Adding to Ron's, ZL1TW, comments about Wayne's N6KR excellent method to set
the 4Mhz oscillator using WWV/WWVH or similar reference source:-
I have always found it easier to Zero beat using CW spot and the beat note
between the WWVH and the spot Tone. However YOU MUST remember to switch the
mode back to LSB BEFORE proceeding with changing C22 otherwise your dial
will be nicely offset by your sidetone frequency.
There are slight dial setting differences of a few 10s of hz if I zero beat
WWVH using the different filter settings (CW normal). Using CW reverse also
can change the dial reading for a zero beat slightly too. Because of
this, I always zero beat with the mode set to CW normal and the 700hz
filter, this being the filter I mostly use.
Another slight source of error is the thermal drift between when you zero
beat to WWV/WWVH and the time it takes to get C22 adjusted for both
frequency readings to be different by the appropriate amount. My K2
drifts down in frequency from cold to warm so when I take the top off the K2
to connect the probes to adjust C22 it moves up slightly in frequency as it
cools slightly. I usually set the final zero beat dial setting 10hz below
the actual zero beat point to compensate for this.
YMMV
73, Nigel ZL2DF
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