[amsat-bb] AO-51 CTCSS/PL tone
glasbrenner at mindspring.com
Wed Dec 13 14:07:21 PST 2006
The primary FM repeater modes on AO-51 have historically required a 67 Hz
subaudible tone to access the satellite. This tone was originally designed
to allow the downlink to be switched off when the satellite was not in use.
Because of the difficulties in power management between orbits seeing heavy
use and those with light use, this scheme is not practical with the current
software onboard the satellite. The use of the subaudible tone access has
also been problematic when trying to identify the seemingly growing
interference issues experienced on most 2 meter uplink frequencies, and when
the satellite is over areas of heavy use. Furthermore, despite the near
ubiquity of subaudible tone enabled radios in North America, many areas of
the world have limited or difficult access to this type of equipment, even
in commercial off-the-shelf gear.
After careful evaluation and discussion, I have made the decision to suspend
the subaudible tone access on AO-51 until such time as it becomes necessary
or useful for power management. Please continue to listen to the downlink
before and as you transmit to reduce QRMing other users. This means full
duplex operation is the most courteous and efficient means of operating the
FM satellites. Also, please continue with renewed vigor to help identify and
eliminate both non-amateur interference, and amateurs operating outside of
the established bandplan that interfere with our satellites.
I encourage those with questions or feedback regarding this policy to email
me at ko4ma at amsat.org, and those with special mode requests to continue to
submit them to ao51-modes at amsat.org for consideration. The Operations
Committee will soon begin to put together the schedule for the upcoming
month, and your input is welcome.
73, Drew Glasbrenner KO4MA
AMSAT-NA VP Operations
AMSAT LM 2332
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