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Decoding the QO-100 beacon with gr-satellites

On February 14, the Amateur transponders on Es’hail 2 (which now has the AMSAT designation QO-100) were inaugurated. Since then, two beacons are being transmitted by the groundstation in Doha (Qatar) through the narrowband transponder. These beacons mark the edges of the transponder. The lower beacon is CW, while the upper beacon is a 400baud… Continue reading Decoding the QO-100 beacon with gr-satellites

DVB-S2 GRCon23 CTF challenge

This year I submitted a challenge track based around a DVB-S2 signal to the GRCon CTF (see this post for the challenges I sent in 2022). The challenge description was the following. I was scanning some Astra satellites and found this interesting signal. I tried to receive it with my MiniTiouner, but it didn’t work… Continue reading DVB-S2 GRCon23 CTF challenge

ldpc-toolbox gets LDPC decoding

Recently I have implemented an FPGA LDPC decoder for a commercial project. The belief propagation LDPC decoder algorithm admits many different approximations in the arithmetic, and other tricks that can be used to trade off between decoding sensitivity (BER versus Eb/N0 performance) and computational complexity. To help me benchmark the different belief propagation algorithms, I… Continue reading ldpc-toolbox gets LDPC decoding

Decoding the Artemis I Orion vehicle

On Wednesday 16th, the Artemis I mission was launched from Kennedy Space Center. This mission is the first (uncrewed) flight of the Orion Multi-Purpuse Crew Vehicle that will be used to return humans to the Moon in the next few years. Together with Orion, ten cubesats with missions to the Moon and beyond were also… Continue reading Decoding the Artemis I Orion vehicle

Trying to observe the Vega-C MEO cubesats

On July 13, the Vega-C maiden flight delivered the LARES-2 passive laser reflector satellite and the following six cubesats to a 5900 km MEO orbit: AstroBio Cubesat, Greencube, ALPHA, Trisat-R, MTCube-2, and CELESTA. This is the first time that cubesats have been put in a MEO orbit (see slide 8 in this presentation). The six… Continue reading Trying to observe the Vega-C MEO cubesats

Measuring the Allan deviation of a GPSDO with an SDR

A few days ago I tried to measure the QO-100 NB transponder LO stability using my DF9NP 10MHz GPSDO. It turned out that my GPSDO was less stable than the LO, so my measurements showed nothing about the QO-100 LO. Carlos Cabezas EB4FBZ has been kind enough to lend me a Vectron MD-011 GPSDO, which… Continue reading Measuring the Allan deviation of a GPSDO with an SDR