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73 Amateur Radio Today ■ February, 1991 79

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Amateur Radio Via Satellite

Photo B. Mark Attery G7DSY at the UoSAT control station at the University of Surrey, (N5FVM photo)

Photo B. Mark Attery G7DSY at the UoSAT control station at the University of Surrey, (N5FVM photo)

Andy MacAffister WA5ZIB 14714 Knightsway Drive Houston TX 77083

The Satellite Programs

Most universities do not build their own spacecraft Until 1979 the University of Surrey in England was no exception. British university involvement prior to 1979 concentrated on the development of sensor systems, instrumentation, and detectors for experiments on board satellites boift by industry.

Dr. Martin Sweeting G3YJG recognized an opportunity to expand the involvement ol the University of Surrey to Duild small, low-cost spacecraft. Offered a launch opportunity by the United Slates, he and a small group of researchers in Surrey built not only satellite subsystems, but a whole satellite with rts own power systems, experiments, control circuits and transmitters.

The goat was to create a satellite that could be monitored using simple systems on ham radio frequencies. The experiments were to be complex enough to stretch the abililies of university students, but still keep the emphasis on making the system oulput useful for educators at air grade levels, as well as for amateur radio operators. Experiments included a magnetometer, radiation counters, a chargecoupled device (CCD) camera, and an array of shortwave propagation beacons.

As Martin pointed out. today's school children are tomorrow s university studenls. and eventually our future spacecraft engineers.

Photo A. This fit-check" model of U-O-11 {launched 7 years ago) sits quietly in a lab at Surrey. (N5FVM photo)

UoSAT-1

UoSAT-1, also known as UoSAT-OSCAR-9. was launched by NASA on October 4( 1981, from the Vandenberg Air Force Base in California with the Solar Mesopheric Explorer. The faunch vehicle was a Delta rocket For the first days of its life, U-O-9 sent only an unmodulated carrier. Finally on October 9, 1981. the staff at Su;rey managed to command U-O-9 to the 300 baud ASCII downlink mode. Until its fiery end in the atmosphere on October 13, 1989, U-O-9 sent telemetry etther digitally via RTTY, CW or ASCII, or through the digital speech synthesizer system detailing the status of onboard sensors and experiments. The mission proved the viability of a university-inspired satellite program and generated interest from academic, technological industrial and commercial sectors.

The success of the UoSAT-1 program encouraged G3VJO anc others to continue with small satellites and to develop UoSAT-B., which would become UoSAT-2 or UoSAT-OSCAfVI1 after launch. The U-O-11 mission was to fly a proofof-concept digltai store-and-forward communications experiment prior io a dedicated packet satellite spacecraft, and to use a launch opportunity made available by NASA

The LANDSAT-4 Earth resources satellite needed to be replaced The University of Surrey was officially informed of an opportunity in September 1983 for a ride to space in March 1984.

UoSAT-2

With only six months available, the team in England designed, fabricated, assembled, integrated and tested UoSAT-2, and were ready for another California launch from Vandenberg Air Force Base on March 1. 19S4. Harold Price NK6K spent much of that time in Surrey living in Spartan conditions working with the Surrey team. The ride lo orbit with LANDSAT-5 was uneventful, but only a day later ihe satellite would no! respond to commands sent from th e con t ro f stai io n After 10 we e ks of intensive effort in England and at the Stanford Research institute in California. U-O-n was once again responding to commands and transmitting telemetry on 2 meters.

A logic gate had failed only hours after deployment, bul the problem was not easily diagnosed from Ihe ground,

U-O-11 fs still rn orbit and functioning. It is usually configured! for 1200 oaud telemetry on 145.825 MHz FM. The 350 mW 2 meter beacon can t>e heard successfully on most portable and mobile rigs. An old Bell 202-type modem with a simple modification to invert bit sense (" to "0" and "0" to "I") can provide the listener with plenty of telemetry to decode. Like U 0-9. U-O-11 has a speech synthesizer, a CCD camera, and several modes lor the telemetry downlink. U-O-11 also has a particle-wave experiment, a space-dust detector, and the Digital Communications Experiment(DCE)

UoSAT-3 and -4

On January 22t 1990, the University of Surrey added two more satellites to Its continuing list of accomplishments.

Photo C. Main University of Surrey safe/We tracking antennas on a modified antiaircraft gun mount. (NSFVt- f oho to)

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