Mike, I was one of the beta-testers of the K3EXREF and see about a move from 49.380 to 49.380.080 over about an hour from cold start. Then is settles down to moving only in single digit amounts. MY 10-MHz reference is a surplus OCXO (oven controlled xtal osc) rated at +/- 5 E-12 which holds the K3 to within +/- 2 Hz at 28-MHz. The error is proportional to frequency so error is < 1Hz at 20m and below. On 6m it runs between 2-Hz and 3-Hz error measured on my mw frequency counter locked to a Rubidium standard. You can view my complete beta-test report on the EXREF at: http://www.kl7uw.com/K3EXREF.htm ---------------- Date: Sun, 29 Apr 2012 06:58:42 -0700 From: Matt Zilmer <mzil...@verizon.net> Subject: Re: [Elecraft] K3 Frequency Shift To: Mike Harris <mike.har...@cwimail.fk> Cc: elecraft@mailman.qth.net Message-ID: <62iqp7l39asr4eh8abo3h36g64m6q5u...@4ax.com> Content-Type: text/plain; charset=ISO-8859-1
>It would be interesting if someone with an EXTREF board installed would >post the change in REF CAL number from cold to hot and extended run. For K3 #24, w/EXTREF: Cold start: 49.379.774 is typical; After ~2 hours warmiing up: 49.379.693 is typical. The EXTREF here is driven by a Trimble Thunderbolt-based GPSDO. 73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 50-1.1kw?, 144-1.4kw, 432-QRT, 1296-?, 3400-? DUBUS Magazine USA Rep dubus...@gmail.com "Kits made by KL7UW" http://www.kl7uw.com/kits.htm ====================================== ______________________________________________________________ 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
