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Monitoring IMD levels in the EAPSK63 contest
This weekend I have recorded the full EAPSK63 Spanish PSK63 contest in the 40m band with the goal of playing back the recording later and reporting the stations showing excessively high IMD levels. In...
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Waterfalls from the EAPSK63 contest
Last weekend, I recorded the full EAPSK63 contest in the 40m band with the goal of monitoring IMD levels. I made a 48kHz IQ recording spanning the full 24 contest hours (from 16:00 UTC on Saturday to...
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LilacSat-1 downlink usage
In my previous post, I examined a recording of LilacSat-1 transmitting an image. I did some calculations regarding the time it would take to transmit that image and the time that it actually took to...
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A first look at DSLWP SSDV downlink
The Chang'e 4 is a Chinese lunar mission that will land a rover on the far side of the Moon by the end of 2018. To support this mission, the Chang'e 4 relay satellite will be launched six months before...
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WSJT-X and linear satellites: part I
Several weeks ago, in an AMSAT EA informal meeting, Eduardo EA3GHS wondered about the possibility of using WSJT-X modes through linear transponder satellites in low Earth orbit. Of course, computer...
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Acquisition and wipeoff for JT9A
Lately, I have been playing around with the concept of doing acquisition and wipeoff of JT9A signals, using a locally generated replica when the transmitted message is known. These are concepts and...
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WSJT-X and linear satellites: part II
This is a follow-up to the part I post about using WSJT-X modes through a linear transponder on a LEO satellite. In part I, we considered the tolerance of several WSJT-X modes to the residual Doppler...
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P25 vocoder FEC
Following a discussion with Carlos Cabezas EB4FBZ over on the Spanish telegram group Radiofrikis about using Codec2 with DMR, I set out to study the error correction used in DMR, since it quickly...
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JT4G detection algorithm for DSLWP-B
Now that DSLWP-B has already been for 17 days in lunar orbit, there have been several tests of the 70cm Amateur Radio payload, using 250bps GMSK with an r=1/2 turbo code. Several stations have received...
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DSLWP-B first JT4G test
Yesterday, between 9:00 and 11:00, DSLWP-B made its first JT4G 70cm transmissions from lunar orbit. Several stations such as Cees Bassa and the rest of the PI9CAM team at Dwingeloo, the Netherlands,...
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DSLWP-B GMSK detector
Following the success of my JT4G detector, which I used to detect very weak signals from DSWLP-B and was also tested by other people, I have made a similar detector for the 250baud GMSK telemetry...
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Trying to decode EQUiSat
EQUiSat is a cubesat from Brown University that was launched to the ISS on May 21 with the Cygnus CRS-9 supply ship. It was released from the ISS on July 13. The payload of EQUiSat is rather...
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First SSDV transmission from DSLWP-B
As some of you may know, DSLWP-B, the Chinese lunar-orbiting Amateur satellite carries a camera which is able to take pictures of the Moon and stars. The pictures can be downlinked through the 70cm...
View ArticleDSLWP-B corrupted SSDV frames
In my previous post I looked at the first SSDV transmission made by DSLWP-B from lunar orbit. There I used the recording made at the Dwingeloo radiotelescope and showed how to decode the SSDV frames...
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Decoding TANUSHA-3
On August 15, during a Russian EVA on the ISS, a total of four Russian nanosatellites were deployed by hand. Although different online sources give incomplete and contradictory information about which...
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Playing with LilacSat-1
Even though the cubesat LilacSat-1 was launched more than a year ago, I haven’t played with it much, since I’ve been busy with many other things. I tested it briefly after it was launched, using its...
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Decoding Astrocast 0.1
Astrocast 0.1 is an Amateur satellite built by the Lucerne University of Applied Sciences and Arts (Hochschule Luzern). It is an in-orbit demonstrator for a future constellation of small satellites...
View ArticleDecoding 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)...
View ArticleNew decoders for Astrocast 0.1
A couple months ago, I added a decoder for Astrocast 0.1 to gr-satellites. I spoke about the rather non-standard FX.25 protocol it used. Since then, Mike Rupprecht DK3WN and I have been in contact...
View ArticleD-STAR One Mobitex protocol decoded
D-STAR One are a series of Amateur satellites with an on-board D-STAR digital voice repeater. The first satellite of the series, called D-STAR One, was launched on November 2017 but was lost due to a...
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