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fahnen/10.jpg Amateur Satellite Summary - PoSAT-OSCAR 28
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PoSAT-1 (PO-28)PoSAT-OSCAR 28 

Satellite Summary

Name: PoSAT-OSCAR 28 (PoSAT-1)
Catalog Number: 22829
Callsign:Broadcast: POSAT1-11BBS: POSAT1-12
Launched: September 25, 1993
Launch vehicle: Ariane
Launch location: Kourou, French Guiana
Weight: 48.7 kg
Orbit: Circular LEO (Low Earth Orbit), sun synchronous, initially 822 x 800 km ( currently 799 x 783km)
Inclination: 98.6 degrees
Size: 350 x 350 x 650 mm
Period: 101 Minutes

Digital Transponders Mode JD 9600 baud FSK (FM)

  • Uplinks:
    • 145.925 MHz
    • 145.975 MHz
  • Downlinks:
    • 435.250 MHz
    • 435.275 MHz
  • Commercial Downlink:
    • 429.950 MHz
  • Similar to KITSAT-OSCAR-23 in construction.
  • 9600 bps AX.25 protocol store-and-forward PACSAT Protocol Suite communications system.
  • 38k4 bps downlink capability
  • CCD Earth Imaging System (EIS)
  • Star Sensor
  • GPS Navigation Experiment
  • Cosmic Ray Experiment (CRE)
  • Digital Signal Processing Experiment (DSPE)


Launched alongside HealthSat-2 on the September 1993, PoSAT-1 is Portugal's first satellite achieved through a technology transfer program with Surrey Satellite Technology, Ltd. (SSTL).  PoSAT-1 was built at the University of Surrey in a collaborative program between a consortium of Portuguese academia and industry.  The Portugese consortium sent 4 engineers to Surrey to participate in on-the-job training.  Like KITSAT-1, PoSAT-1 carries a wide range of technology experiments, including earth imaging cameras, DSP and space-radiation experiments. In addition, PoSAT-1 carries the first microsatellite GPS experiment and an ultra-low-cost CCD star sensor. PoSAT-1 is operated jointly by the University of Surrey command station at Guildford and the Portugese command station at Sintra.

PoSAT was operated on amateur frequencies for several weeks in early 1994.  OSCAR News 105 (February 1994, p. 35) carried a letter from CT1DBS reporting that an agreement was signed by AMSAT-PO and the PoSAT Consortium on December 6, 1993 stating "The name of PoSat-1, when in use by the amateur radio community will be PoSAT OSCAR 28, OSCAR 28 or PO-28."   Presently, PoSAT-1 is not open for amateur operations, however a recent agreement with AMSAT-UK will return PoSAT back to amateur use in Q3 2005.

More information is available at the Surrey Satellite Technology, Ltd. and PoSAT-1 Mission.


  • Steve Ford, "PoSAT-OSCAR 28 Opens to Amateurs,"QST, Apr 1994, p. 110.

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