[amsat-bb] Re: GTO-Track

Paul Williamson kb5mu at amsat.org
Thu Oct 19 19:41:56 PDT 2006

At 7:53 PM -0400 10/19/06, Brad, K1GTo wrote:
>You were a little hasty to shoot down the basis of the idea. If we think
>about it for a moment, how many people do you know with dual-band radios in
>their vehicle? Then think about how many people can full duplex between
>those bands. There are a few but most can't. My 706 can't, and that is what
>is driving me to write this application.

My objection was to the proposed implementation (using a remote 
Predict server), not to the function.

However, now that I understand your goal I will say that I am not 
really in favor of it. If you run a half-duplex transceiver on an 
analog transponder, you will have to rely on guesses and reports from 
other operators to set your uplink power level. That's less than 
ideal. There's not a lot of range between too weak to hear and too 
loud, and that range is not entirely predictable. Perhaps when we 
have SDX-based transponders with effective alligator control, it will 
be OK to set your power open-loop.

Nonetheless, it's an interesting project and I wish you success.

>As a side note, phase-2 of the project will let the user plug in key
>attributes (probably about 5 numbers) of an upcoming orbit, so they can work
>the sat without network connectivity. Even these calculations can be
>simplified enough to allow for a small phone to continuously tune the TX and
>RX freqs on the radio, or tune the TX after the user adjusts the RX.

I will be interested to see what you come up with along those lines. 
I have speculated about something similar, but never stopped to think 
it all the way through.

73  -Paul
kb5mu at amsat.org

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