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ARRL Satellite Bulletin ARLS011 (2004)

ARLS011 AMSAT "Echo" Satellite to Open for FM Voice Trial Run

QST de W1AW  
Space Bulletin 011  ARLS011
From ARRL Headquarters  
Newington, CT  July 29, 2004
To all radio amateurs

ARLS011 AMSAT "Echo" Satellite to Open for FM Voice Trial Run

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,, 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

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,


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