[amsat-bb] AO-7, request for information

[Larry Kayser <kayser@xxxxxxxxxxxx>]

Greetings:

I have now recovered some of the early notes I kept on AO-7 after it was 
launched.  It would be very helpful if those of you who are active on AO-7 
now would look carefully for the following conditions.

When AO-7 is in MODE A, look for MODE B to be on at the same time.
When AO-7 is in MODE B, look for the 435.1 beacon to be on at the same time.

If these undesirable conditions were to exist, and with truly random logic 
states they could exist, they might indicate why some of the worst FMing 
and other aberrations in the signals might be explained to some degree.

IF things inside the control logic are really waking up in a random state, 
then one should also hear whatever is going on inside the CODESTORE box 
coming out the telemetry ports on occasion.  This would mostly be 
meaningless garbage BUT it should be repetitive at least two or three times 
over a regular overhead pass of AO-7.

There should also be some occasional 45.4545 baud data coming out of the 
telemetry ports.

Last but certainly not least, observations, on multiple frequencies at 
once, at the TURN ON, ie when AO-7 enters sunlight, made carefully would be 
of great interest.  The 435.1 beacon has special logic internally that is 
supposed to prevent the beacon from coming ON when the power supply and the 
ON/OFF beacon control signal line wake up at the same time.  This was a 
major design effort and was tested here for many months and many hundreds 
of thousands of cycles.  The timing capacitor to effect this delay was a 
very high quality unit and was NOT of the electrolytic type - it should not 
have failed.  It would be immense interest if we could find out if the TURN 
ON where the MODE A transponder beacon came ON and the 435.1 beacon came ON 
occurred at the same time or with an offset in time.  The offset in time 
could be as little as 300 milliseconds but should be well over 1 second.

The deaths of OSCAR VI and VII were very different.  OSCAR VI died because 
of cell degradation but this was mitigated by most of the control logic 
having fluxed up into the never never region above a logic "0" and below a 
logic "1".  Control simply became impossible.  Late in life we regularly 
shut AO-6 OFF for periods to let the logic drain down.

I have been reviewing my notes of that time and I never remember nor do my 
notes show any apparent flux up logic being an issue with AO-7!  I am sure 
there was no difference by intent between the two satellites yet there is a 
serious difference between the two satellites.  If anyone has any thoughts 
on this I would appreciate some thoughtful discussion on the subject.

There is a continuing need for very careful and ongoing analysis and 
observation of the way that AO-7 is operating.  It is only with new 
knowledge of what exists inside AO-7 that will tell those interested what 
can be done and what might be done with the existing state of the bird.  I 
urge those with resources to make observations and very detailed notes on 
what is observed.  The sequence of events, including time references can be 
very valuable.

Last, but not least, if the control logic is waking up truly randomly then 
2.3 GHz beacon should be coming up as well from time to time.  Those of you 
with AO-40 resources should be able to hear this signal.  Reports of this 
event would be of great interest to many.

For the moment I am watching this reflector for any relevant observations 
of AO-7.

Larry
VA3LK

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