[Elecraft] Calibration of BFO

[Rich Lentz]

Tom, Dave, Elecraft group;

Thanks for the help.  Like you said, it's a matter of trial and error.  And
sometimes all it was was making sure that each filter got reset in memory
and not just the one that seemed out of whack with the rest.  Took about
another hour tonight, but I think I got it as close as is possible.

On lower bands (below the reversal of BFO shift) got the following results
reading the frequency off of the MIXW 2 display.  (Seems to provide a finer
resolution than Spectrogram.)


	FL1	FL2	FL3	FL4

USB   REF	-4	-6	-10
LSB	REF	0.0	0.0	0.0
CW	REF	-5	-5	-5
CWR	REF	-7	-7	-7

USB, CW, and CWR all seem to provide absolutely no change in pitch (Using
750 Hz) Listening to a steady carrier on the air with RF gain and ATT set so
that it is just audible and at normal listing level.  Will probably play
some more over the weekend (After I write down all the numbers.) and see if
it possible to get closer.

Messing around with PSK, It looks to me as there is no reason not to use LSB
(on the lower bands), especially if you intend on dropping to a narrow
filter.

>
>I have found that you can get the shift reduced to less than 1 Hz by just
>repeating the procedure numerous times. Sometimes by just adjusting one
>filter at a time.  Often I just go in to the procedure and just the BFO by
>one 'notch' and back again and exit, so it will recalculate the offset.  I
>have been able to get it down to the point where there is no audible pitch
>change (musicians ear) between the filter settings, and just a slight
>phase twist on the PSK tuning eye.
>
>It WILL drive you nuts, but it can be much better than 10 - 20 Hz.