[Elecraft] K3 filter problems

[Matt Zilmer]

All,

The 400 Hz and 1 KHz filters are 8 pole.  The offsets (should) be
zero.

matt

On Sun, 23 Nov 2008 18:23:12 -0800, you wrote:

>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: elecraft-bounces at mailman.qth.net
>[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jim Hoge
>Sent: Sunday, November 23, 2008 2:40 PM
>To: elecraft at mailman.qth.net
>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
>
>