Having done some long term measurements on my k3extref using an HP mHz resolution counter i have seen no corrections during transmit. Once the k3 has "warmed up" (first thing in the morning it would take 10 minutes for the original tcxo to stabilise enough for jt65/wspr/qrss(5Hz fsk)) I see very few corrections being made on receive either.
All I need now is the release of the internal 144 xverter and I am good, frequency stability wise thro 76GHz Dave ww2r ------------------------------ Message: 44 Date: Wed, 6 Apr 2011 00:58:58 -0700 (PDT) From: "Julian, G4ILO" <[email protected]> Subject: Re: [Elecraft] K3EXREF and Trimble Thunderbolts To: [email protected] Message-ID: <[email protected]> Content-Type: text/plain; charset=us-ascii Don. WSPR is AFSK with a very small shift at a very low rate. My thinking is that if a stepwise frequency correction was made during a transmit or receive period, it would cause a corresponding shift of the VFO which might be enough to throw the decoder of the receiver. I don't know, that's why I was asking. K2ULR has told me off-list that he did not believe corrections are made while the K3 is transmitting. But it might still affect receiving. I think it is important to know because WSPR is one of those modes where frequency accuracy is really helpful and habitual users of the mode will probably be interested in the K3EXREF. Don Wilhelm-4 wrote: > > Julian, > > Please explain why you think any vfo tuning "steps" are related to a > frequency shift induced from the audio input to the K3. I believe this > is mixing two entirely separate parameters. > > I have not actually operated WSPR, but it cannot be that difficult (nor > that precise in practice). I believe one would use DATA A sub-mode for > WSPR work. > > The VFO places the waterfall within 1 Hz of the desired fequency with > the external reference (actually that could be within 50 Hz - same > argument). Now the software applying the audio to the K3 has to shift > 1.5 Hz (or 170 Hz for that matter), As long as the K3 can tune the > desired frequency to be in the passband, the software and audio input to > the K3 will take care of the audio shift. The only requirement is that > the K3 remain frequency stable once the frequency is selected - the rest > is done in the computer application software. > > 73, > Don W3FPR > > ----- Julian, G4ILO. K2 #392 K3 #222. * G4ILO's Shack - http://www.g4ilo.com * KComm - http://www.g4ilo.com/kcomm.html * KTune - http://www.g4ilo.com/ktune.html -- View this message in context: http://elecraft.365791.n2.nabble.com/K3EXREF-and-Trimble-Thunderbolts-tp6242 158p6245052.html Sent from the Elecraft mailing list archive at Nabble.com. ------------------------------ _______________________________________________ Elecraft mailing list Post to: [email protected] http://mailman.qth.net/mailman/listinfo/elecraft You must be a subscriber to post. Elecraft web page: http://www.elecraft.com End of Elecraft Digest, Vol 84, Issue 8 *************************************** ______________________________________________________________ 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
