Jim Harris wrote: > 1. Recently I've noticed when it is initially turned > on the received frequency is about 100 hz high judged > by the pitch of people's voices that I know. After > 20-30 minutes they drift to near exact frequency.
And Bill, AA4LR replied: I had this sort of problem before I installed the PLL and BFO stability mods. Your K2 may be recent enough to have come with these modifications. -------------------------------- Bill offers excellent comments and replies. I happened to turn my K2 on early today to check WWV at 10 MHz. Within a minute of turning it on, I was listening to WWV and the dial read 40 Hz high: 10000.04. (See below* for my method of finding Zero Beat in SSB mode if you're curious) A half hour later zero beat was exactly at 10000.00 kHz I just checked it now, about 11 hours later and it's still at 10000.00 kHz I've found that typical since adding the BFO and PLL Reference Oscillator (L.O.) stability mods. It isn't always 10,000.00 kHz, but within 10 or 20 Hz of the right frequency. If you're seeing a 100 Hz shift, I suspect you're missing one or the other of the two oscillator mods - perhaps both. The rigs varied a lot before the changes were made. Ron AC7AC *SSB "Zero Beat": Tune in WWV in either upper or lower sideband mode so it sounds "close" then press/hold CW RV to change instantly to the other sideband. (That button works in SSB as well as CW). If you aren't exactly on frequency, you'll hear the pitch of the tone jump up or down. Tune in 10 Hz steps until you hear the direction of the jump change. For example, when I switch from L to H, I may hear the tone go up in pitch. So I increment the frequency 10 Hz higher, then switch from L to H again. If the pitch goes even higher, I went the wrong way, so I tune 20 Hz lower. Change from L to H again and see if the tone goes up or down. Now it should definitely go down. Tune down another 10 Hz and switch from L to H again. Keep this up until suddenly the tone jumps up instead of down in pitch. That means that I just passed the optimum tuning point. Either zero beat was the last 10 Hz point or it's between 10 Hz points. Note that every time I switch sidebands the SAME direction: L or low to H or high. You can go either way, just make sure you switch back before checking at the next frequency! You don't have to match tones. You only need to be able to tell that the tone shifted direction and whether it went up or down. _______________________________________________ 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
