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RE: AO40 12m WAV files


This is very good work. The signal is quite strong but I can't decode it
with AO40rcv (Alpha V0.1) or the IZ8BLY decoder (V0.3). Phil, are you
able to use these files to design an optimized decoder?  I was hoping
for some feedback so Bob (WB4APR) would know his efforts are

In the AO40-2001-01-18-B.wav file I noticed a pattern of nulls in the
carrier that occur at intervals of approximately 1.36, 0.95, 1.05, 1.36,
0.95, 1.05, ... seconds. Thus a repeatable set occurs at a rate of once
every 3.36 seconds suggesting a satellite rotation rate of 17.86 RPM. I
assume the nulls within this repetition are caused by obstructions like
the 400N nozzle because we are looking at the antenna from the side as
it rotates. I found similar patterns in the other audio files.  I would
like another set of files soon so we can look for changes in the
satellite spin rate.

This agrees with Bob McGwier's observations of the data you recorded on
the 14th (see Bob's e-mail Mon 1/15/2001 11:10 AM "Re: AO40 Telemetry


-----Original Message-----
From: Bob Bruninga [mailto:bruninga@usna.edu]
Sent: Thursday, January 18, 2001 9:59 AM
To: Richard M. Hambly
Cc: MCGWIER ROBERT; karn@ka9q.net; wb4apr@amsat.org;
ron.parise@gsfc.nasa.gov; amsat-bb@amsat.org
Subject: Re: AO40 12m WAV files

Some new 5 minute WAV files for AO40 MA 24 to 32 taken with the 12 meter
dish in my WEB directory:


18 Jan 14:06:30 24.7 27,800  AO40-2001-01-18-A.wav
18 Jan 14:21:30 28.1 30,400  AO40-2001-01-18-B.wav
       14:28:15 29.6 31,600                  C
       14:37:10 31.6 33,000                  D

de WB4APR@amsat.org, Bob

See my APRS LIVE pages    http://web.usna.navy.mil/~bruninga/aprs.html
See APRS SATELLITES       http://web.usna.navy.mil/~bruninga/astars.html
See MIM/Mic-E/Mic-Lite    http://www.toad.net/~wclement/mim2.htm

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