[Elecraft] Calibration of BFO

[Dave Gingrich K9DC]

At 07:28 2/4/2002 -0600, Tom Hammond N=D8SS wrote:

>Consider NOT using the OP1 filter for PSK31. You can set the other three=20
>filters FL2 thru FL4 to wide mid and narrow bandwidths as well...=20
>possibly, you can find settings which don't shift using strictly the CW=20
>filters.

Only problem is OP1 is always used on transmit so you need to minmize the=20
shift between OP1 and the chosen receive filter, even if you never use OP1=
=20
to receive.

>Note that it is NOT at all unusual to have a 10Hz - 20Hz frequency shift=20
>when switching between filters. If you managed to get it down to 0Hz=20
>shift, it was almost a fluke.

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

It WILL drive you nuts, but it can be much better than 10 - 20 Hz.

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Dave Gingrich, K9DC - Indianapolis, Indiana  USA
K2 #2211, K1 #931, QRP-L #2376, ARS #1109,
FPQRP #389, IRLP #473, k9dc.ampr.org, CCIE #6748
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