ken.d.brown at hawaiiantel.net
Tue Jul 5 21:00:58 PDT 2011
Keith Hamilton wrote:
> I hear the default 700 Hz tone thru the 500hz filter with the band pass control centered. When I switch to the 250 Hz filter the tone remains 700 Hz The signal strength goes to almost 0. To bring the signal strength back, I must tune up the band raising the tone heard at the same time to an unacceptably high level This should not happen if the passband of the two filters is the same.
Or you could adjust the PBT while leaving everything else alone. The
tone frequency will remain the same and you should be able to find a PBT
setting that maximizes the amplitude of the signal producing the 700 Hz
A firmware and hardware upgrade to the Omni VI could have a setting for
the PBT changed by the 6.3 MHz filter selection. This would require that
the microprocessor have control of the 15.3 MHz VCXO in the PBT system,
which it does not have.
Another upgrade I dream about (which is just as unlikely to ever become
a reality) is for the microprocessor to have control over the BFO
frequency. Not just five choices, but actual control. This would allow,
with the right firmware, an adjustable sidetone that coincides with the
signals that pass through the 9 MHz IF filter. There would be no need to
have "high note" and "low note" and RTTY narrow filters of all the same
bandwidth with different center frequencies.
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