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 _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
