[Elecraft] N6KR's 4 MHz oscillator cal method for the K2

[Don Wilhelm]

Fran and all,

Switching modes after tuning in your signal (WWV usually) can result in
errors.  A change in modes (or sideband) will switch to a different BFO
frequency, will erase all that careful tuning that you just did - unless
both BFOs are set at the same frequency (not likely unless you took care to
make them that way beforehand).

See my additional comments below ---

73,
Don W3FPR

----- Original Message ----- 
|
| My normal method for WWV is to use the spot tone.  This can be more
| difficult with the 600 Hz tone being audible so I often switch to my
| narrowest filter.  Since this has been described many times in many ways I
| will not repeat one here.  I learned the process from the K2 manual
though.

COMMENT:   If you set your sidetone pitch to either 500 or 600 Hz, you can
beat the SPOT signal with the demodulated WWV tones - just be certain that
you know which one you are trying to beat with because they alternate each
minute.  See the WWV schedule at
http://www.boulder.nist.gov/timefreq/stations/iform.html.
|
| For Waynes procedure I then switched to OPT1 in LSB and things sounded
right
| so I went on with the adjustment from there.

COMMENT: 'Sounds right' can be better determined by also listening to WWV on
an AM receiver should you have one available - of course for those who have
the gift of perfect pitch, they will have no problem detecting when the
tones are 500 or 600 Hz (or 440 Hz at 2 minutes after the hour).

|
| Somebody else had earlier suggested finding zero-beat in CW and switching
to
| LSB also.

COMMENT:  Just do the zero-beat in CW (match carrier with your spot tone)
but do NOT switch to LSB, move right on to adjust C22 with the CW BFO active
(STAY IN CW mode).

| Another method would be to find the 600Hz carrier in CW using spectrogram
| and then switching to LSB and making sure things are still well centered.

COMMENT:  While I think it easier to use Spectrogram to tell me the tone
pitch, if you are tuning in CW mode, look for the carrier at your sidetone
pitch (ignore any tones that WWV is transmitting).  Again, switching after
you have carefully zeroed the signal will change BFOs - the results will be
in error (unless both BFOs happen to be on the same frequency).
|
| All this greatly depends upon how well aligned the filters are to one
| another.  Same goes for switching between LSB and USB for same sound.  It
| only works when well adjusted.
|
| Fran
|