Re: Re: [amsat-bb] 38k4 radios and modems ?

["Mark L. Hammond" <mlhammond@xxxxxxxxxxx>]

Hello John and Graham,

Thank you both for again confirming the abilities of the PCR-1000 for 38k4 packet.  I wish we had more air time to test!

CX6DD Nando's very fine program WispDDE allows serial/computer control of the PCR-1000, and it works quite well.  You can set the audio level, which mode, what filter settings, etc. and it will do the frequency correction just fine when running with Wisp.  I have used WispDDE and Wisp to grab some WXSAT images a while back, so it can be automated to work well.

Maybe we can coax Erich DK1TB to add the PCR-1000 to his very fine SatPC32/DDESat32 programs, too :)  I know I'd be happy to test it.

What I find difficult is getting it all automated to work effectively with an S-band downconverter; I need to get a better handle on the stability of the downconverter frequency, as I suspect this may be the culprit.

Now that I have two confirmed/working TNCs (okay, one is a DSP ;) for 38k4, I think I will try to get my TAPR DSP56002 EVM unit outputting 38k4 data (presumeable it can, by just a quick edit in the code so it xmits 38k4 instead of 9k6).  So, essentially EVM 38k4 OUT --> Paccomm 38k4 IN is the test.  If I can get that working, then I can begin an attempt to record (and playback) some 38k4 packet audio files for Doug (and others that might be interested...), as well as experiment a bit with the PCR-1000 in my shack.

Looks like a fun project for this weekend!!

73,

Mark N8MH

> 
> From: John Melton <John.Melton@Sun.COM>
> Date: 2005/02/25 Fri AM 06:53:59 EST
> To: Graham Shirville <g.shirville@btinternet.com>
> CC: John.Melton@Sun.COM,  Tim Tuck <tim.tuck@penrith.net>, 
>         Amsat-bb
>   <amsat-bb@amsat.org>
> Subject: Re: [amsat-bb] 38k4 radios and modems ?
> 
> I can also confirm that the PCR1000 works well for 38k4 data.  You do
> need to adjust the tuning for doppler for optimal results.  The PCR1000
> should be configured for Narrow FM at 50 KHz and you should use the
> standard 9600 packet socket for connection to the TNC.  The Wide FM uses
> a different circuit in the receiver and does not have any takeoff for
> the digital signal.
> 
> Although not published by Icom,  the commands to control the PCR1000
> have been well distributed on the web.  I believe that there is some
> code to work with WiSP available.  I wrote my own in Java as I do not
> run any Microsoft systems!
> 
> Regards,
> 
> -- John  g0orx/n6lyt
> 
> On Fri, 2005-02-25 at 10:52, Graham Shirville wrote:
> >  Hi All,
> > 
> > Yes I can confirm the PCR1000 with a DB6NT downconverter is working very
> > well listening to 38k4 data coming from the S band transmitter on SSETI
> > Express - at least across the cleanroom where testing is presently
> > underway!!! - Watching the packets fly across the screen makes 9k6 seem as
> > slow as 1k2 seemed when we had 9k6 for the first time......
> > 
> > Two caveats on using the PCR1000  tho - the quoted "wideband" bandwidth is
> > listed as 50kHz which is marginal for 38k4 data - although I dont know the
> > actual bandpass shape and suspect the edges are very "soft" - and I am not
> > sure how you would control the tuning for doppler but as it is a computer
> > controlled radio I assume it should be possible.
> > 
> > Our "guru" Howard G6LVB is presently undertaking further research into this
> > area so your results with AO51 will be very helpful in assisting us to make
> > sure we have everything as right as possible for the SSETI Express
> > groundstations - both the amateur and university ones.
> > 
> > By the way the SSETI Express launch date has slipped a little - now not
> > expected until late July......
> > 
> > If you wish to see a photo of the dual band U/S "groundstation" as it exists
> > at the moment click here!
> > 
> >  http://sseti.gte.tuwien.ac.at/WSW4/express5.php?pag=3  and then on pic 148
> > 
> > 
> > best 73
> > 
> > Graham G3VZV
> > ----
> > 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
> -- 
> John Melton <john.melton@sun.com>
> Sun Microsystems, IT CTO
> ----
> 

 
Mark L. Hammond    [N8MH]
----
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