[Elecraft] [Elecraft K3] Frequency Calibration using Sidetone

[Ron D'Eau Claire]

Scott, what's the advantage of your iterative process over simply setting
the K3's VFO on freq (e.g. 10.000000 MHz) and then tuning for zero beat
using REF CAL as described in Method 2? 

Ron AC7AC

-----Original Message-----

My procedure is only a slight modification of Method 2 in the manual.  The
AGC will keep the audio level nearly constant under all but the worst
conditions.   


1.  Select fine VFO resolution (1 Hz).

2.  Select CW mode, fast AGC, and set bandwidth to 500 Hz.  (You don't have
to have a CW xtal filter.)

3.  If using WWV, do the calibration only when the carrier is unmodulated.
If you try it when there are audio tones, you may end up tuning to one of
the sidebands.

4.  Using CWT, tune to the calibration signal.  This will get you very close
to zero beat.

5.  Locate CONFIG:REF CAL.

6.  Tap SPOT to enable the sidetone, and adjust its level to be about the
same as that of the signal.  You should hear the "beat", a fluctuation in
volume.   If necessary, adjust the sidetone level for the strongest beat.
(If you can't hear it when adjusting the sidetone level, shift the VFO a few
Hz.)  Tune the VFO for the slowest possible fluctuation, probably less than
1 per second.  If you have trouble hearing the fluctuations, try feeding the
audio to an analog voltmeter or oscilloscope.

7.  Note the VFO display frequency. If it isn't within about 100 Hz of the
calibration signal, adjust the REF CAL frequency in small increments, always
retuning the VFO for zero beat as above, until the VFO display reads with
100 Hz of the calibration frequency.  Once you get within about 100 Hz, set
the VFO for exactly the calibration frequency, and adjust REF CAL for zero
beat as above.  (You may be close enough initially.)

8.  Using the K3 utility, save the configuration.  (Or record the REF CAL
value.)

9.  Cancel SPOT and exit the menu.


73,

Scott  K9MA