[Elecraft] K3-Measuring Filter Offset

[Mike Scott]

>It's not unusual for the 8-pole filters to have small offsets, which would
be particularly noticeable if on the bass side of the >passband.  I've heard
of up to 80 Hz (0.08) in some CW filters.  Anything large than that,
indicates something else may be going >on (like accidentally resetting the
5-pole offset to zero as K7SV noted in the original post).

 

Could someone describe a procedure to measure filter offset. I have
spectragram (can't remember the real name) software on my PC.

 

I have a five pole 2.7 KHz in each of main and subreceiver. They are matched
to -0.87 but I would like to measure and split the difference if there is
one. I do notice that the main rx filter has enough of a passband slope that
USB and LSB frequency response is notably different. I can hear a
significant change to background noise color when I change modes. For this I
am hoping to have mode-specific equalization some day. It is also possible
that a different offset might improve what I am hearing.

 

Mike Scott

AE6WA Tarzana, CA

K3/100 SN508