The technique using WWV is more than good enough if you keep one thing in mind.
The mater osc referenced to the crystal osc is the source for the HFOm IFLO and BFO
so they all move if the master OSC? moves.
IF you do the cal you may have to move the other two to have it all line up.? however
In my heart 30hz is not a significant error.? Must have been awful for those guys using?
old school VFOs with dials calibrated to 1khz.? ;)? ? Then again I manage to talk to people
with my Tempo-one (old school analog tube).
I use a crystal source (20mhz) that's dialed into WWV 30 years ago and checked as
a very accurate source.? That is all and then go through the process.
I do it on receive. just as accurate ans the RX and tX should be the same.
For 20MHz source, set RX for 1khz tone (20.001 or 19.999 depending on selected sideband).
Use counter to measure tone out of the RX (1000.0 hz).? For the 5351 based systems I set the?
correction for the crystal osc by measuring the the its highest frequency output first with a
counter and make that correction as others have noted.? Then I only need to touch up the BFO
so its at the right point on the filter slope. at that point if there is error if the control has the
option I correct the IF offset.? Over all I do it 2 or three times for high accuracy or call it good
enough.? Usually if its it is within about 10hz or less and that better than most radios out there
I stop there.
For frequency stability its all tied to the 25mhz osc and that is usually 20 or 50ppm part?
over the temperature range so over time It drifts a few Hz to aging and the rest is
temperature.? For room temp plus or minus less than 10C change its a small error
and a generally reproducable one.
Allison
