maroc-tubsat

It's quite interetsing to investigate  a strange satellite. In 2002 I was looking at data waveforms from orbiting satellites- here is the intruder MAROC-TUBSAT, which appeared unannounced in the amateur bands (now switched off).

Info is in reverse order as it was updated.

NEWS JUST IN (27 Jan 2002):

on the amsat-bb there is an account of a conversation between a German radioamateur and the professor of the Technical University of Berlin, as follows:


"MAROC-TUBSAT is a joint project of TUB and a Moroccan group at Rabat. This group was responsible for the choice of frequencies. They told him, that they were radio amateurs, and the frequencies were OK and coordinated. He relyed on their word.


The 144.100 MHz downlink is a beacon, which was implemented to support tracking of the satellite and enable discrimination of the correct object in the NORAD data. The text transmitted was CN for Morocco , a name and some text in Arabic, and some CW phrase, which he was told as beeing used in Ham Radio.


Prof. Renner received lots of complaints about this transmission on 144.100 MHz from radio amateurs, especially from Australia. From this he learned, that there must be something wrong with using this frequency. He immediately urged the Moroccan team to switch off this downlink then, and they did so. Prof. Renner repeatedly told me, that he feels very sorry for interfering the radio amateurs.


The command channel of the satellite is 436.075 MHz. This is an up- and downlink. The downlink is not active permanetly; it only responds, when the command stations are sending any commands. There are two command stations: one in Berlin, Germany, and one in Rabat, Morocco. So it should be possible to hear the 70 cm downlink within a circle around Berlin and Rabat only, whenever these cities are in view of the satellite.


... He again told me, that the Moroccan group told him, that they were radio amateurs, and all this was OK within the rules of amateur radio. The head of the Moroccan group is a high-rank General in the King's staff. His name is Benslimane. Callsign is unknown to TUB.


I'd like to emphasize, that Prof. Renner spoke with me in a very constructive and agreeable way. He several times said, that he obviously was bad-advised and he regrets the problems caused to the radio amateurs. He feels very sorry about this."

Click below to download .WAV file of 436.075 MHz data file believed to be from MAROC-TUBSAT. Recording made January 24th 2002 at about 20:38 utc. g0sfj.wav


Here are 3 pictures of the waveform. Picture 1 shows that one of the sequences (this is the last burst in the .Wav above) begins with a 3 second burst centred at 900 Hz and with 300 Hz harmonics. Picture 2 shows another type of data burst (the one before) starts with a diifferent tone setup and Picture 3 shows the data itself at 0.01 seconds - 16 bits .

 A correspondent on amsat-bb suggests that the last waveform is BPSK modulated at 1600Hz.
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Download another short .WAV file from 436.075, 25.Jan.02

Download my cleanest recording, .WAV file from 436.075, 26.Jan.02 (satellite probably under the control of Rabat)  LARGE FILE


 

Finally, here is the fast Fourier Transformation of the "CW" on 144.100 from Maroc-Tubsat. The message was: VVV DE CN / ZARKAA AL YAMAMA Notice the 1200 Hz tone and harmonics, also a little transmitter "fingerprint" at 3195 Hz




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