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RE: Mode U/S passband frequency alignment



Leland C Scott said:

> I noticed I was off about 15KHz from
> where I expected to be based on my
> up-link frequency and Doppler, which
> should have been less than 1 KHz at
> the time per WinOrbit.

...

> I don't expect it to be nowhere as
> great as the 15 KHz or so

Hello Leland

Your downconverter can quite easily be 15kHz off. True you can calibrate it
but don't expect miracles. The TCXO will need to warm up for several minutes
too.

The only way I've been able to home in on my downlink straight off every
time has been to use InstantTrack/InstantTune with a calibrated and
warmed-up downconverter. Even then there's some tweaking of a few hundred Hz
to be done. It's wise to use a wider SSB filter rather than a narrow CW
filter during this phase or you'll easily miss yourself.

73 Howard G6LVB

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