UISS, GO-32 & 9600pbs
Hello Nader, I was extreenly interested in your discovery that the UISS program decodes 9600 bps from GO-32 - (and AO-51).
I lost interested in packet radio in 1990 when I moved to Frei Island.
From myQTH, surrounded by mountains, it was nigh on impossible to work
the Pacsats in LEO and of course (for the same reason) the ISS was a non-starter for me, 'm too far north.
However, I just checked - and I see that GO-32 'is' workable from my QTH occasionally. I know how to modify rigs for 9600 bps but my question is ...
Is it possible to make some sort of relatively simple tuning indicator for 9600bps ??.
Tone decoder, centre meter, LED's, old 1 inch tube type RTTY indicator, comparator system ... I can't find any information on the net. 1200 bps is easy but I believe 9600 bps is a different matter - (I am of course showing my digital ignorance here).
Do you have any references to any circuit diagrams Nader ??.
I know you can't actually *hear* 9600bps modulation, hence my request for an 'indicator'.
I believe one way is that the white (background) noise goes quiet when 9600bps is being received.
Confirmation - (or strong denials) - of this would be appreciated from the digital experts among us.
Any advice, tips, references or relavant URL's would be greatly appreciated.
to recap ...
I'm looking for some sort of 'INDICATOR' for 9600bps signals ... (if it's possible).
73 John. la2qaa@amsat.org
Hi John,
{snip}
I know you can't actually *hear* 9600bps modulation, hence my request for an 'indicator'.
I believe one way is that the white (background) noise goes quiet when 9600bps is being received.
Confirmation - (or strong denials) - of this would be appreciated from the digital experts among us.
I'm by no means an expert on 9600 bps modulation, but the few times I've tried it, I found that there is a different noise-like sound when you have it tuned in, but it definitely does not go quiet. There's pretty much no way to describe the difference - it's a bit softer, perhaps, maybe a little higher pitched (less low frequency components). I expect you'll recognize it when you hear it.
Greg KO6TH
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You should also see a difference in received signal strength too.
Swing your VFO either side of the frequency, listen, you will hear a difference, and watch your S meter.
Even without a mast head pre-amp you will see and hear a difference.
An indicator on a suitable TNC would be the receive DCD LED.
73, Dave.
John Hackett wrote:
I'm looking for some sort of 'INDICATOR' for 9600bps signals ... (if it's possible).
Hi John,
I have written a 9600 baud soundcard modem called Willow which includes a 9600 baud signal quality bargraph meter and an eye diagram. The bar graph will give you a visual indication of the received signal (including packets, good and bad, and even if only HDLC flags are being received). The eye diagram should look like two superimposed sine waves that are one hundred eighty degrees out of phase.
Willow also has some helpful audio indicators that it will display such as "No audio" or "Too loud" depending on the audio coming into the soundcard.
And, there's a DCD light which will flicker or light up solid yellow based on the signal quality.
It also demodulates the 9600 baud AX.25 packets. :-)
You can download a copy of Willow at
http://quagliana.com/willow/WillowSabins.zip
It's free. (The Sabins program is the AO-51 telemetry program that comes with Willow. It's also free.)
No installation is necessary, just run Willow.EXE and select "File/Activate Soundcard" to get started.
Let me know if you have any questions, and let me know what you think of Willow.
Douglas KA2UPW/5
participants (4)
-
Dave Aitch -
Douglas Quagliana -
Greg D. -
John Hackett