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CD-ROM of satellite recordings (Was: 9600 baud test with .wav file?)



Ron Long in a message dated 99-09-23 09:28:52 EDT writes:

> 1. Is it possible to play a .wav file of 9600 bd satellite data for testing
>  a new modem/tnc setup?

This is possible provided that the sampling rate is high
enough.   (The 44k sampling rate would be best.)

>  2. If so who has a file to share?

I can probably record something from my 9600 TNC/modem.

>  3. Are there limitations concerning the speed of the computer, sound card
>  type etc.

The computer must be fast enough to read the samples
of the .WAV files and send them to the sound card at
the 44k sampling rate.   Any computer you picked up in 
the last few years will do this.  The sound card must 
support the sampling rate you want to play at.  Almost
every sound card will play at the Windows "standard"
rates of 11025, 22050, and 44100 samples per second.
However, some soundcards do not accurately playback
at *exactly* this speed (that is, 22050 might be played
back at 22222).  This is okay for music or voice, but
not for data.  Note: DSP programs that generate or
receive digital modes can compensate for this inaccuracy
on the PC cpu side if they know the exact sampling 
frequency.


>  4. If the above is possible could AMSAT prepare a CDROM for this purpose
>  and collect donations for it? There could be files of various sizes - 1min,
>  5 minute etc. Could P3D telemetry be included?
>  
I'm willing to do this.  I've actually wanted to put up a 
"Sounds of Satellites" web page for awhile but a CD-ROM is
better from a modem-testing/development point of view.

I have a CD-ROM burner and some experience at producing 
CD-ROMs for AMSAT.  (I scanned the QSL cards for the 
"Fly Your QSL on P3D" campaign and burned them onto the 
CD-ROM that is now attached to P3D).  While I already have 
several recordings, I could always use more. (hint!) I was really 
interested in getting a recording of P3D's telemetry but I never 
actually got a recording.  If anyone has .WAV file
recordings (or *ANY* other format) of amateur satellite data 
transmissions I would love to have a copy -- email me and
let me know what you have !

  I also have some DSP programs that will run on a Pentium
that will generate some common formats (1200 baud AX.25 
AFSK, PSK, etc) and play them out of a soundcard.

   I'll get in touch with Martha when she returns to the office.

>  thanks ron w8gus.

Douglas KA2UPW
dquagliana@aol.com
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