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Re: Doppler programming question - more



Jim:

Indeed it is. I use three one-wire A/D converters and some
opto-isolated solid-state relays to operate the rotators.
The Tini serial port runs at 56700 to the radio (FT847).

Tini software is in Java.

Art
N3OY


Jim Sanford wrote:
> 
> Art:
> I'm curious what hardware you used; by chance was it a TINI??
> 
> 73,
> jim
> wb4gcs@amsat.org
> 
> Art Goldman wrote:
> > iPhil:
> >
> > I'm in the process of rewriting the user interface for my
> > custom rotator/radio control box. The controller runs Java
> > and sits on the Ethernet. The user interface is being done
> > in Java so it will "run anywhere", and talks over Ethernet
> > both to NOVA and the control box. Of course, the control of
> > the radio is via a serial interface from the controller.
> >
> > I get tracking info from NOVA using a TCP connection. I
> > worked with Michael to get that feature added. It's now in
> > the current version of NOVA. Later on, I plan on adding
> > predict as a tracking server.
> >
> > I already have one interface running in Visual Basic, and as
> > you stated, it corrects both the transmitter and receiver
> > for doppler. Otherwise, as doppler changes, the transmit
> > frequency as seen in the downlink passband would drift
> > up/down. The Java version will do the same.
> >
> > Art
> > N3OY
> >
> > P.S. FYI for those who write their own software. As of
> > Visual Basic.net, Microsoft has dropped support for DDE.
> > That's why I convinced Mike Owen to support a TCP connection
> > In NOVA to obtain the same tracking info put out over DDE.
> >
> > He's got it set up to accept a TCP connection on a port you
> > specify, either from any machine, or only from a specific
> > host. (Security, you know.) Then, every time you send
> > "SUMMARY" over that connection, NOVA responds with the
> > tracking data string.
> >
> >
> > Phil wrote:
> >
> >>Thank you all for the replies. I have a lot to read and will digest them
> >>offline.
> >>
> >>A couple of points so far:
> >>
> >>1. I don't need to calculate the Doppler shifts; I'm getting those from
> >>Predict running in server mode. So I'm confident that at least that part is
> >>correct.
> >>
> >>2. I am trying to correct both the up and downlink frequencies at the same
> >>time. I'm told that I shouldn't do this. Isn't that the aim of "the one true
> >>Doppler rule"?
> >>
> >>3. If I correct just the downlink then the beacon stays fairly well in tune
> >>for say ten minutes or so on FO-29. However, my uplink drifts and that's why
> >>I started on uplink correction.
> >>
> >>I've tried to get enlightenment from other tracking programs, including Itrack
> >>for Windows, but it isn't easy trying to understand undocumented code.
> >>
> >>I'll think about this some more, during the night when I should be asleep no
> >>doubt.
> >>
> >>By the way, I'm pleased to have added two more countries to my growing list of
> >>contacts made on AO-40, none from the US yet.
> >>
> >>--
> >>Regards,
> >>Phil.
> >>
> >>----
> >>Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> >>Not an AMSAT member? Join now to support the amateur satellite program!
> >>To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
> > ----
> > Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> > Not an AMSAT member? Join now to support the amateur satellite program!
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
----
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