Satgen102   Miscellaneous Satellite Data  by GM4IHJ  11th March 91

Microsats  A Microsat User Guide is being produced in USA by KF4AU. It is
hoped to publish in the next 2 months.
WASHING - This question has come in several recent messages. Microsats
operate in a relatively harsh radiation environment. Because the earths
magnetic field is not centred on the earth's geographic centre, but is
centred 600kms nearer Singapore than the geocentre, the radiation
environment is harshest over Brazil and the South Atlantic ( antipodeal to
Singapore )because the Van Allen Radiation Belts come closer to earth in
that region. Radiation causes Single Event Upsets ( SEU), bit flips in the
microsats memory which changes data thereby corrupting files. To avoid
accumulation of SEUs in memory, the memory needs to be read and corrected
regularly (Washed) . Pre launch data suggested SEUs at a rate of 1 per 10
million bits per day. In fact the microsats seem to be registering ten
times more SEUs than this. So files will in future be washed regularly.

Webersat AO18 Some interesting pictures taken in February, but according
to one report the Feb results contradict the results obtained last summer.
Eg wide iris settings last summer seemed to produce under exposure. Narrow
iris settings in February 91 appear to have produced over exposure.

RM-1 digital 1100bps beacon uses PSK synchronous ( but not the HDLC
synchronous mode supported by most TNCs ). Only the AEA DSP - 2232 running
the DSPDATA mode seems capable of decoding it as far as I can see. ( Tell
me if you think I am wrong pse ). This Digital Signal Processor
automatically classifies signals it hears and sets up its modem to suit.
SP GM4IHJ if you want digital telemetry decode for RM-1 and/or RUDAK II
BBS notes.

MIR  The Soviets are considering ways of using one or two specified BBS in
each country, from which U2MIR can upload/download messages. ie you put
your 'hello Musa ' on GB7etc and check there later for a reply. The Mir
Manual is available from 8 Whitehills Saline Fife KY12 9UJ. SASE with
enquiry please. 

Shuttle Discovery did not launch on its ' Over UK ' flight on 9th. It will
be delayed about a month. Meanwhile the Atlantis STS 37 flight is due to
go on 4 April with Amateur radio , but out of range of UK. 73 de John
GM4IHJ @ GB7SAN