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


AMSAT et al,

I posted some WAV files of what I am hearing at Apogee on the 40 footer.
Since the spin modulation is known, maybe you guys with DSP can recover
the data.  My DSP-12 does not.  It only flickers.

There are five 1 minute recordings which span about 6 minutes.  The
computed doppler moved by only about 25 Hz during these recordings, but I
noticed much more than that change in pitch.  My estimate would be about
100Hz or more.  Moving upward.  Probably my converter drift.

Date is 01-05-2001
Ground Station is at 39.0 N -76.5W
Dish is 12 meter with 60 degree LNA (at 2200 MHz) with 30 dB gain
Converter is just an LO and mixer (1980 MHz)
Receiver is an AOR-5000 tuned to 421.3 +/-, USB with 3 KHz filter
Signal shows about 1/2 S unit above the noise which is S7
Recorded at 8khz sample rate, 8 bits

FILE              start time  Doppler  Range  MA   AZ   EL
----------------  ----------  -------  -----  ---  ---  ---
a40-01051553.wav  15:53:30    497      54k    175  173   50
a40-01051555.wav  15:55:00
a40-01051556.wav  15:56:30
a40-01051557.wav  15:57:49
a40-01051559.wav  15:59:30 
                  16:02:?     522      53k    177  179   50.6

The Doppler, Range, AZ,EL were taken at the start and end of the session
and only recorded to integer values.  Next time, I will be more precise.

Files are posted on ftp://tapr.org/aprssig/dosstuff/APRSdos/a40-0105.zip

If there is recoverable data here we can do this as needed, though it does
take manual intervention during working hours... etc..

de WB4APR@amsat.org, Bob
US Naval Academy Satellite Lab

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org