All posts by scsprogramme

Desesperately seeking Sputnik

In earlier posts, we discussed about our geostationary station facilities.

Now it is time to take care of the low earth orbit (LEO) station that is operated together with ISAE.

With Jérémie C., my colleague from ISAE, we spent a couple of hours re-aligning the antennas of the LEO station. Some refurbishing work on the building roof called urgently for a re-alignment.

It basically boils down to the following steps:

  1. Using the antenna controller, align the antennas with E=0 and Az=0 (according to the vu-meters).
  2. Check with a compass whether the antennas are truly flat and pointing to N.
  3. If not, align mechanically the antennas. This might involve climbing on the mast 🙂
  4. Using the antenna controller, point the antenna “full scale” (E=180, AZ=360).
  5. Check with a compass whether the antennas are truly flat and – again – point to S.
  6. If not, align the scale of the VU-meters with the fine tuning knobs on the controller and go back to step 5.

Now, keep in mind that the antenna aperture is large enough (> 30°) to accommodate for rough (i.e. handed compass) alignment.

Enough  text, here are some snapshots !

Up and running

This is an official disclaimer: our satcom lab is now up and running.

At 18:00 (UTC+1), we have finalised the installation of all our antennas on the building roof. It all started in the morning with the preparation of the roof for hosting the auto-pointing antenna kindly donated by the French Space Agency (thank you !). And also a big thank you to the logistics department of ISAE for giving us a helpful hand on that.

Preparing for installation
Preparing for installation

The afternoon was busy with lectures, so 5PM was the earliest slot for resuming antenna setup operations. At 6PM we were done and ready for testing.

November 6, 2015 at 6PM. We're ready for testing
November 6, 2015 at 6PM. We’re ready for testing

It turned out that everything was running smooth and ZDF was on the screen directly received from Hotbird 13 (this has still to be verified though … it’s pretty crowed over there and every satellite is keen on broadcasting ZDF)

ZDF is now on the screen. We're up and running
ZDF is now on the screen. We’re up and running

A last look through our IP cam (I still have to figure out how to turn IR “on”) and it is a goof time for stowing the antenna and enjoying the week-end

Our drive away IGP antenna as seen from the IP Cam
Our drive away IGP antenna as seen from the IP Cam


Today (4th of November) was a hot day. Especially on the roof of our offices in Toulouse.

Time for some videoconferencing with 1st year students from Télécom Bretagne located in Brest. To make it a little bit spicier, I wanted to set up a temporary satellite access and have the videoconference go through it.

Mischief managed !

We’ve moved !

Last July we have moved to another building … so did the lab.

Our new lab room features more space and a short access to the roof … call it antennas heaven. And we’re almost done with the deployment of the antennas : done with the 1.2 m Ku band, done with the 0.6 m Ku band, done with the 0.75 m Ka band for Internet access !

The one missing (the big box on the picture below) is the 1.2 m auto-pointing Ku antenna. Expect news soon.

The lab antennas
The lab antennas

DVB-S2 – reloaded

We have extended our DVB-S2 experimental facilities with two brand new modems.

These two Newtec MDM 6000 are joining the two Newtec Elevation 470 we already had. They feature DVB-S/S2/S2x + ACM and a BB Frame over IP capability to enable external decoding of the baseband frames.

Below, a snapshot of the setup.

Two DVB-S2x modems read y for use
Two DVB-S2x modems ready for use

And just below the modems, we’ve also added two PC-based network appliances. They will host the performance enhancement proxies for speeding up TCP trafic.

Link budget is all you need

Students are now out for internship and I haven’t had the time to talk about their projects.

Here is one interesting exemple. Anna and Ederson have developed a link budget tool for geostationary satellites. It is written in LabVIEW and named “SatLinkTool”.

A snapshot from SatLinkTool
A snapshot from SatLinkTool

Their report is available from the project forge that is kindly made available by ISAE. The report includes a link to their defence presentation should you need a short overview.

Besides, if you are interested, drop me a line (Laurent Franck at Telecom Bretagne), the files are available.

Internet is with us

Looking back over the past 18 months, I’m struck by the major leap we achieved in terms of field experimental facilities. To summarise : our lab is now going outdoor.

The last (?) piece of this puzzle is our brand new Internet access via satellite.

Satellite based Internet ready for field use
Satellite based Internet ready for field use

It was made possible thanks to the generosity of SES. Let them be thanked.

This Ka-band internet access is a perfect match with the multi-service terminal that was integrated by our students. Wired and wireless Internet , wired and wireless VoIP telephony.  All packaged in a ruggedised 19″ rack with a UPS.

Ruggedised multi-service terminal
Ruggedised multi-service terminal