Posted by
Bill Coleman-2 on
Jan 22, 2005; 5:27pm
URL: http://elecraft.85.s1.nabble.com/WWV-tones-and-CW-reverse-tp372927p372928.html
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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