AMRAD-OSCAR
27
Satellite
Summary
Name: AMRAD-OSCAR 27 aka EYESAT-1
NASA Catalog Number: 22825
Launched: September 26, 1993
Launch vehicle: Ariane 4
Launch location: Kourou, French Guiana
Weight: 11.8 kg
Orbit: Polar LEO (Low Earth Orbit)
Inclination: 98.5 degrees
Size: 150 x 150 x 150 mm
Period: 101 Minutes
Uplink:
Downlink:
Features:
-
Amateur payload combined with an experimental payload.
-
EYESAT-1 is an experimental Microsat satellite built by Interferometrics
Inc, of Chantilly, Virginia.
-
The amateur equipment onboard the satellite was built by AMRAD.
-
For further information about AMRAD contact:
Status: Semi-Operational
Description
AMRAD/EYESAT-1 was one of six satellites that was launched together on
a Ariane V59 rocket from French Guiana at approximately 0147 UTC, 26 September
1993. The amateur payload of EYESAT-1 was later designated AMRAD-OSCAR
27 once in orbit. The launch included the German Stella Laser Reflector,
Healthsat-II,
PoSAT-1, and
amateur satellites KITSAT-OSCAR-25
(KO-25) and
Italy-OSCAR-26
(IO-26).
AO-27 is a secondary amateur communications payload carried aboard the
EYESAT-1 experimental MICROSAT satellite built by Interferometrics Inc.
of Chantilly, Virginia. The commercial side of the spacecraft's mission
is the experimental monitoring of mobile industrial equipment.
The amateur equipment aboard the satellite was constructed by members
of AMRAD, a technically oriented, non-profit
organization of radio amateurs based in the Virginia suburbs of Washington,
D.C., to meet the needs of amateurs for a platform to conduct digital satellite
communications experiments.
AO-27 is an "FM Repeater" in space. It essentially consists of
a crystal controlled FM receiver operation at 145.850 MHz and a crystal
controlled FM transmitter operating at approximately 436.795 MHz.
Output power of the transmitter can be set to over 1 watt (rarely used),
0.5 watts (normal operation), or under 0.1 watts (exciter only).
The uplink antenna is the linear polarized whip on the top face of the
spacecraft and is shared with the commercial payload's receivers.
The downlink antenna is a 1/4 wave whip mounted on the bottom face of the
spacecraft. Polarization is nominally linear, the rotation and revolution
of the spacecraft and propagation effects will cause the actual signal
polarization at a ground station to vary widely during a pass.
Because of the satellite's limited power budget and a desire to maintain
sufficient battery capacity for as many years as possible, the amateur
transmitter on AO-27 is on for only part of the daylight portion of each
orbit. As of September 1998, the satellite passed its five year design
goal with minimal signs of battery degradation, so this operating philosophy
appears to have been successful.
AO-27 is available on daylight passes over the Northern Hemisphere.
The "TEPR" States describe the amount of time (in minutes) when the spacecraft
enters and leaves sunlight. TEPR numbers are adjusted every few months
to account for the seasonal North/South movement of the latitudes where
AO-27 enters and exits sunlight. Chuck Wyrick, N1UC (formerly KM4NZ), provides an
Explanation of TEPR States. Most tracking
programs will provide a reading or display the necessary info to predict
if AO-27 will be "on" during a pass.
More information on AO-27's schedule and operation
courtesy of Michael Wyrick, N4USI, the control operator of AO-27 and Steve
Greene, KA1LM.
[Special thanks to Stephan Greene, KA1LM, for assisting in the above
information -- N7HPR]
References
-
John Hansen, "New Satellites in Orbit," The AMSAT Journal, Vol.
16, No. 5, Sep/Oct 1993, p. 1.
-
Steve Ford, "AMRAD Oscar 27," QST, Dec 1993, p. 107.
Last update May 31, 2003 - N7HPR