When dealing with very weak signals in the absence of really strong QRM, I use the widest bandwidth possible for just that reason. At least 2.8 kHz is typical for me and I almost never drop below 1 kHz. The more pink or white-ish the noise, the easier it is to hear a very weak CW signal down in it.
That's why I vastly prefer the notch filter to help my gray matter filter in case a really strong signal appears in the bandpass. On stronger signals mixed in a lot of heavy QRM I'll crank in the bandwidth so the desired signal is the only one I hear. Then I can pretend I'm listening to a code practice oscillator - it sure doesn't sound like a "radio", Hi Now that Wayne's implementing APF I'm curious to see how it sounds. I'm prepared to be astonished if it sounds any different than a decent active audio filter with some gain at the center frequency. Ron AC7AC -----Original Message----- On 10/25/2010 12:29 PM, Merv Schweigert wrote: > but never found them useful for CW. The filter in my head always seems better at picking out the desired signal than the audio filter That's usually been my experience too, primarily because the skirts ring on QRN, and the narrower the filter, the closer those skirts get to the CW note. The closer the ringing is to the CW note, the harder it is for the ear/brain to separate them. This is pretty well known by scientists working in the psychoacoustic world. 73, Jim K9YC ______________________________________________________________ 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
