The K3 is capable of displaying frequencies to 1 Hz. It can be calibrated to somewhat less than 1 Hz against WWV (method 2).
Because I wanted to see if my K3 serial 1322 was capable of measuring frequency to its displayed precision, I decided to attempt the November 11/12 ARRL Frequency Measuring Test. I warmed up my K3 for about two hours because--even with the optional TCXO--my K3 drifts almost 0.1 ppm per degree Centigrade from 25C to 30C, the latter part of its warmup range this time of year at my QTH. (0.1 ppm is almost 1 Hz on 40 meters.) Then I carefully used method 2 to calibrate against 10 MHz WWV, checking after exiting REF CAL by tuning across WWV on CW with SPOT activated to see that the beat notes were similar on each side of zero beat for 1 and 2 Hz off frequency. (A lack of similarity indicates that a small tweak of REF CAL is needed.) Tuning past WWV's carrier on CW with SPOT enabled also provides practice for the real thing. When W1AW (and each of the other FMT stations) began its call-up, I tuned its frequency to be centered in the passband with the DSP set at 50 Hz bandwidth. When the long dashes began, I turned on SPOT and zero-beated against the sidetone with 1 Hz fine tuning. After recording the result, I moved on to the other frequencies and stations that had been specified in the ARRL FMT announcement. I was able to copy and measure 4 of the 5 tests, with one station on one frequency being inaudible at my QTH. Result: my K3 was within 1 Hz on all 4 readings, that is, its accuracy matched its displayed precision--after warmup and careful calibration. 73, Paul W8TM ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
