Satgen278 Satellite Profile No7 Oscar Ten by GM4IHJ 23rd July 94 BID of this msg is SGEN278 Please use this BID if you retransmit this msg The maxim "Old soldiers never die. They only fade away" , certainly applies to this satellite. Battered by radiation in an orbit very different from the one planned for it. This satellite lost its onboard computer several years ago. Since when it has been uncontrolable, pointing where ever the elements push it. So it is a matter of luck whether its solar cells see enough sunlight to achieve a reasonable power level. None the less, it returns to operational status every so often , and as this is being written, there are good signals on it from Hawaii, Canada, USA, Italy and Germany, with twenty stations enjoying excellent SSB communications through its mode B transponder. Oscar 10 is in an elliptical orbit which takes it to high altitude above the earth's equatorial belt. Orbital inclination is only 27 degrees, which presently locates its apogee high point above latitude 7N. So it rarely gets to high elevation over Europe. But this can be an advantage to stations with antennas fixed in elevation. Good copy is coming into GM4IHJ on a 5 element 2m yagi trainable in azimuth feeding a pre amplifier and a FT221R receiver tuned 145.812 to 145.960 MHz with most of the SSB qsos being located between 145.89 and 145.93 MHz USB. Transmission is 50 watts of LSB to a 12 element long yagi in the band between 435.17 (for 145.835 approx downlink), and, 435.04 MHz ( to come down at about 145.965 MHz). Please note that this is frequency inversion in the transponder of the satellite, highest up = lowest down , and you must use LSB up to get USB down. Only the mode B transponder is operating. There is a beacon on 145.812 MHz , but if it is working it never sends sense, all I hear is a growling noise . It is not easy to predict when Oscar 10 will be operational. It can be dead for weeks, then gradually come back to life as it sees more sunlight for a few weeks before fading again as the sun angle on its solar cells decreases. When working as now its communications quality is good, and during the rest of 1994 its apogee will climb slowly up to 27N where given that it gets a good sun angle on its solar panels it should give excellent northern hemisphere communications. When its power supply is low, you may hear it with "wobbly" FMing signals . Please do not use it in these conditions. How long can it last ? Oscar 10 is 11 years old - so we have already had our money's worth twice over. Sooner but more likely later, radiation damage to its solar cells will seriously reduce its power supplies and it will cease to be operational. But at present in July 94, there is no sign of a major drop in its signal output. It could be in good shape for several more years yet to come. So if you have never tried it, or been put off phase 3 satellites by Oscar 13s spin modulated downlink, please have a listen to Oscar 10. When the sun is shining on this excellent old timer it is a very useful satellite indeed. 73 de John GM4IHJ @ GB7SAN