's something that almost anyone can learn with practice. And you already own the filter! 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
