[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: 38k4 radios and modems ?



	Time ago I used a PCR-1000 hooked to a DSP56002EVM to receive UO-36's
38K4 downlink. Efficiency was not as good as with 9K6 downlinks but it
worked. The modem implementation for the EVM was very new (sort of
experimental) maybe a 38K4 TNC would work better now, or the modem
implementation could have been enhanced. Doppler correction was with
wispdde.

	73,
Nando - CX6DD

On Fri, 25 Feb 2005 11:53:59 +0000
John Melton <John.Melton@Sun.COM> wrote:

> 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
> ----
> 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



AMSAT Top AMSAT Home