[aprssig] HF APRS Transceiver

Ev Tupis w2ev at yahoo.com
Fri Mar 7 17:14:48 EST 2008

--- Ben Jackson <ben at ben.com> wrote:
> Crystal control is not sufficient.  20ppm at 10MHz
> is 200Hz which is an order of magnitude or more too
> high (consider that the shift of the FSK is only
> 200Hz).  You probably need around 1ppm accuracy.
> The operator-free solution is a reference clock
> slaved to the GPS.  With DDS it shouldn't be that
> hard.

On 10 meters AX.25 can be 1200 baud.  200hz there is
fine.  Having a monoband transceiver for that would be
great (though there are still HTX-10's and -100's on

I'd buy for PSK31 use on other bands (where 200 hz is
again insignificant, given the passband/waterfall is
so broad).

Ev, W2EV

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