My first guess is that the crystal oscillator on the XTAL OSC.-L.O.
MIXER BOARD is not properly locking to the reference oscillator on the
LOGIC BOARD. If that is the case, then the problem may go away, or at
least change a bit on different bands.
Instability of any of the oscillators would cause a warbling sound.
Oscillators that are part of a phase locked loop are probably more
likely to have that sort of problem than ones which operate independently.
To test whether it is the BFO, try listening to CW using USB. A
different crystal and trimmer capacitor are used, so if the warbling
goes away suspect the BFO parts used for CW and LSB receive.
If you have another receiver you could try tuning in to the various
oscillator frequencies used inside the Omni VI to see which ones are
stable and which ones warble. You might hear some of them with an
antenna in the shack, but more likely will need to use some sort of
pickup loop or probe inside the Omni VI to receive them.
Listen to the 20 MHz reference oscillator, or the 10 MHz product from
it. Is it rock solid or warbling? Listen to the BFO at 9 to 9.003 MHz.
Listen to the XTAl OSC which operates at different frequencies depending
on what band the radio is on.
Eventually you should be able to determine where the instability
originates.
DE N6KB
DENNIS BRICKEY wrote:
>
> Good evening,
>
>
>
> I have an Omni VI Option 1. I had the radio checked and aligned
>
> just a little over a year ago. When I got it home, I made a hand full
>
> of contacts and put it in its box. I got it out this weekend, and is
>
> an issue with CW receive. The CW audio sounds like it is
>
> warbling, like the cw note is unstable. I left it on all weekend, but
>
> there has been no change. Just wondering, short of another trip to
>
> the mothership, if anyone has a suggestion for where to look and
>
> what to look for. I have no instruments for troubleshooting, but I
>
> could possible check some simple items.
>
>
>
> If anyone can offer advice, please respond direct, and off line. I do
>
> not want to tie up the reflector.
>
>
>
> Thanks in advance for any help.
>
>
>
> 73,,
> Dennis
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> TenTec@contesting.com
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