Register Account

Login Help

ARRL Satellite Bulletin ARLS009 (2001)

ARLS009 AO-40 transponder tests a hit!

QST de W1AW  
Space Bulletin 009  ARLS009
From ARRL Headquarters  
Newington, CT  May 8, 2001
To all radio amateurs

ARLS009 AO-40 transponder tests a hit!

The inaugural AO-40 transponder tests have been a huge success.
Reports from amateurs making their first contacts on AO-40 have come
from all over. More are expected as the experimental operation

''It was just great!'' enthused AMSAT-NA President Robin Haighton,
VE3FRH, who worked a dozen or so stations via AO-40 over the

AO-40 ground controllers opened up the next-generation satellite's
transponders May 5 for general amateur use on an experimental basis.
Stations can uplink on either 435 MHz or 1.2 GHz. The transponder
downlink is at 2.4 GHz. The operation is experimental, the schedule
subject to change, and the transponders could be shut down at any
time without warning.

Mike Seguin, N1JEZ, in Vermont, was first to report his contacts on
the AMSAT bulletin board. ''I've successfully logged a dozen contacts
in the first hour of operation, including two contacts using the
Mode-L uplink,'' he said. Seguin said his final tally was 24
contacts, including QSOs with Europe. ''A great first day! Let's hope
for many more.''

Ed Krome, K9EK, in Indiana, echoed N1JEZ's comments. ''Wow, AO-40 was
terrific on this first morning of transponder operation,'' he said.
''After almost 10 years, what a thrill!''

AO-40 may be available for use several hours a day, starting at MA
136 and continuing through MA 240. During the weekend passes, the
transponders were available for six hours or so from a given point
on Earth.

The tests have shown that uplink frequencies (without taking Doppler
into account) are 435.495-435.780 MHz and 1269.211-1269.496 MHz, and
the downlink passband is 2401.210-2401.495 MHz. The transponders are
inverting, so a downward change in uplink frequency will result in
an upward frequency shift in the downlink.

Users are being asked to avoid the ''middle'' telemetry beacon at
2401.323 MHz and give it a clearance of 5 kHz on either side. For
maximum QSO signal strength, stations should aim for a passband
signal that's 10 dB below that of the middle beacon.

Following the transponder experiment, ground controllers plan to
raise AO-40's perigee by approximately 200 km.


Instragram     Facebook     Twitter     YouTube     LinkedIn