Don...
Bingo! The F4 filter setting was too narrow, as you advised. Also, the
BFO was somewhere off from where it belonged. Once I got those two item
adjusted everything worked as per specs. I was impressed that the BFO
values that you quoted were more or less right on. Seems like you have
some experience with the K2 :-). Thanks much for your time and
attention, as always. Have a good day.
...robert
On 4/11/2019 14:00, Don Wilhelm wrote:
Richard,
Try widening the FL4 filter out to 0.2 instead of 0.1. With the more
narrow setting there is often more attenuation with little actual
reduction in width.
When aligning the BFOs, pay attention to the DAC values (and/or
frequencies). The ones for CW must be less than the filter center and
those for CWrev must be greater than the filter center. Normally the CW
FL4 will have a BFO frequency near 4913.12 and for CWrev a frequency
near 4914.3 kHz.
Make certain when aligning the filters with Spectrogram you use a source
of wideband noise. If you are using 'antenna noise', be certain there
are no signals nearby.
73,
Don W3FPR
On 4/10/2019 9:28 PM, Robert G Strickland via Elecraft wrote:
I have aligned my K2 crystal filters with Spectogram many times, but
this time I've run into a problem that I can't figure out.
Using Don's [and the manual's] instructions, I can align F1,F2,F3 in
decreasing bandwidths. All works as per expectations. On F4, the
alignment goes "ok," [as per Spectogram] but when I use it with
on-the-air signals, the signal "disappears" and shows up about 900 cps
lower and in "reverse" orientation [BFO on opposite side]. When the
signal disappears, I can change filters [F1/F2/F3] and it's right
there where it should be with the bandwidth getting narrower as
expected. But, switching to F4, it's gone. I have tried changing the
BFO frequency throughout its whole range when in F4, thinking that
I've aligned it on the "wrong" side. No luck. I'm stumped. Any and all
suggestions welcomed.
--
Robert G Strickland, PhD ABPH - KE2WY
[email protected]
Syracuse, New York, USA
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