OK, how do I find out if I need this mod? I have witnessed two different frequency shift problems, one of them I have posted here and there has been some discussion about it.
Problem #1 (posted before) -- when listening to CW, when the signal is reasonably strong such as S9 or better, if there is a slight pause in the sending there is sometimes a frequency shift on the order of 10 Hz to 40 Hz. I am guessing at the actual shift amount as it is a slight but very apparent shift in tone. Problem #2: on a couple of occasions while operating PSK, there has been a slight shift in frequency, enough that my software is no longer tracking the signal (I use CocoaModem). I am not sure how much a shift would need to be for CocoaModem to lose sync but it does lose sync. This has happened a few times. At first, I thought it was the other guy hitting his VFO or maybe some old tube rig that is has an unstable VFO but the last two times it happened I am pretty sure that it was me (and, my hands are no where near the VFO knob). By the way, as far as I know, in neither case above, does the VFO frequency readout change value. For PSK, I keep my VFO pegged on 14070.150 Hz and I think I would notice if this changed. 73, phil, K7PEH On May 27, 2010, at 3:54 PM, Bruce Beford wrote: > The app note for modifying the K3SYN board has been posted to the K3 > Enhamcements and Application Notes page at: > > http://www.elecraft.com/K3/k3_app_notes.htm > > It is a simple one-resistor mod. Next time I have the rig open, I'll > probably do both of mine. > > Description: > "In rare cases, at certain frequencies the DDS driving signal to the Phase > Locked Loop (PLL) may be marginal, resulting in a sudden shift in frequency > (commonly called "chirp"). This modification adds a resistor to the KSYN3 > board that increases the DDS drive level prevent this condition. " > > "This is an optional modification and is not required unless you are > experiencing this condition." > > 73, > Bruce N1RX > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
