[hpsdr] FMT differences between Magister and Metis

[Ken]

> >>
> >> Perhaps those playing with FMT can provide some insight as to tricks
> >> they do with the HPSDR to minimize error.  I was thinking of trying
> >> to use ghpsdr3 running multiple receivers.  Have a couple receivers
> >> locked to different WWV frequencies and one measuring the unknown
> >> frequency.  This might allow one to zero out apparent frequency
> >> changes due to the Doppler effect.
> >>
> >> 73 de WY3D
> >> Ron

Ron -
Because of the size of the tuning word and they way it is used in Mercury,
you will see a pseudo random tuning error of up to about 30 milli-hertz. For
example, when you are tuned to 10 MHz you are really on 9999999.984741

Changing the interface between Ozy and Metis should not affect this (I
hope!).  

A few frequencies come out exact - just by coincidence.  I have a
spreadsheet that shows how to do this - I will send you by direct mail.

Measuring WWV with ionospheric propagation is a real crap shoot. You can get
nearly 1 Hz Doppler at times.   2.5 MHz is usually not affected by Doppler.
Happily, one of the magic frequencies for Mercury is 2.499 MHz.  Tune your
Mercury there and you will hear a 1000.000 Hz beat note, if your Excalibur
and Thunderbolt are working properly. 

Ken
KE2N