INMARSAT: Decoding 12 Aero-channels in parallel
Action: Free software allows for decoding twelve INMARSAT in parallel
A recent post in Carl’s rtl-sdr-blog informed about the ebay-lability of some surplus Outernet patch antennas for just – see here. For just 29 US-$, I got this small antenna with integrated SAW filter (1525 – 1559 MHz) plus LNA. A real bait for me to jump over the limit of 30 MHz reception! Soon I fired up my AirSpy R2 receiver, providing the LNA with power supply (Bias-Tee). It worked fine, and I received a whole bunch of excellent signals by this setup.
As I wanted to receive some aircraft information, so I downloaded free JAERO decoder of Jonathan “Jonti” Olds, also from New Zealand. This fine software can be opened in many instances. In combination with the up to 24 decoders of SDR-Console V3 of Simon Brown, this modest setup turned into a multi-channel satellite reception post.
Here 12 decoders had been assigned – one on each INMARSAT channel. You see also quite good SNRs from the Outernet patch antenna.
Next steps worked as usual with the mutli-channel approach:
- make up 12 channels in SDR-Console and tune each channel to a different signal. Mode must be USB, and as bandwidth I choose 1200 Hz for 600 bps and 2400 Hz for 1200 bps channels. That’s a bit wider than necessary, but doing so there is some room for the AFC in JAERO decoder always to stick to the signal even if the SDR should drift a bit over 24 h or so
- The output of each channel is then routed to a different Virtual Audio Cable, or VAC 1-12.
- Then you have to install twelve instances of JAERO software in different folders, e.g. JAERO 1-12. You should name each JAERO.exe file accordingly, e.g. JAERO_1.exe to JAERO12.exe.
- Open JAERO_1.exe, assign its input to VAC 1, and set the matching speed of the signal. If all is ok, you will be rewarded by a sharp phase constellation, and soon decoding will start.
- Repeat the above steps until you have reached JAERO_12.exe, connected to VAC 12.
The “Matrix” of SDR-Console V3 shows the twelve channels with different signal strengths and width, depending on the data rate (600bps/narrow, 1200bps/wide).
The result can bee seen from the screenshot at the top of this page. The whole setup ran stable and unattended for hours.
Thanks for all smart people having developed the smart software and hardware!
Nils Schiffhauer – DK8OK 
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Do you have video of this receptions ?
Hi, Alex – thanks for your mail! Sorry, I don’t have videos about that. Found it too much time-consuming to make a really instructive (!) video. This would take me half a day or so which I can invest better for new things. But, as you asked, I see there is a demand for such support. So I may return to making videos again if I have more time. 73 Nils, DK8OK
Sorry, no. 73 Nils, DK8OK
Pingback: Decoding 12 AERO Channels Simultaneously with an Airspy, Outernet Patch Antenna and SDR-Console V3
Hi can you tell me how to point the antenna in the the right direction and which inmarsat frequency this is? Newbe here 🙂
… you may see the frequencies from the screenshots by zooming, around 1545,050 MHz. Just point the flat antenna towards a position where also TV satellite dishes point to. It is not that critical, but should be ner 15°4 W, the position of INMARSAT 3F2. Then move left and right, and tilt it a bit. the tilt angle should be the same that of your geographical latitude (ca. 52°, I presume …). 73 Nils, DK8OK
The site http://www.rtl-sdr.com said https://www.rtl-sdr.com/decoding-12-aero-channels-simultaneously-with-an-airspy-outernet-patch-antenna-and-sdr-console- v3 / and the “Display-Launcher” program was used, can you explain how you connected Jaero and D_L? thanks
… by Virtual Audio Cable (VAC) … You have to work with multi-instances with VAC and Decoder. 73 Nils, DK8OK
I use SDRConsole and VAC to transfer the signal to Jaero but I cannot figure out how to transfer data from Jaero to Display-Launcher
… see http://www.agenetools.com/downloads/Display-Launcher.pdf from p.9. With JAERO, it should go the same way. It was some time ago, I tried this out. Have to repeat it again if there is time … There is also an HFDL Yahoo Group with some smart people, among them the author of Display Launcher. 73 Nils, DK8OK