[Elecraft] To PLL mod or not
[email protected]
[email protected]
Mon Nov 11 17:13:15 2002
Bob, N6WG wrote:
"If you are looking at a received signal or marker with Spectrogram,
center the signal in your narrowest passband.
If the vfo is stable and the BFO is drifting, the signal should stay put
within the passband (determined only by vfo and filter) but the pitch
should change.
If the vfo is drifting, the signal will move in the passband and the
pitch will change.
This should allow you to determine whether vfo or BFO is drifting."
==========
A much easier way to see if you have BFO drift is to set up Spectrogram
with a marker at the sidetone pitch you selected via the ST P menu.
Then select your narrowest CW filter and look at the spectrogram display
on just noise (no signal!).
If the BFO is set up properly (CAL FIL), the marker will be in the center
of the filter passband.
If BFO temperature drift occurs, you will see the passband move up or
down in frequency on the Spectrogram display (resulting in the sidetone
pitch marker no longer being centered in the passband).
73, de Earl, K6SE