[amsat-bb] Ideas regarding a predict client for full doppler tuning

[Bruce Robertson <broberts@xxxxxx>]

Quoting "Greg D." <ko6th_greg@hotmail.com>:

> I haven't seen the new UI in 2.2.2; what does it look like?

I don't want to speak for the developers, but my post wasn't referring to
UI changes in 2.2.2 as much as announced support for linear transponders
from the web page, reading: "In Single Satellite Tracking Mode, a wealth of
real-time satellite data is provided by PREDICT. If the satellite contains
an active communications downlink, uplink, or two-way communications
transponder, then Doppler-corrected uplink and downlink frequencies, path
loss, propagation delay, and echo are displayed. It is also possible to
tune across the transponder's passband using certain keystrokes to locate a
specific uplink or downlink frequency within the satellite's transponder.
This makes it possible to determine the appropriate uplink frequency to
match a desired downlink frequency (or vice-versa). PREDICT supports a
number of transponders per satellite, including linear (both inverting and
non-inverting), digital (Pacsat), and bent-pipe (FM)." I'm interested in
getting these capabilities hooked up to a tranceiver, or pair of
tranceivers to implement a very lightweight full doppler tuning.



> I'm running a modified version of Diane Bruce's 2.2.1.  (The mods were
> to 
> output the Az/El string my controller needs (Yaesu format), and to
> display 
> the time as local instead of UTC.)  I have also written a small UDP
> client 
> to control my Yaesu FT-736R radio for doppler, but it's really only good
> for 
> the FM sats.  The program is a simple command-line driven thing, with
> the 
> command line specifying the satellite name and un-shifted uplink and 
> downlink frequencies.  To be useful on SSB or CW, you need more of a
> knob 
> that you can scan across the band to find the spot you want to operate,
> THEN 
> hit a button to lock in the up and downlink.  Since you can't read from
> the 
> 736R's CAT interface, the "knob" would need to be in software.  A nice 
> little GUI program might be the thing, but my GUI programming skills are
> 
> lacking.

I've written something similar in perl, and then rewrote it in python
considering that the hamlib folks provide python stubs. The idea was to
track a single frequency on a single bird using predict as a server.

Your description of the 736R's limitations raises the central problem of a
project like this: the multiplicity of interfaces and use modes. It's
amazing that something like Ham Radio Deluxe works so well.
 
> Anybody want to start a project for this?  I know what I want - even
> bought 
> a book on QT programming to write it - but haven't gotten the time to do
> it 
> yet.

I would recommend the following parameters for any such project:

1. As OS/platform agnostic as possible. Since predict can work all over the
place, so should a client. I would think this might mean using either java,
or a scripting language as well as a cross-platform gui package. With
sufficient abstraction, command-line and gui version could both be offered.

2. Built around hamlib

3. Operate with multiple rigs using the logic employed in WispDDE. WispDDE
brilliantly binds rigs according to band, mode, bird; it doesn't specify
one rig as 'transmitter' and another as 'receiver'. Given that we work mode
J and B, and occasionally V/S, soon with any luck U/S, I can't see how the
'transmitter/receiver' logic serves anyone. The multi-rig user needs to
reconfigure his software every time he switches from VO-52 to SO-50.

On the other hand, if an unlimited number of rigs could be bound according
to band/mode/bird then one could just buy another FT-817 and a couple of
transverter to add S-band and L-band operation to a station. As far as I
know, WispDDE only allows two rigs to be controlled, and I've reported a
bug whereby the most recent 
version doesn't properly track the frequency reported by the server
application.

4. Aim ultimately to be able to serve as a client for other, DDE-based
servers such as Orbitron, PCSat. This is just a matter of abstracting out
the code that connects to the server.

Anyway, as I've been thinking about these things recently, I thought I'd
put them in print for discussion. I'd also be excited about working on such
a project if my skills permitted it.


73, Bruce
VE9QRP

> ----Original Message Follows----
> From: Bruce Robertson <broberts@mta.ca>
> Reply-To: brobertson@mta.ca
> To: John Heaton <john@manchester.ac.uk>
> CC: AMSAT-BB <amsat-bb@amsat.org>
> Subject: Re: [amsat-bb] Predict 2.2 and LVB Tracker issue
> Date: Sat, 29 Apr 2006 08:57:24 -0300
> 
> Quoting John Heaton <john@manchester.ac.uk>:
> 
>  > -----BEGIN PGP SIGNED MESSAGE-----
>  > Hash: SHA1
>  >
>  > On 29 Apr 2006, at 08:33, Howard Long wrote:
>  > > I'm afraid that I currently don't have a Linux machine to try
>  > > Predict on.
>  >
>  > Have you tried running Predict under Cygwin on Windows XP.
>  >
>  > The DOS version of Predict is a bit lacking in features compared to
>  > the Unix version, but if you install Cygwin under XP then the Unix
>  > version will compile on that.   You could even run my version of
>  > Predict which has even more features..
>  >
>  > John, G1YYH
> 
> If you like predict, you owe it to yourself to look at John's patched
> copies of 2.2.1: their UI improvements are quite fine.
> 
> Apropos the recent discussion about track boxes based around a small
> pc,
> I'd love to build a tiny dedicated machine around linux/predict. Does
> anyone have any successful experience using the linear transponder
> features
> in 2.2.2 to implement full doppler tuning? Ideally, the client program
> would be able to use the UDP connection to request uplink frequencies
> corresponding to a given downlink. Then it would be pretty easy to use
> the
> hamlib libraries to control various radio hardware.
> 
> 73, Bruce
> VE9QRP
> ----
----
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