Signals from MAROC-TUBSAT

Sven Grahn

On 23 January 2002, the word spread around the world about an "intruder" on the 144-146 MHz amateur band. Space listener's quickly identified the satellite as MAROC-TUBSAT, launched 10 December from Baikonur in Kazakhstan on a Zenit-2 rocket. The satellite has the international designation 2001-56D and is in an orbit with an inclination of 99.6 degrees, a period of 105.2 minutes and an altitude between 986.8 and 1015.5 km.

The signal

I easily  picked up the signals from MAROC-TUBSAT on 23 January 2002 at 1956.45-2012.15 UT. The signal is on for 30 seconds and off for 30 seconds. The signal is narrow-band FM with an audio tone (1172 Hz) keyed on/off to represent Morse code characters (see image below map).  (Listen here, RealMedia file 68 kB). The S-meter on my Icom R-100 went to full scale deflection! Here is a map of the pass near Sweden.

The message from the satellite

The message reads VVV DE CN/ZARKAA  AL YAMAMA.

The CN is the ITU prefix for Morocco as many have noted. This makes sense since the satellite was built for the Royal Centre for Remote Sensing in Morocco by the Technical University of Berlin. I have visited the control centre for the satellite in the capital Rabat a couple of years ago. It is a very nice facility. Concerning the words "Zarkaa Al Yamama", an Arabian-speaking friend of mine says that this a woman's name . It could also be a name of a boat, a ship or a monument. But mainly this is a woman's name. So, maybe this is the name of the satellite!

I received more information from the AMSAT Bulletin board via  Jeff Brower:

I think the name makes sense when you think of the fact that the satellite is a remote sensing satellite!

The frequencies used

Originally, Morocco filed the following frequencies with the ITU.

143.625 MHz  (same as voice from ISS and Mir!!)
436.075 MHz
2208.0 MHz

I really listened hard for signals on the two lower frequencies soon after launch but heard nothing. Has anyone heard it on those frequencies?

The presently used frequency appears to be a violation of international agreements on how to use the 144-146 MHz radio amateur band (the so-called 2 meter band). The OSCAR satellite sub-band is  145.8-146.0 MHz.  Morocco is an IARU member (International Amateur Radio Union) and should be well aware of this. 2-m band planning gives 144.05-144.10 for general CW and weak signals and 144.10-144.20 for Earth-Moon-Earth transmissions and weak signal Single Side Band (SSB) communications.

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