Tag Archives: L-Band

Blue Force Tracking on Inmarsat

Blue Force Tracking is a GPS-enabled system that give US Military the location of “friendly” military forces. You can read more about it on Wikipedia. Inmarsat is one of the commercial satellite providers that has a contract with the the … Continue reading

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Inmarsat Antenna Distribution

Inmarsat L-Band signals from both CONUS and POR need to be routed to various receivers and SDRs, this distribution system is a pretty simple solution (as shown below). It’s based on taking an L-Band signals from a dish, where pre-amplification … Continue reading

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Aero Decoding and Full Support for HackRF One

After some work it is now possible to fully support HackRF One with my Inmarsat Aero decoder. In the past, the Inmarsat Aero decoder used two SDRs (each covering 2MHz) to cover up to 4MHz of L-Band spectrum as well … Continue reading

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Adding External Reference to HackRF One SDR

The HackRF One SDR is a great value but it’s frequency stability leaves something to be desired. Using the Si5338 clock generator from Silicon Laboratories is an easy way to address the problem (if it’s really a problem for your … Continue reading

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HackRF One and Decoders

I’m always looking for opportunities to reduce the costs associated with high quality decoding tasks. The HackRF One is intriguing because it’s not very expensive, has a wide band receiver (10MHz – 6GHz) and an SDR that is capable of … Continue reading

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Aero Coverage of POR and CONUS

The diagram below illustrates the current Aero coverage that is possible here at USA-Satcom. As you can see there is quite a bit of IQ bandwidth to deal with and consequently at least two i7 hex core machines are needed … Continue reading

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AERO-I 600 Baud GMSK

Currently there are 9 AERO-I 600 Baud GMSK channels on POR. Quite a bit of ACARS and CPDLC traffic along with the usual Call Management signaling units. These signals are huge as you can see from the “tightness” of the … Continue reading

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Aero Crypto Calls

Finally found an Aero H/H+ call that was encrypted. Supported crypto services on Aero are US-STU-III (Secure Telephone Unit), STE (Secure Terminal Equipment), FNBDT (Future Narrow Band Digital Terminal). Not clear which service this actually is but I suspect it’s … Continue reading

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Fleet Tracking on Inmarsat 4F3

Most of the popular Inmarsat activity is associated with ships and planes in AOR-E, AOR-W, POR and IOR. There is an Inmarsat satellite called 4F3 parked at 98W that gives CONUS coverage. This satellite is inclined and so does move … Continue reading

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New Inmarsat Aero-H and H+ Decoder in Development

Another new decoder project is in the works. This is another Multi-Channel decoder for Aero but instead of just ACARS and CPDLC it does AMBE and LPC voice decode. The screenshot below shows call logging status output from the prototype … Continue reading

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