Posted by
Edward R Cole on
Oct 21, 2018; 8:13pm
URL: http://elecraft.85.s1.nabble.com/K3EXREF-issue-K3-tp7645822p7645852.html
Gary,
Well first thing I would check is whether 10-MHz is present at the K3
EXREF sma jack. If you have a freq counter check for correct
freq. No counter then use a radio that can tune 10-MHz for presence
of signal on correct freq.
Check for adequate reference level (I run 10mw which is more than
adequate; probably will run with 3mw to 5mw). If you have no
milliwatt meter then use an oscilloscope to measure RF voltage. Pav
= Vrms^2/R or Vrms = 0.3535*Vp-p*probe multiplier.
From:
http://www.ab4oj.com/test/pwrmeas.htmlPav = 10*10^-3 = 0.01 w , Vrms = sqrt(Pav*R) = 0.707v, Vp-p = 2,.828*Vrms = 2v
If you are using a 10x probe Vp-p = 0.2v; Be sure to measure voltage
across 50-ohm load connected to the REF input.
If this is low or nonexistent try a different cable from the
GPSDO. Also check 10-MHz output at the GPSDO.
My guess either you have no 10-MHz ref signal or its off
frequency. If that is good then recheck configuration to enable
EXREF. Still bad: then check internal coax from EXREF connector to syn board.
73, Ed - KL7UW
http://www.kl7uw.comDubus-NA Business mail:
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