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Re: An Open Letter To AMSAT



on 12/18/00 7:47 PM, Laura Jolley at jolleybuckaroo@hotmail.com wrote:

> For this to work (and I am speculating here although
> it could be cleared up pretty quick) this would require as a minimal thing
> that at least one command reciever be working and two the "master reset"
> circuitry be intact and three that their be something functional to reset.

The master reset circuitry is able to be activated independent of the IHU.
Additionally, the L band RX is on ALL the time.  And either the 2m or 70cm
RX is on.  So there is always at least 2 receivers functional at all times.

There is always a possibility that the RF circuitry failed, but having been
an RF designer, I know a little about that.  Most of the time you have
either an "infant mortality" or failure after a long, long period of time.
Very rarely does something work for a couple of weeks and then stop.  It is
not impossible, but IMHO, unlikely.

> 
> So to summarize based just on what the folks have let us know it strikes me
> that 1) there is a window that closes at whatever time plus interval that
> the on board reset will fire then 2) there is a last ditch chance to send
> this master reset.  I would wonder what has to be working on the satellite
> for that to work...?

There is no window that closes as you speak of.  The COMMAND-ASSIST mode
goes into affect after a certain amount of time of no commands being
received.  From what I have read, we have never reached the point of the
COMMAND-ASSIST routine activating.  When it happens, the bird will try to
transmit telemetry or a carrier or whatever on various combinations of bands
and antennas.  If this functionality works, we will all know it.  Again,
this bird is loud.  If it begins transmitting, we won't need EME arrays to
hear it.

73,

Jon
NA9D

-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

My President is George W. Bush -> The legal winner in Florida

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