Patience is required when monitoring satellite transmissions as the monitoring of sessions may fail, in particular fax sessions. The reasons for the failure may be:
Ø The W61PC monitoring system cannot synchronize to the traffic channel because the traffic channel is not in a spot beam seen by the antenna, or it is too weak. Check the FFT display.
Ø The W61PC monitoring system cannot synchronize, or it may synchronize, but after some time it loses synch, because the traffic channel is in a spot beam which is disturbed by a neighbor channel. This neighbor channel can be inactive at the beginning of the session, but is activated after a while. Check the FFT display.
Ø The session is terminated after less than 100 seconds and no fax is received. Many fax sessions never start transmitting fax data, because the handshaking process at the beginning of the session fails. The handshake may take as long as 120 seconds.
Ø The fax transmission is successful, but the fax viewer does not display anything or displays only a partial fax. This could be due to bit errors preventing the fax decoding process or because the fax devices during the handshake agreed on a coding version not yet implemented in the WAVECOM fax viewer.
Ø The fax transmission is successful, but output is not the default .TIF file, but a .JBG file, because fax encoding is according to recommendation T.82/85. Call WAVECOM for support on this issue.