[Elecraft] K2 Frequency accuracy by band

[Don Wilhelm]

Jeff,

You should be able to achieve +/- 30 Hz on 10 meters with a bit of care and
patience.

The most accurate method I have found for setting the reference oscillator
frequency prior to doing a calibration run with the K2 is the 'N6KR'
method - it uses WWV tuning as the only variable external to the K2 and to
that extent is 'self-calibrating'.  Most other methods introduce other
pieces of equipment each having their own potential calibration errors -
which Murphy says will usually add to give the worst possible result <G>.

It usually takes me 2 runs through the procedure to 'get it right' - but the
results are worth the effort IMHO.  The really hard part is making certain
you are zero beat with WWV, and I observe the 500 and 600 tones on the
Spectrogram display to be certain I am really zeroed - another 'quirk' is
that the K2 shifts frequency just a bit when going into CAL FCTR mode, so
you need to compensate so that WWV is zeroed AFTER setting the K2 to CAL
FCTR - it may take a few practice trials to get it that way - patience is a
virtue (so they say - whomever THEY may be <G>)

Take a look at the K2 dial calibration article on my website
www.qsl.net/w3fpr for more information.  Note well - you MUST do the whole
thing - CAL PLL and CAL FIL both before drawing any conclusions about the
resultant accuracy.

73,
Don W3FPR

"Life is what is happening when you are making other plans" -- Mike Cross

----- Original Message ----- 
From: <jeff_elecraft at burnshome.org>
To: <elecraft at mailman.qth.net>
Sent: Thursday, June 03, 2004 10:59 PM
Subject: [Elecraft] K2 Frequency accuracy by band


>
> I borrowed an IFR FM/AM-1200s service monitor from a friend for a project
I
> was working on. While I had it I decided to check the frequency accuracy
of
> my radios. I thought my K2 was 60 Hz high and quick check confirmed this.
>
> I then used the service monitor to adjust the 4MHz crystal, and ran CAL
PLL.
>
> I checked the frequency accuracy on each band using the following
procedure.
> I set the frequency on the service monitor to the center of each band, and
> injected that signal into the radio. In CW mode I used the spot tone to
> match the incoming signal as close as possible. I then transmitted a low
> power signal back into the service monitor, and adjusted the transmit
> frequency until the frequency deviation meter indicated zero deviation.
The
> difference of the service monitor setting and the radio frequency display
> was then noted.
>
> The results were:
>
> Set Freq. (MHz)   Error (Hz)
>         1.9       -10
>         3.75 -10
>         7.15 -30
>        10.1       -40
>        14.15 -60
>        21.2      -110
>        24.93     -130
>        28.5      -140
>
> Testing to WWV at 10MHz gave a +10 Hz error. Testing to WWV at 15MHz gave
an
> error of -10 Hz. These do not quite agree with the test using the service
> monitor.
>
> Has anyone else measured the frequency deviation of a K2 per band? Are
these
> errors normal?
>
> I also ran this test on my Omni VI. This brings up another question that I
> will pose in a separate message.
>
> By the way, my friend used this service monitor professionally, but has
not
> had it calibrated since he retired more than ten years ago.
>
> Jeff Burns
> AD9T
>
>
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