Re: [amsat-bb] AO-40 Receive and FT-847 serial control

[Jim Sanford <wb4gcs@xxxxxxxxx>]

My opinion is that this is THE way to do it.

As I alluded in my earlier post, this provides a truly closed loop
frequency/doppler correction system.  Setting frequency based on any
calculation is open loop, and subject to variation in satellite
crystals, your LO(s) with temperature, etc.  

Using a doppler corrected calculation to get you in the ballpark and
then let the mic click hardware take over is the way to go, in my humble
opinion.

I've done this successfully with an IC-751 (+transverter), an IC-475,
and a Yaesu FT-736 (two different implementations).  If AO-40 RCV is
already set up to do this, I'd say GO FOR IT!

Hope this helps.

Good luck to all!

Very 73,
Jim
wb4gcs@amsat.org


"Alan P. Biddle" wrote:
> 
> Ed,
> 
> There is no equivalent of UP and DOWN for the FT-847.  It needs a full
> frequency string.  However, the very simple "mic click" interface in the
> AO-40 RCV help file works perfectly.  You can tie into the microphone input.
> I have been doing this for months.
> 
> For long periods of time, you will need to do something like this anyway, as
> the beacon frequency drifts about 300 Hz per degree C of the transmitter.
> That is a stability of roughly .1 PPM per degree, which at that frequency is
> mighty impressive.
> 
> Alan
> WA4SCA
> 
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