On April 24, 2006 01:56 pm, Matt Osborn wrote: > WWV provides a BCD subcarrier at 100Hz that is always present. Using > HRD's PSK31 (it's free; thanks Simon!) it is a simple matter to adjust > the tuning to the proper frequency.
Please expand on this. I have never used a PSK application, but how would it detect the subcarrier is exactly at 100 Hz? I suspect the software is using the soundcard clock as a reference and that wouldn't necessarily be very accurate. Seems that the K2 can be set very exactly using Wayne's method (http://www.elecraft.com/Apps/K2%20C22%20Adjust%20App%20Note.pdf) but it requires properly zero beating WWV. Using an audio spectrum analyzer such as Spectrogram to detect WWV's broadcast tones is dependant on the accuracy of the spectrum analyzer. The spot tone generator in the K2 seems to derive it's clock and therefore it's frequency from the MCU and the 4.0 MHz oscillator set by C22, so the spot tone frequency will be dependant on the setting of C22, which is what we are trying to set in the first place. So using this tone as a reference does not look like it will work. Having a calibrated audio spectrum analyzer may be one solution. Perhaps a musical tuning fork via a microphone could be used to calibrate the audio spectrum analyzer. How accurate are tuning forks? Wayne suggests just listening for zero beat, one should be able to get within about 15 Hz. The trick seems to be how to tune the K2 to exactly 10,000.000 kHz and at the next step up of the vfo be at 10,000.010 kHz. Seems a lot like an ARRL frequency measuring contest. :-) What tricks have others on the list found to tune WWV to within 1 Hz or less without expensive professionally calibrated test equipment? 73, Darrell VA7TO K2#5093 -- Darrell Bellerive Amateur Radio Stations VA7TO and VE7CLA Grand Forks, British Columbia, Canada _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
