[amsat-bb] AO-16 update 8 SEPT 2008

Mark L. Hammond n8mh at embarqmail.com
Mon Sep 8 12:52:36 PDT 2008

Hello All, 

As Drew KO4MA communicated recently, it appears that the recent reduction in eclipse/increase in illumination is having a favorable effect on AO-16 and its ability to sustain longer periods of voice operations.   Our best theory is that a temperature sensitive hardware timer is responsible for the shutdowns.  The current increased illumination periods are causing an increase in spacecraft temperatures (as observed from MBL telemetry).  These increased temperatures appear to be favorable for the hardware timer and therefore for AO-16 operations.   We are now seeing several hours of operation between transmitter shutdowns.   We anticipate that things will improve further in the immediate days/weeks ahead. 

Current orbit predictions suggest that illumination will improve until mid-October , after which time the eclipses return---and with the eclipses come lower temperatures, and the hardware timer issue returns, shutting down the transmitters every few minutes or so.   Sadly, AO-16's orbit is such that after this Sept/Oct/Nov period  it will be many, many years before the orbit is again favorable. 

We encourage you to record your observations of AO-16 on this very useful and intuitive web site: 

http :// oscar . dcarr .org/ 

The Command Team uses this site regularly as a means of monitoring the status of AO-16 .   It gives us a good idea on the length of time between shutdowns of the transmitter.  We also use this site to "announce" that we've turned AO-16 back ON. 

Friendly advice--if you want to log some AO-16 voice contacts, you had better make them SOON! 

Mode FM Voice Repeater ( Downlink is DSB . Operation is Intermittent): Semi-Operational 
Uplink : 	145.9200 MHz FM 
Downlink 	437.0260 MHz SSB 

On behalf of the Command Team, 

Mark L. Hammond [ N8MH ] 

More information about the AMSAT-BB mailing list