[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)

[Peter Horvath]

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