[amsat-bb] SO-50 timer

Kevin M n4ufo at yahoo.com
Tue Jul 14 04:44:36 UTC 2015

A question was recently asked in a popular ham forum about resetting the 10 minute timer on SO-50 and the results showed some ignorance concerning exactly how the timer operates. It is not like a terrestrial FM repeater... the timer is not affected by the amount of 'on air' activity. It WILL shut the repeater off ten minutes after it was last reset. It does not matter where over the planet it is at the time. It will shut off in the middle of a busy pass, even in the middle of someone's transmission. The only thing that resets it, is transmitting the proper 74.4 Hz reset tone. And keep in mind, it will not retransmit your signal while sending the 74.4 Hz tone... it will transmit again the next time it receives a signal with the 67 Hz tone.
This is important information, even for beginning operators to be aware of, because when the timer needs to be reset, it needs to receive a clear signal. If stations of equal strength keep trying to transmit at the same time as a station trying to reset the timer, signals will collide and the satellite will not receive the reset tone. I suppose it's a crap shoot as to who should or will reset the timer, but if in doubt, err on the side of caution and stop transmitting. Especially if you are have a minimally powered station such as an HT. Unless of course, it's a late night pass and you are the only one on. =^)
I just wanted to get this information out there so new satellite operators are educated properly. Proper understanding is key to effectively using a shared resource such as a satellite repeater/transponder. And that goes for new and experienced operators alike... =^)

Kevin N4UFO

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