[Elecraft] N0SS CW Filter Alignment

[Ron D'Eau Claire]

> I noticed that the 500 & 600
> hz tone markers don't line up exactly with the respective marks on the
> Spectrogram when I shift from usb to lsb or (cw & cw reverse) . In other
> words, if I put the tone on 500 hz on lower sideband then shift the K2 to
> upper sideband it is sort of close to 500 hz, if I try I can't get both on
> 500 hz . For instance on 10 mhz lower sidband displays 999982 & upper
> displays 999977.
> Ron N8SZY


As far as I can see, that is entirely "normal" for a K2. The i-f filter is
NOT symmetrical. That means that the slope of the lower frequency side of
the bandpass is NOT the same when shifting from upper to lower sideband.

If I set the filters to produce the same response on a DSB AM signal when
switching from upper to lower sideband, the BFO is way off from the right
setting for good signal quality. Indeed, I am rather disappointed in the
gradual slope on the lower sideband in any case. It produces fairly "muddy"
sounding audio compared to the upper sideband. Optimizing the BFO settings
to minimize this means that I must retune slightly when shifting between
upper and lower sideband. That's not an issue for me, since I don't normally
listen to double-sideband signals, Hi!

Ron AC7AC
K2 # 1289