[amsat-bb] Re: Satellite's

Thomas Doyle tomdoyle1948 at gmail.com
Wed Aug 29 08:47:11 PDT 2012

Hi Mike,

I have two radios that have a built in panadapter and have used the
dongle as a stand alone panadapter. The problem is all the panadapters
I have used or read about, other than SDR based gear like the Flex
radios, do not have a connection between the panadapter and the
frequency control of the radio. With an SDR receiver you click on the
waterfall or spectrum display and the radio is tuned to that
frequency. That is what I am trying to do and that bit you get for
free with an SDR receiver the hard the part I am trying to solve is
controlling the transmit frequency (including doppler correction and
offset) when using linear sats. The only way I have been able to do
this so far is to use SDR-Radio with its built in doppler correction
for the receiver and my IC-7000 as a transmitter under the doppler
corrected frequency control of SatPC32. This works but changing the
frequency on the SDR does not adjust the transmit freq. I am hoping
someone has actually done this as I have never been a big fan of
reinventing the wheel.

The FT-817 is a very cool rig and I will be very interested to see how
you control the FT-817 frequency from the panadapter - that is the
tricky bit since the panadapter does not have to even know what
frequency you are receiving. It should be possible to poll the
panadapter for the offset of the frequency you have clicked on and add
that to the FT-817 frequency and feed it back into the FT-817.   I am
sure you guys have come up with something. Thanks for writing the
article. I look forward to reading it.

73 W9KE Tom Doyle

On Wed, Aug 29, 2012 at 9:18 AM, Mike Seguin N1JEZ
<n1jez at burlingtontelecom.net> wrote:
> Hi Tom,
> There will be an article coming up in the AMSAT Journal on work that W1GHZ,
> W1FKF and I have done on tapping the common IF in the FT-817 and using the
> FunCube as a Panadapter. Our primary application is weak signal microwave.
> I would think it would work well for satellite. That way your software would
> be controlling an FT-817. The common IF is centered on 68.33 MHz in the
> FT-817, so you see +/- 40 kHz around that. You would be able to take
> advantage of all the front end filtering in the FT-817.
> 73,
> Mike, N1JEZ
> AMSAT 29649
> "A closed mouth gathers no feet"
> ----- Original Message ----- From: "Thomas Doyle" <tomdoyle1948 at gmail.com>
> Subject: [amsat-bb] Re: Satellite's
>> I am close to a SatPC32 <-> dongle system but there is probably
>> someone with a much better 'simple' or even a 'very simple' solution.
>> I would be very interested in hearing from anyone who has actually
>> achieved fully synchronized doppler corrected transmit control with a
>> dongle for the receiver. A reply offline would be best to prevent
>> flames.


Sent from my computer.

tom ...

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