The band select oscillators are supposed to be locked to the 20 MHz
reference oscillator. In that case changes from band to band in offset from
correct frequency could only occur if the reference oscillator is not
correct. And then the differences would be due to the different
multiplication factors used to lock the different band select oscillators
to the reference.
It is not necessary to adjust the BFO oscillators before or after the
master reference oscillator. There are preferred orders to adjusting the
various BFO frequencies, since they interact with each other. The BFOs are
independent of the reference oscillator. They are not locked to anything.
There may be a convenient method of adjusting the reference oscillator that
requires the BFO to be correct first, such as listening to WWV or counting
the transmit frequency, instead of directly counting the reference
oscillator frequency.
Having said all of that, which I believe to be accurate in theory, I have
never been able to get my Omni VI to have correct frequency readout on all
bands to the accuracy I get on a Kenwood TS-440. But then the 440 has much
worse phase noise.
DE N6KB
DE N6KB
On Mon, May 7, 2018 at 7:56 AM, Gary Hendricks <k4mt1950@charter.net> wrote:
> I see this beat to death here but I have a question about peculiarities on
> this radio.
>
> I have seen to adj the BFO first and MO last. I have a very accurate HP
> counter referenced to 10 MHz stnd. Als a HP sig genrator.
>
> I find if I set BFO freqs to within 1 HZ that unless MO is adjusted off of
> exact 20 MHz the radio is off freq on all bands. To get it on freq after
> aligning BFO I must tweak the MO away from 20 MHz to end up on freq. I
> have always found MO freq wg=hen set dead on with other radios and BFO set
> correct the radio was on freq. Guess I am asking too much from this radio
> design.
>
> I remember seeing this on a corsair also years ago. I also seem to see a
> difference between TX and RX freq. Also the freq error changes from band
> to band I suppose caused by errors in the crystals for each band.
>
> I tried setting MO for exact TX freq but then BFO had to be altered to get
> RX freq right. Seems like chasing a moving target.
>
>
> Gary K4MT
>
>
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