[HamSat] AO-7 Alive!

[Tim Pickett]

AO-7 is alive alter all these years! Receiving reports from all over the
world on hearing AO-7, and people using the transponder! Here is a bit of
info on AO-7:
73... Tim KG8OC
AMSAT-OSCAR 7
AMSAT-OSCAR 7 was launched November 15, 1974 by a Delta 2310 launcher from
Vandenberg Air Force Base, Lompoc, California. AO-7 was launched piggyback
with ITOS-G (NOAA 4) and the Spanish INTASAT. The second phase 2 satellite
(Phase II-B). Weight 28.6 kg. Orbit 1444 x 1459 km. Inclination 101.7
degrees. Octahedrally shaped 360 mm high and 424 mm in diameter. Circularly
polarized canted turnstile VHF/UHF antenna system and HF dipole.
Firsts: Satellite-to-satellite relay communication via AO-6; Early
demonstrations of low-budget medical data relay and doppler location of
ground transmitters for search-and-rescue operations were done using this
satellite.

Similar to AO-6. Built by a multi-national (German, Canadian, United States,
and Australian) team of radio amateurs under the direction of AMSAT-NA. It
carried Mode A (145.850-950 MHz uplink and 29.400-500 MHz downlink) and Mode
B (432.180-120 MHz uplink and 145.920-980 MHz downlink (inverted)) linear
transponders and 29.500 and 145.700 MHz beacons. The 2304.1 MHz was never
turned on because of international treaty constraints. Four radio masts
mounted at 90 degree intervals on the base and two experimental repeater
systems provided store-and-forward for morse and teletype messages
(Codestore) as it orbited around the world. AO-7 was operational for 6.5
years until a battery failure ceased operation in mid 1981.

References:

  a.. K1ZND, "Oscar News: Oscar 7 - It Works!," QST, Jan 1975, p. 49.
  b.. Joe Kasser and Jan King, "OSCAR 7 and Its Capabilities," QST, Feb
1974, p. 56-60.
  c.. Perry Klein and Ray Soifer, "Intersatellite Communication Using the
AMSAT-OSCAR 6 and AMSAT-OSCAR 7 Radio Amateur Satellites," Proceedings of
the IEEE Letters, Oct 1975, pp 1526-1527.
  d.. D. Brandel, P. Schmidt, and B. Trudell, "Improvements in Search and
Rescue Distress Alerting and Location Using Satellites," IEEE WESCON, Sep
1976.
  e.. J. Kleinman, "OSCAR Medical Data," QST, Oct 1976, pp 42-43.
  f.. D. Nelson, "Medical Relay by Satellite," Ham Radio, Apr 1977, pp
67-73.
  g.. Martin Davidoff, "Predicting Close Encounters: OSCAR 7 and OSCAR 8,"
Ham Radio, Vol. 12, No. 7, Jul 1979, pp 62-67.