AO-40 Update – 9 March 2004
Gentlemen,Today during the period 0310 to 0320 UTC (orbit 1541) I observed the following.
Prior to issuing the command sequence we tune around the beacon frequency, taking note of the noise spectrum . No variance in amplitude detected, just clean white noise. At 0310, commenced sending a 12 block sequence, 3 * (Reset,Tx-Off,Reset,Tx-On).
At the completion of the sequence, again tuned around the beacon frequency, and noted a noise peak of 4 to 5 db, in the vicinity of expected beacon frequency.
The width of this peak was about 5 kHz. Listened to it for about 15 seconds and then sent a Reset, Tx-Off command and the noise peak disappeared, approximately 2 seconds after the Tx-Off block was completed.
Completed my session with a number of Aux-Batt commands, but did not attempt the Tx again.
Range was nominally 12000/15000 kilometres during command period. Was using my last calibrated uplink frequency.
This tends to suggest that the IHU and L Band Rx are ok.
Bus voltage insufficient to open that damn relay.
Considering SA=-72, the remaining cells are holding up well. Hope this makes your day, like it has mine.
Colin Hurst, VK5HI for the AO-40 Command Team
Klla: amsat