The Amateur Radio satellite Uosat-Oscar-11 was launched on 1st March 1984 and nearly 24 years later it is still sending signals back to earth on 145.825 MHz FM.
AMSAT-UK member Clive G3CWV has spent many years analysing the telemetry data from Oscar-11 and he produces a monthly report on the satellite.
In correspondance on the AMSAT-BB email reflector it was noted that the clock on Oscar-11 now appears to be 81 days out.
Clive G3CWV gave this answer:
"I suspect it probably stops during eclipses. It's lost about seven days in 63. That's probably around the total eclipse times. At the present time it's very stable at 81.36403 days slow.
"In the past UO-11 also used to send stored ASCII bulletins as well, but I think that capability of the satellite ended when the spacecraft computer turned off. Anyone know for sure?
"As far as I know, the computer was used to control the diary schedule, which enabled the satellite to capture and transmit many types of data, including a text bulletin. Before the computer switched off, it became difficult to command the satellite to upload the bulletins."
73 Clive G3CWV
Uosat-Oscar 11 1984 Launch Video
(9.64 MB Windows Media file) http://personal.ee.surrey.ac.uk/Personal/L.Wood/UoSAT-2/uosat-2-coming-home
A 64.9 MB MPEG Video of the launch can be downloaded from http://personal.ee.surrey.ac.uk/Personal/L.Wood/UoSAT-2/uosat-2-coming-home.mpeg
UoSAT-OSCAR 11 information
Online Satellite Pass Predictions (Select UO-11)
AMSAT Bulletin Board AMSAT-BB