Whenever you reduce the bandwidth, you restrict all the audio you hear to that bandwidth. Make the filter narrow enough, and the only sound you hear will be one tone, and it won't go on and off any more than the tone of a bell does (i.e. it rings like crazy).
There is no "magic" solution to that - restrict the bandwidth and you stretch the dits and dahs of CW out over time. It's all a matter of filter sharpness or "Q". Okay, with that background (forgive me if it's very old news to you, Jim), 1 kHz isn't very narrow. So what could be producing a narrower bandwidth? My first thought is that you're crystal filter (the roofing filter) is not centered on the DSP filter bandwidth, so the effective bandwidth is much narrower than 1 kHz. If you used the 5-pole filters, did you input the offsets for the 1K and 400 Hz filers correctly (including the minus sign ahead of the offset)? If not, you might have just part of the filter bandpass reaching the DSP, producing a total bandpass only a fraction of 1 kHz. Ron AC7AC From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Hoge Sent: Sunday, November 23, 2008 2:40 PM To: [email protected] Subject: [Elecraft] K3 filter problems Greetings, I seem to have a problem with either how I set up my K3 or with the filters. When first built the radio, I had only the stock 2.7 filter in it. I noticed that the receive audio began to ring and sound hollow when the bandwidth was reduced to about 1K. I now have the 1K filter in position 3 and the 400Hz filter in position 4. (I may add a narrow phone filter in the future in position 2.) Filter widths are configured at 1K and 400 respectively. All filters are enabled for both cw and digital. I note that the filter in use does coincide with selected bandwidth but again, as I narrow down to 1K or tighter, the received sound is still hollow and ringy. BTW, only the 400 Hz filter has gain added in the configure menu to offset its loss. Have I done something wrong? Tnx, Jim W5QM #1816
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