[Elecraft] Frequency Counter

[Ron D'Eau Claire]

I have a little portable counter (ancient - late 70's technology) that uses
a 4 MHz crystal. It was nothing fancy. It didn't even have a way to adjust
the crystal frequency.  I had to add a small piston trimmer cap to the
design. I used it commercially to confirm that shipboard transmitters were
in spec before the FCC checked them during the annual inspection. I noted
that my counter was always very, very close to the FCC examiner's much more
sophisticated instrument. 

Mine used the common 4 MHz crystal. Before going out to a ship the check the
transmitters I'd set it using the 5th harmonic of the xtal to beat against
WWV. I could easily set it to with 1/2 Hz at 20 MHz. That is the S-meter on
the receiver monitoring WWV would wander every so slowly, completing a cycle
in no less than 1 second. That meant the time base error was 1/5 that for a
total error of 1/10 Hz or less. 

If I ever have to retire my little counter I'll look for a similar
capability in any design I use to replace it. As long as I can check the
calibration regularly I'll know how much a counter tends to drift and I can
quickly set it very accurately whenever I need to make an especially precise
adjustment. It's pretty rare when WWV isn't booming in here on 20 MHz on the
west coast. 

I set my K2's calibration using the procedure Wayne provided on the web
site, primarily because I wanted to see how easily it worked. It was simple,
quick and yielded results well within the 20 Hz or so possible error of the
DAC's used in the K2. So I never tried using WWV at 20 MHz to zero beat the
K2 control board oscillator, but I'd expect it to work just as well. 

After all, the K2 has a built in frequency counter. It's that built-in
counter's time base that C22 adjusts! Why not set it as accurately as
possible and use it as it was intended. 

Ron AC7AC