Re: [amsat-bb] ANS-353 AMSAT News Service Special Bulletin - SMOG-P and ATL-1 Designated Magyar-OSCAR 105 (MO-105) and Magyar- OSCAR 106 (MO-106)
Hello,
on this happy occasion I'd like to add some more info about MO-105 and MO-106, hoping that more people will be tune in and listen to the telemetry received from the satellites.
SMOG-P (MO-105) is a 1p PocketQube (5x5x5 cm, 250 grams), a fully redundant tiny satellite with an actual scientific payload: a flying spectrum analyzer. It measures the scattered RF energy over the UHF band (specifically, in the digital terrestrial TV band) that can be detected in space. ATL-1 (MO-106) is a larger 2p PocketQube featuring the same spectrum analyzer experiment.
Both satellites transmit almost identical telemetry data. In addition to basic CW telemetry carrying callsign, battery voltage and temperature, there is a digital telemetry with variable data rate and coding scheme. Most frequently, modulation is 1250 or 5000 bps GMSK. The data is encoded either by the well-known "AO-40" FEC, or a shorter, proprietary variant of it, but they can also use a more powerful, state-of-art repeat-accumulate (RA) coding scheme.
Some practical information about receiving the telemetry: A GUI telemetry receiver is available for Windows and Linux (soon for OS X as well), and a command line receiver can also be used (Linux only). Both can be downloaded from https://gnd.bme.hu:8080/index The programs are able to submit the received packets to the central telemetry data base. This requires a quick registration, the login credentials can be used with either of the decoders. There are some issues with the GUI software that hopefully will be resolved within a few days. These decoders assume either a USB receiver connected through the sound card or an rtl-sdr receiver. Thanks to Daniel Estevez, EA4GPZ, a high quality, full decoder and packet uploader is also available for GNU Radio 3.8 within the out-of-tree module gr-satellites. For uploading to the received packets, it uses the same login as the "official" programs do: https://github.com/daniestevez/gr-satellites/tree/maint-3.8 This decoder can unleash the full potential of the RA FEC. You'll need to put an FM demodulator in front of the flowgraph. I'd be glad to see many submissions on the "Leaderboard" from around the world: https://gnd.bme.hu:8080/leaderboard Having many receiving stations around the globe could greatly improve the global picture the spectrum analyzer payload can offer. 73 Peter HA5CQA/AK4RP
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Peter Horvath