[amsat-bb] RE: Drake 2880 conversion crystal

[Ed Krome <71611.76@xxxxxxxxxxxxxx>]

I've had a few questions on what kind of crystal to use to convert the
Drake 2880 to a 70cm IF. Because the LO multipllies by 256, a
microprocessor crystal of 7.68 MHz will give a 1966.080 MHz LO. Since the
2880's normal IF is pretty close to 70cm, no IF mods are required (though
they won't hurt).

Suitable crystals are Mouser 520-HCA768-20 (HC-49/U can; it's too tall for
the enclosure so it has to be laid down some when installed) and Mouser
520-HCU768-20, which is a very short HC-49/US and fits fine. It costs a
massive $1.12.

If the frequency conversion is a little strange (2401 MHz RF ~ 434.92 IF),
who cares? Doppler and yet-unknown final satellite LO frequencies will mess
nice even conversions up anyway.

Enjoy,

Ed Krome K9EK
(No, this conversion isn't in "Mode S: The Book", but lots of other stuff
is... call AMSAT for a copy.)
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