Signals from the Soyuz/Fregat stage launched from Kourou

Sven Grahn


First launch in 2011

I found the frequencies for the Fregat stage for Soyuzes out of French Guiana by consulting Starsem's manual for the rocket available on-line. It gave two numbers: 2218.0 MHz and 2227.0 MHz. I toggled between the two frequencies. The launch took place at 1030.26 UT on 21 October 2011. I toggled between the two frequencies every 5 seconds or so. As I switched to 2218.0 MHz at 1053.16 UT the strong signal was there - see the waterfall spectrum below. I used my vertical 3.5-turn helix as usual.

I captured one more good waterfall spectrum before the signal faded out about 1056 UT: The vertical straight lines are interference.

Second launch in 2012

The rocket with the second batch of Galileo test satellites took off from Kourou at 1815:01 UT on 12 October 2012. This time I had changed the bandwidth of the spectrum display to 150 KHz to be able to see details of the signal spectrum. Very strong signals appeared on 2218.0 MHz at 1835:58-1839:04 UT. As usual I used the 3.5-turn vertically oriented helix to receive the signals. The map below shows the approximate ground track. The maximum elevation during my reception was probably about 45. The Fregat upper stage nominally ignited 10 minutes 24 sec after launch, i.e. at 1825:25 UT. Its first shutdown occurred 23 in 31 sec after launch, at 1838:32 UT, i.e. during my reception. The vehicle was observed visually by Nils von Storch from the Netherlands and I too should have been able to see it fly by under propulsion - if I had only thought about it! That is also the reason for the inaccuracy of the map below - the vehicle  was under rocket power.

The FM demodulator was switched on during this reception and also recording of the sound. The signal bandwidth was about 30 kHz.

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