[Elecraft] Problems because of filter switch during CW operationK2

[W3FPR - Don Wilhelm]

Steve and all,

I beg to differ - for 2 reasons

First, centering a 1.5 kHz bandpass on 600 Hz will result in the passband
lapping over into the opposite sideband by 150 Hz.  A preferred method is to
set the 700 Hz filter first (centered on 600 Hz) and then observe where the
left edge of the filter bandpass falls on the Spectrogram display (put the
mouse pointer on the filter slope and clicking will leave a red crosshair
marker) - after that, go to the wider filter and change the BFO so that the
left edge of that filter is positioned the same as it is for the 700 Hz
filter (position the filter so the slope falls on the red crosshair marker).

Secondly, the K2 firmware actually works to preserve the pitch of a signal,
and as long as the signal falls anywhere within the passband of the filter,
the pitch will not change - of course there is digital quantizing error to
contend with in the K2, so you may find a pitch change of up to 20 Hz, and
that is not unusual.

73,
Don W3FPR

> -----Original Message-----
>
> If your narrow filters are aligned using the Spectrogram software so
> that they are all centered on your cw tone (say 600 Hz), then all you
> need is to zero beat the signal while in the 1.5 kHz filter, and then it
> will stay centered even at 100 Hz.  The instructions for finding and
> using Spectrogram are on the Elecraft site.
>

--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.323 / Virus Database: 267.7.3/15 - Release Date: 6/14/2005