[Elecraft] Another K@ frequency calibration technique

[Ron D'Eau Claire]

A similar procedure that I've passed on to a number of ops with success =
uses
the harmonics of the signals derived from the 4. Mhz clock.=20


Tune in WWV at 10 or 20 MHz and zero beat the carrier with the SPOT
function, just like tuning in any CW signal as Glen described. Lock the
tuning so you won't "bump" it.=20

Replaced the antenna by a test lead and touch the other end to the can =
of
the 4 MHz oscillator crystal. A loud fifth harmonic of the oscillator =
will
be heard if the rig is tuned to 20 MHz or a weaker harmonic of one of =
the
"counted-down" products of the oscillator will be heard if the rig tuned =
to
WWV at 10 MHz.=20

Check to see that you are hearing the 4 MHz oscillator on the control =
board
by touching C22 and verifying that the frequency shifts.=20

(If you have the KPA100 operating, it's 4 MHz clock may be interfering =
with
you. If so adjust it to a higher frequency. Elecraft recommends this to =
keep
it from interfering with signals at the top of the 75 meter band. The
frequency of the 4 MHz clock in the KPA100 is not critical and has no =
effect
on any calibration).=20

Adjust C22 so the signal is zero beat with the SPOT tone again and you =
are
done.

Of course, CAL PLL must be run again and the system forced to re-read =
all of
the CAL FIL BFO frequencies before the change takes effect.=20

As Glen points out, you can't get any closer than this. It doesn't =
matter if
you can't get the 4 MHz oscillator exactly zero beat with the SPOT, =
since
you are using a harmonic anyway. A 10 Hz at 20 MHz is actually only a 2 =
Hz
error at 4 MHz, for example.=20

Ron AC7AC
K2 # 1289