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WWV tones and CW reverse?

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JAKidz

WWV tones and CW reverse?

Holiday Greetings:
When a K2 is set to zerobeat the 10 Mhz WWV carrier, should the
pitch of the WWV tones not change when toggling between CW and CW
reverse in CW mode or between USB and LSB as toggled by CW reverse? And,
when the pitch does not change, the difference between the frequency
readout (10000.14) and 10000.00 is how much lower I need to set C22?

Thanks,
John, K7JG.

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Don Wilhelm-3

Re: WWV tones and CW reverse?

John,

The 'proper' answer depends on what you consider 'zero-beat' to be. In CW
mode, you would want to hear the WWV carrier at your chosen sidetone pitch
for a real 'zero-beat' setting - AND the displayed frequency will be offset
by the sidetone pitch amount.

If you are using SSB, there is no offset, but in SSB mode, zero beat will
be heard with the carrier at zero frequency (which neither your ears or the
K2 audio can hear).

I believe it is better and easier to listen for the 500 and 600 Hz tones
transmitted by WWV to assure exact zero beat. I use Spectrogram to tell me
when I have tuned correctly to zero WWV - the displayed peak will be either
at 500 or 600 Hz depending on which minute it is (can you tell I don't have
the gift of perfect pitch? <G>).

Take a look at the K2 dial calibration article on my website
www.qsl.net/w3fpr for more detailed information on setting the reference
oscillator.

73,
Don W3FPR

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

> Holiday Greetings:
> When a K2 is set to zerobeat the 10 Mhz WWV carrier, should the
> pitch of the WWV tones not change when toggling between CW and CW
> reverse in CW mode or between USB and LSB as toggled by CW reverse? And,
> when the pitch does not change, the difference between the frequency
> readout (10000.14) and 10000.00 is how much lower I need to set C22?
>
> Thanks,
> John, K7JG.
>

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Bill Coleman-2

Re: WWV tones and CW reverse?

In reply to this post by JAKidz

On Dec 26, 2004, at 9:13 PM, JAKidz wrote:

> When a K2 is set to zerobeat the 10 Mhz WWV carrier, should the
> pitch of the WWV tones not change when toggling between CW and CW
> reverse in CW mode or between USB and LSB as toggled by CW reverse?

There may be a slight change. It is hard to eliminate this entirely.

> And,
> when the pitch does not change, the difference between the frequency
> readout (10000.14) and 10000.00 is how much lower I need to set C22?

I believe this is entirely dependent on the BFO settings for CW and CW
R (or USB and LSB).

This is one of my tricks for trying to get USB and LSB to sound the
same. (and for CW and CW R) I'll use another receiver to listen to a
strong AM signal (with an AM detector). Then I'll tune the K2 with LSB
until it sounds the same pitch, and switch to USB. If there is a
difference in sound, I bump the USB BFO setting one notch either way
until it is the same. (This is done after calibrating with Spectrogram
or its equivalent) Usually the initial calibration is close, but this
helps to get it dead on (well, at least really close).

Note that, because of the asymmetrical shape of the SSB filter (and to
a lessor extent, the CW filter, depending on how wide it is set), the
"color" of the background noise in USB and LSB will be different, even
when the BFOs are dead on.

Because of the slight variability in frequency steps in the K2, the
frequency response in each sideband can be off by about 20 Hz.

I've never understood the obsession with exact frequency readouts with
the K2. Even if you get C22 exactly on 4.0 MHz, the K2 calibration may
vary a bit. If you are within 200 Hz on all bands, I wouldn't worry
about it.

Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901

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Don Wilhelm-3

Re: WWV tones and CW reverse?

Bill,

200 Hz calibration error is quite a bit IMHO - but each to his own.
Just so folks don't develop a wrong impression, I usually expect less than
50 Hz error with nothing more than a quick check of the 4 MHz reference by
comparing the TP3 output using an external counter and the internal CAL FCTR
(both measuring the TP3 frequency)- just turn the capacitor until both
counter read the same.

Then after everything is built, I fine tune using the N6KR method with
Spectrogram as my guide to properly hearing the 500 and 600 Hz tones that
WWV transmits. I expect less than 20 Hz error after completing that (if
your results are not that good, my first question is 'Did you do CAL PLL and
also run CAL FIL to write new BFO values?, and were you certain of WWV
zero-beat?'

73,
Don W3FPR

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

>
> I've never understood the obsession with exact frequency readouts with the
> K2. Even if you get C22 exactly on 4.0 MHz, the K2 calibration may vary a
> bit. If you are within 200 Hz on all bands, I wouldn't worry about it.
>
>
> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
> Quote: "Not within a thousand years will man ever fly!"
> -- Wilbur Wright, 1901
>