Tracking NOSS 3 from Sweden


Sven Grahn

On December 31,2007 I decided to make a survey of SGLS channel 7, i.e. 2232.5 MHz, and rather quickly found that the LEO satellites that I was receiving all belonged to the NOSS 3 series. The blue crosses in the table below represent frequencies that were listed on the UHF-SATCOM web site at the end of 2007. The red cross is my addition to this table.
NOSS
 2222.5
 2232.5
 2277.5
3-1
 x
 x
 x
3-2
 x
 x
 x
3-3
x
3-4
 x



The satellites NOSS 3-1 and 3-2 transmit on every pass over my horizon, while NOSS 3-3 only transmitted on the easternmost pass over my horizon on 1 and 2 January. Why it exhibits this weird behaviour is not clear at this moment. Perhaps it switches to another frequency. I will check this in the near future - hopefully. The pass of NOSS 3-3 is shown below.



However, on 3 January 2008 NOSS 3-3 transmitted in the  two easternmost passes. But the signal was commanded off. It is my impression that otherwise the transmitters on the NOSS satellites are transmitting continuously.

Below is an example of  part of the frequency survey of 2232.5 MHz on January 2, 2008. I have coloured the carrier dots (the display updated every 60 seconds) yellow for clarity. Near closest approach a general "mist" is visible on the display. This is probably the result of wideband telemetry.



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