[amsat-bb] SAFIR-M Status per 26.12.2002

["Oliver Amend" <oliver.amend@xxxxxx>]

The analysis of a recorded WAV file of a pass over Germany
from 24.12.2002, 05:38 - 05:40 UTC shows unexpected effects:

a) The TX clock rate of the SAFIR-M 9k6 modem seems to have
   9844 Baud instead of expected 9600 Baud. A receive of
   frames may be still possible with high RX fieldstrength
   so that the DPLL of the ground equipment can lock within
   its tolerance range.
b) Additional it seems that the data line for bit 0 to the
   external memory of the PIC is stucked to "0", so that the
   parts of the transmitted MH frames could be damaged. CRC,
   NRZI, stuffing and scrambling are done correctly from the
   faulty data source.

These effects will be analysed within the next passes.

For further examination, Martin DG8UAU has written a small
software "SAFIR-M Decoder" (28kB) to allow a decoding of the
received DATA0 frames. It is available on the SAFIR-M Homepage
http://amend.gmxhome.de in the section Aktuelles.

The news information are also available there from now on as
english translation...

73 de Oliver, DG6BCE

SAFIR-M Homepage: http://amend.gmxhome.de
Mail pse to :     DG6BCE@aatis.de
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