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Re: K2's 4 MHZ Master Oscillator.

Posted by Earl W Cunningham on Sep 02, 2005; 2:14am
URL: http://elecraft.85.s1.nabble.com/K2-s-4-MHZ-Master-Oscillator-tp381793p381794.html

Bob, WB8DDI wrote:

"I used Wayne Burdick's article to calibrate my K2. When I first tuned in
WWV, the zero beat was at 9999.5. I adjusted c22 & measured  TP1(VCO) &
TP2(BFO) until the two test points matched. Now WWV zero beats at
10000.5."
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500 Hz is a big error.  You can get it much closer.
==========

"Should I have set my dial to 10000.00 & then adjusted C22?."
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No!  Nothing will change until you do a CAL PLL after adjusting C22.
==========
There are a number of methods of getting the 4000 kHz xtal oscillator on
frequency by adjusting C22.  Without a frequency counter, one of the
easiest is to tune in 20 MHz WWV on your IC-756Pro.  Use a short piece of
flexible insulated wire for the antenna on the 756Pro and bring the end
of that antenna near the 4 MHz oscillator in the K2.  You'll hear the 5th
harmonic of the 4 MHZ oscillator beating with WWV (best to use the AM
mode on the 756Pro and wait for those times when WWV is not transmitting
a tone).  When you hear the heterodyne beat between the 5th harmonic of
the K2's 4 MHz oscillator and 20 MHz WWV, adjust C22 to zero beat the
heterodyne.

Anytime you adjust C22, you must follow with a CAL PLL.  Then check your
K2's frequency dial readout  accuracy.

73, de Earl, K6SE
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