Listening to the FreeDV net by WebSDR
Since I'm away from my usual QTH, I decided to join yesterday's FreeDV net by listening through the University of Twente WebSDR and giving signal reports on the QSO Finder to the stations transmitting....
View ArticleDecoding LilacSat-2 telemetry
After having my first QSO through the Harbin Institute of Technology amateur radio satellite LilacSat-2, I decided to give a serious try to the telemetry decoding software. This is available as a...
View ArticleTesting microphone performance for Codec 2
Codec 2 is the open source and patent-free voice codec used in FreeDV, a digital voice mode used in amateur radio. Since Codec 2 is designed to be used at very low bitrates (the current version of...
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Decoding packets from GOMX-3: modulation and coding
Recently, Mike DK3WN pointed me to some decoder software for the satellite GOMX-3. This satellite is a 3U cubesat from GomSpace and transmits in the 70cm Amateur band. It has an ADS-B receiver on...
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KISS, HDLC, AX.25 and friends
A while ago, I uploaded my gr-kiss out-of-tree GNUradio module to Github. This is a set of blocks to handle KISS, HDLC and AX.25, which are the protocols used in amateur packet radio. There are several...
View ArticleUsing the CC1101 and Beaglebone black for IP traffic on 70cm
Lately, I have been experimenting with using a CC1101 chip together with a Beaglebone black single board ARM computer to transmit IP traffic over the 70cm Amateur band. There has been a similar project...
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Receiving the Vaisala RS92-SGP radiosonde launched from Madrid-Barajas
Each day, at 01:00UTC and 11:00UTC a Vaisala RS92-SGP radiosonde is launched from Madrid-Barajas airport. This is a small electronics package tied to a helium balloon that ascends up to between 24 and...
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How hard is it to decode 3CAT-2?
In a previous post, I looked at the telemetry packets transmitted by the satellite 3CAT-2. This satellite transmits 9600bps AX.25 BPSK packets in the Amateur 2m band. As far as I know, it is the only...
View ArticleA 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...
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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 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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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...
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...
View ArticleOpen telecommand for BY70-1
Recently, Wei BG2BHC has published instructions for the use of BY70-1's camera by Amateurs. Essentially, there are three commands that can be used: 0x00 to take a picture and send it, 0x55 to take a...
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GNU Radio decoder for AO-73
During the last few days, I have been talking with Edson PY2SDR about using GNU Radio to decode digital telemetry from AO-73 (FUNcube-1) and other FUNcube satellites. I hear that in Virginia Tech...
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