Dave, It hadn't occurred to me that frequency correction would be suspended in Tx. That is both good and bad, as I see it. Good that no phase jumps occur, but bad that transmitter drift is not being corrected.
For eme digital modes this means the freq. is solely held by the TCXO over the minute-long transmit sequence. That probably will not affect the K3 when running transverters as there will be no large thermal change in the radio operating at mw levels. It may see more effect when I run HF/6m at 12w on my K3/10, but that probably is much less than those that run the K3/100. I guess I will have to reserve judgement on how well K3EXREF will assist operating at microwaves (mw). As I see it now, the K3EXREF will track out mid-term frequency drift of the TCXO during receive sequences, so the Tx drift (if any) is limited to that which occurs in 1-minute. Transmitting on CW/SSB is not as exacting on frequency accuracy so not likely the user will notice a few Hz drift, if it occurs. Even used with mw transverters, frequency error remains the same as the IF error since it is translated in mixing and not multiplied. Where it would be significant is if the K3 were used RF source in a Multiplier chain to produce a mw CW signal. I am not familiar with what method is favored for mw >24 GHz I see REF CAL offsets being applied consistently for the first 30-min after K3 power-on. Maybe my TCXO has aged more in the first year of use? I saw only 14-Hz freq. error on 28-MHz last fall, while it shows about 36-Hz error on 28-MHz, now. This is with no REF CAL adjustments or K3EXREF running. Once K3EXREF is initiated 28-MHz remains within 1 to 2 Hz on my counter. I will have to monitor 2m when I next run eme to see what happens. 73, Ed - KL7UW ------------------------------ Message: 5 Date: Wed, 6 Apr 2011 07:47:02 -0500 From: "Dave" <elecr...@g4fre.com> Subject: Re: [Elecraft] (no subject) To: <elecraft@mailman.qth.net> Message-ID: <pheojohbikmljjhhfcgfkeamebaa.elecr...@g4fre.com> Content-Type: text/plain; charset="us-ascii" 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 73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubus...@hotmail.com ====================================== ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
