[Elecraft] K3EXREF issue? K3

[Edward R Cole]

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.html
Pav = 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.com
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