Posted by
Don Wilhelm-3 on
Mar 21, 2007; 12:58am
URL: http://elecraft.85.s1.nabble.com/Zero-beat-WWV-tp444945p444946.html
Dave,
If you have WWV properly tuned at 9999.99 (when in SSB mode), that is
only 10 Hz off frequency, and is well within the range of error to be
expected with the K2. The digital quantizing error is about 20 Hz.
The K2 always displays the frequency of the carrier - so when tuned
properly to WWV, you will hear (or see on Spectrogram) the tones
demodulated (as you have done), but when switching to CW, you should
hear the carrier at the pitch you have set for the sidetone.
When listening to WWV in CW mode it is easy to mistake one of the tones
they transmit for the carrier. At the times they transmit a 600 Hz
tone, you will be able to hear discrete signals at 9999.40, 10,000.00
and 10,000.60 since it is an AM signal transmitting a 600 Hz tone. (You
can hear one signal at the carrier minus the transmitted tone pitch, the
carrier itself, and another signal at the carrier plus the tone pitch.)
If the CW filter is narrow enough, you will hear each of these signals
as separate signals in the receiver - you must be careful to identify
the actual carrier. Using the wrong one will create a large apparent
error in your dial readout. It is best to tune WWV during the minutes
they do not transmit a tone - tune the carrier to your sidetone pitch
and the dial should read correctly.
Just adjust the CW BFOs so the passband is centered at your chosen
sidetone pitch (using a noise input, NOT a single signal) - and set the
dial calibration in LSB or USB, then believe that the K2 will take care
of the offset for you. On CW, the dial readout will be the carrier
frequency of the station you are listening to and will also be the
frequency you will transmit on.
73,
Don W3FPR
David Wilburn wrote:
> I have setup Spectogram, and have 500 & 600 Hz markers setup. I then
> set the K2 to 10000.00, in U mode, and adjust the frequency until I have
> either 500 or 600 Hz depending on which minute it is (odd minutes being
> a 600 Hz tone and even being a 500 Hz tone, even though this seems
> backwards of how it should be).
>
> I then used this zero beat reference, and the procedure on page 101 of
> the K2 manual so that I have it down to U or L mode is zero beat at
> 9999.99.
>
> I notice the calibration on page 101 of the K2 manual says to use U or L
> mode. My question, is how much should the offset be when I go to CW
> mode? I am trying to track down why my CW RX frequency is so far from
> my USB frequency (was 1500 Hz off at one point). I have it better, but I
> am sure the issue is with how I did the alignments.
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