A brief try at decoding HORYU-4 1k2 AFSK telemetry
In the previous post I've talked about HORYU-4 CW telemetry. Here I report my findings when trying to decode 1200baud AFSK telemetry. Since the satellite transmits digital telemetry only over Japan,...
View ArticleSome notes on BEESAT and Mobitex-NX
The family of BEESAT satellites from the TU Berlin transmit telemetry on the Amateur bands using the Mobitex-NX protocol. Some of the BEESAT satellites also include a digipeater using this same...
View ArticleDecoding GOMX-1 telemetry
GOMX-1 is a 2U cubesat from GomSpace that was launched in November 2013 into a sun-synchronous orbit. As far as I know, it was the first satellite with an ADS-B receiver payload. It transmits telemetry...
View ArticleAISAT and ATHENOXAT-1
It turns out that the satellites AISAT and ATHENOXAT-1 use the NanoCom U482C transceiver from GomSpace. This is the same transceiver that GOMX-1 uses, so the same decoder can be used. I've added...
View ArticleConcurso QSL V-UHF
Today I've hiked to Cerro de San Pedro, SOTA summit EA4/MD-020 (1425m), to work in the last national V-UHF contest of the year: concurso QSL. This contest is a bit particular, because it coincides with...
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LilacSat-1 Codec 2 downlink
LilacSat-1 is one of the satellites that will form part of the QB50 constellation, a network of 50 cubesats built by different universities around the world that will conduct studies of the...
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Simulating JT modes: how low can they get?
In this post I'll show how one can use the signal generation tools in WSJT-X to do decoding simulations. This is nothing new, since the performance of the modes that WSJT-X offers has being thoroughly...
View ArticleReverse engineering Outernet: modulation, coding and framing
Outernet is a company whose goal is to ease worldwide access to internet content. They aim to provide a downlink of selected internet content via geostationary satellites. Currently, they provide data...
View ArticleReverse engineering Outernet: L3 and L4 protocols
This is a follow-up to my last post, where I talked about my efforts to reverse engineer the protocols used in the Outernet L-band signal. Here I will describe the L3 and L4 protocols that are used in...
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Reverse engineering Outernet: time and file services
In my last two posts, I've being talking about my reverse engineering efforts with the Outernet signal and I've described the modulation, coding and framing and the L3 and L4 network protocols used in...
View ArticleReverse-engineering Outernet in GNU Radio blog
I have published a post in the GNU Radio blog about my reverse engineered GNU Radio Outernet receiver gr-outernet. I cover more or less the same information as in a previous post in this blog, but I...
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Some measurements of CAS-2T on orbit 25
Last Thursday, a CZ-11 Chinese rocket launched from Jiuquan. Alan Kung BA1DU posted in amsat-bb some minutes after launch saying that this launch contains an Amateur payload: CAS-2T. As it is usual...
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Testing Opera sensitivity with GNU Radio
Some fellow Spanish Amateur Operators were talking about the use of the Opera mode as a weak signal mode for the VHF and higher bands. I have little experience with this mode, but I asked them what is...
View ArticleAbout KS-1Q
In a previous post, I talked about the satellite CAS-2T on a recent Chinese launch. CAS-2T was designed to remain attached to the upper stage of the rocket and decay in a few days. However, due to an...
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Testing a simple pulse generator for Linrad calibration
Lately, I've being talking with Juan Antonio EA4CYQ and Pedro EA4ADJ about performing Linrad calibration to enable the use of the smart noise blanker. They pointed me to the SIGP-1 by Alex HB9DRI,...
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Looking at BY70-1 image downlink
BY70-1 is a Chinese Amateur satellite that will launch on Monday 26 December. It has a V/U FM repeater, a camera and a 9k6 BPSK downlink on 70cm that transmits telemetry and the JPEG images taken by...
View ArticleReverse engineering Outernet talk in 33C3
If you've being following me on Twitter lately, you should already know that I've being giving a talk this morning at 33C3 about my work reverse engineering Outernet. In cased you missed the talk, the...
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First data from BY70-1
The Amateur satellite BY70-1 launched yesterday at around 3:00UTC. The launch was a partial failure, as all the satellites from this launch have been put in a 520x220km orbit. The perigee is too low to...
View ArticleKS-1Q decoded
In a previous post, I talked about my attempts to decode KS-1Q. Lately, WarMonkey, who is part of the satellite team, has been giving me some extra information and finally I have been able to decode...
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Coding for HIT satellites (and other CCSDS satellites)
The Harbin Institute of Technology satellites LilacSat-2, BY70-1 and the upcoming LilacSat-1 all use a concatenated code with an convolutional code and a (255,223) Reed-Solomon code according to the...
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