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ARRL Satellite Bulletin ARLS017 (2001)

ARLS017 AO-40 Gives Earthlings Another Scare

QST de W1AW  
Space Bulletin 017  ARLS017
From ARRL Headquarters  
Newington, CT  August 29, 2001
To all radio amateurs

ARLS017 AO-40 Gives Earthlings Another Scare

Sighs of relief were heard around the world as the 2.4-GHz S2 beacon
aboard the AO-40 satellite reappeared August 28 after an ominous
absence. The beacon failed to return on Orbit 381 at MA=44 (MA, mean
anomaly, an orbital position), when the RUDAK connections shut off
as programmed.

Gunter Wertich, DF4PV, who is equipped for moonbounce work, reported
hearing normal telemetry blocks very weakly, however, so ground
controllers were assured that the onboard computer had not crashed.
''It was suspected that the solid-state matrix IF connections had not
latched properly during the switch-over at MA=44,'' said ground
controller Stacey Mills, W4SM, who suspected DF4PV was hearing
middle beacon ''bleed through'' via the IF matrix.

When the satellite came into view at Mills' Virginia location, he
manually cycled the middle beacon-to-S2 transmitter connection off
and on, ''and the middle beacon popped back up,'' he said.

Although the RUDAK is temporarily turned off, Mills said the
schedule will remain in place. For now, there will be no middle
beacon and no RUDAK from MA=30 to 44. The middle beacon is off from
MA=220-250 because of eclipses.