Bill W5WVO wrote
I work 6-meter WSJT digital modes, where frequency differences measured in Hz are significant. Working with various other stations whose technical capabilities I trust more then my own, I've concluded that my K3 is about 96 Hz, plus or minus, on the low side of actual when the VFO is set to a kHz integer frequency on 6 meters. (E.g: display frequency 50260.000, actual frequency 50259.904.) I would like to tweak this in to a higher degree of accuracy. Since I didn't put together my own K3, I'm not at all sure how to do this. Can someone knowledgeable point me in the right direction? If test equipment is needed, let me know what it is.
The reference oscillator calibration procedure is described on page 49 of the manual. You don't need any special test equipment. You just need to be able to receive a signal of known accuracy.
There are various ways to do this, and if you can receive WWV then you can probably use that. What I did is tune a short wave broadcast station 1KHz high or low in SSB mode and then adjust the reference oscillator so the heterodyne was precisely 1KHz, using the sound card software Fldigi to measure it. If you have a frequecy counter that measures audio frequencies you could feed the audio from the K3 into that, I suppose.
Most short wave broadcasters are accurate enough on frequency for our purposes, but it makes sense to tune in several and check the heterodyne is the same pitch, to avoid picking one that is off-frequency.
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