HOWARD W. ASHCRAFT, Jr. W1WF wrote: Last night I redid my C22 reference oscillator adjustment using WWV on 10mhz as the zero beat reference. This is the third time I have adjusted C22 and each time I am able to adjust C22 to a precise offset balancing TP1 and TP2. However, when I put the cover back on the K2/100 I find that WWV zero beats a few tens of hz off. (After last night's adjustment, the zero beat was 10000.03) One should expect to be +- 10 hz as that is the finest resolution of the VCO, but it would be nice to get a little closer. --------------------------------------
You are probably fighting the resolution limits of the digital-to-analog converters (DAC's) used to convert between the analog tuning voltages for the BFO and PLL reference oscillator and the digital values stored in memory. Since they convert the analog voltage into a binary number, and use that binary number to recreate the voltage later as you tune in a signal and choose the filter setting you want, they are never exact. Sometimes one is closer than 10 or 20 Hz, sometimes not. At that level it's a matter of "luck". That's the source of often hearing a small step in the frequency of a CW beat note when switching between filters too. 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
