AMRAD OSCAR (AO-27)
AO-27 is an amateur satellite constructed by the Amateur Radio Research and Development Corporation (AMRAD) at the facilities of Interferometrics in McLean, Virginia. It was originally designed as a commercial satellite known as EYESAT-1 but its completion was halted part way through the project. An agreement was made for AMRAD to finish the construction of the satellite and add an amateur satellite transponder. 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.
Name AO-27 NORAD 22825 COSPAR designation 1993-061-C Inclination (degree) 98.251 RAAN 190.750 Eccentricity 0.0008681 ARGP 171.364 Orbit per day 14.29136207 Period 1h 40m 45s (100.75 Min) Semi-major axis 7173 km Perigee x apogee 788 x 801 km Drag factor -0.000009537 1/ER Mean Anomaly 188.766
436.795 MHz (FM)
145.850 MHz (FM)
Mode and Antenna Polarization:
Inactive, FM repeater – Telemetry transfer over Italy
Latest information: October 18th, 2012 We tried to do a restart of the high level code today which did not work out. We left the transmitter on to drain the batteries in hopes of clearing any latch ups. On the next pass, we could turn the bird back on so it survived the battery draining. The modem problem was back and we got that cleared. Its back up on the secondary bootloader. Michael, N3UC AO27.org