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.