[amsat-bb] Re: Satellite's
Mike Seguin N1JEZ
n1jez at burlingtontelecom.net
Wed Aug 29 09:29:14 PDT 2012
The "uplink" connection in the panadapter seems to be the missing piece
right now, but truthfully, I have not looked lately to see what's available.
I can tell you that HDSDR and Omni Rig work well with the FT-817 and the
FUNcube. In HDSDR, the tuning controls the FT-817 (and tuning the FT-817
manually updates HDSDR) and behind the scenes, HDSDR locks the FUNcube to
68.33 (or whatever you set it to use - I use 68.32 to get away from the DC
offset spike). But, no doppler control.
I guess if I were going to do it, I'd tap the common IF of my FT-847. Then
use SatPC as usual to control the 847 and HDSDR to just display the FUNcube.
I wouldn't have full integration, but I'd be able to see most of the
passband and could simply tune the 847 to receive the downlink. SatPC would
compensate for uplink Doppler.
I could probably do the same with an FT-817 or two of them....
Having the ability to see other signals in a +/- 40 kHz window (for those
weak signals off frequency) was the big plus for us working microwave and I
could see it being a big help in satellite work as well.
"A closed mouth gathers no feet"
----- Original Message -----
From: "Thomas Doyle" <tomdoyle1948 at gmail.com>
Subject: Re: [amsat-bb] Re: Satellite's
> 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
>> W1FKF and I have done on tapping the common IF in the FT-817 and using
>> FunCube as a Panadapter. Our primary application is weak signal
>> I would think it would work well for satellite. That way your software
>> 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.
>> 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
> Sent from my computer.
> tom ...
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