[amsat-bb] Question about AO-40 telemetry

[Jonathan Naylor <jonathan.naylor@xxxxxxxxx>]

Hello All

Having got around to receiving the telemetry from AO-40 within the last 
few days. I have a question about the telemetry. The E blocks contain 
the same data as the A blocks but are snapshots from a point in time 
labelled with an event number.

Are these event numbers documented anywhere ?

Here is what I have noticed from a quick scan through the data:

Event No.  Date/Time            Comments
0003       2001-01-26/09:24:40  Solar panels are cool.
0004       2001-03-30/09:09:27  Magnetorquing.
0005       2001-04-11/06:09:38  Eclipse ?
0006       2001-04-12/00:46:04  Eclipse ?
0007       2001-04-12/19:40:13  Eclipse ?
0008       2001-05-13/04:12:10  High Temperature Emergency !
0009       2001-07-11/08:08:02  Normal operation.
000A       2001-07-16/13:18:45  Solar panels are cool. Magnetorquing
000B       2001-08-11/23:11:11  Solar panels are cool.
000C       2001-09-15/17:51:08  Magnetorquing. Eclipse ?
000D       2001-10-24/22:02:55  Normal operation.
000E       2001-12-30/16:39:43  Eclipse ?
000F       2002-02-07/10:03:11  Solar panels are cool.
0010       2002-03-29/21:18:00  Magnetorquing. Eclipse ?
0011       2002-03-30/16:24:36  Magnetorquing. Eclipse ?
0012       2002-03-31/11:31:14  Magnetorquing. Eclipse ?

The events marked as "Eclipse ?" have solar panel temperatures that are 
well below freezing. I would particularly like to know what the reason 
for events 0003, 0008, 0009, 000B, 000F, event 0008 seems very strange 
as the temperatures in the E block are below those of the following A 
block(s) which do not have an emergency status. Are the events 
trigerred when specific internal events occur or are they scheduled by 
the command stations ? 

What is also interesting is that when the V receiving is operating, the 
amount of AGC to be seen is usually quite high. This may be because the 
satellite is being commanded, or because of the general crud on 2m, 
which would be particularly bad when the satellite is near perigee. On 
events 000F and 0011 the AGC on the V receiver is above 20.0 (dB ?).

I am using Linux and decoding the beacon using the soundcard, software 
used is modemp3d for the DSP work and ao40tlmview for data 
interpretation and logging. And yes, I am sending the logs into the 
AO-40 telemetry archive. Next job here is to build an RF splitter to 
allow me to have two receivers on the downlink at once, one for 
telemetry and the other for talking to people with.

Jonathan  HB9DRD/G4KLX
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