AMSAT-NA’s new “Echo” satellite (AO-51) will be turned on for general use in FM repeat mode Friday, July 30, at about 0215z, for a trial period of about three weeks. During that time, command stations on Earth will monitor AO-51’s power budget and adjust the UHF Transmitter B (TX B) power as needed for good battery management. They’ll also be watching the AMSAT Bulletin Board e-mail reflector, amsat-bb@amsat.org, for reports of how Echo is working.
“We are most interested in hearing about how well Echo hears you and how well you hear it,” said the Echo Command Team–Jim White, WD0E, and Mike Kingery, KE4AZN–in an AMSAT bulletin. The digital transponder and the store-and-forward BBS, are not yet open for general use.
Initially, the AO-51 downlink transmitter will be running at about 1 W. At that power level, AMSAT says, Earth stations will need a small directional antenna to hear it. If onboard power permits, ground controllers will slowly increase the transmitter’s output during the trial period.
The Echo FM voice uplink frequency is 145.920 MHz, and the downlink is 435.300 MHz. The downlink transmitter will come on when it hears an uplink signal with a 67 Hz CTCSS (PL) tone for about 1 second, and it will stay on for 10 seconds after that signal goes away. “This operation is just like a terrestrial FM repeater with a 1 second ‘kerchunk’ filter and a 10 second hang time,” AMSAT noted. Transmitter A (TX A), now sending telemetry, generally will continue to operate on 435.150 MHz.
AMSAT points out that Echo, which launched June 29, is still “wobbling a great deal,” so the downlink polarization sense will vary.
The Echo Command Team says it expects Echo will be heavily used during the first few days of the trial period. “Many stations will be trying to make a contact through Echo,” they said. “It is good amateur practice and common courtesy to let everyone have a chance. Echo will hear you as well as or better than any previous amateur FM repeater satellite.”
There’s more information on the AMSAT Web site at,
http://www.amsat.org