Re: [amsat-bb] Chinese Lunar sats

23 May 2018

      Edson,
My congratulations (and for sure from the the community) for achieving the reception of the Longjiang and decoding the telemetry.
I would be grateful if you could let me know what antenna you have been using so far (up to 64K km) just for my learning.
73
Jean Marc (3B8DU)
...
On May 22, 2018, at 8:38 PM, Edson W. R. Pereira [email protected] wrote:
Jean,
I suggest usign the live Ubuntu ISO image with gnuradio and the necessary OOT modules for monitoring the GMSK signals. While installing gnuradio and the OOT modules manually can be done, it takes some effort. Running the live image is much easier. You do need a fast computer with at least four CPU cores  to be able to run all the flowgraphs.
I had some difficulties with the doppler correction in my setup during the first pass. The predictions seemed off and I had to manually adjust the frequency offset to get the signals into the demodulators' passbands. Once that was done, I could decode the GMSK telemetry from both satellites up to 64000 km. Above 64000 km, my small antenna was no longer enough. I will get a better antenna ready and will try monitoring again over the weekend.
73, Edson PY2SDR
On Tue, May 22, 2018 at 1:21 PM, Jean Marc Momple <[email protected] mailto:[email protected]> wrote:
Nico,
I have been trying to capture the signals from the both Longjiang sats for the past 2 days.
On Monday it seems that I receive a carrier on the right frequency but was not able to confirm that it was from Longjiang 1.
I used the initial Keppler’s and now using Celestrac in SatPC32 which seems to be OK when comparing with N2YO ele/az. I have been monitoring on the announced FX and having also JT4G “on” for about this evening without any results.
For sure I am doing something wrong but cannot figure it out due to the lack of information.
Also, trying to get a decoder software for the GMSK telemetry is quite difficult for a non-IT geek, I don’t have clue how to have the published GITHUB decoder to work on my Windows computers…
Here we are this side.
Quite frustrating that the communication is not that good, as if the project team want the maximum of feedback and TLM they should provide a minimum of info. Just a personal opinion.
Anyway will try hard to receive these birds as a real opportunity for HAM to learn more on outer space com, if anyone can help and share, particularly the guys who already decoded the birds, it would be more welcomed.
73
Jean Marc (3B8DU)
...
On May 22, 2018, at 5:03 PM, Nico Janssen <[email protected] mailto:[email protected]> wrote:
After their launch on 2018-05-20 at 21:28 UTC, LJ 1 and LJ 2 were
maneuvered onto a track to the Moon. Several amateurs received
telemetry from the satellites. But now LJ 1 appears to encounter
problems.
Quoting Wei BG2BHC:
"Can you help to find amateurs in the US to help to monitor DSLWP-A
on 435.425 and 436.425 now?
We lost the contact of satellite A on S band after an orbit adjustment.
We just tried to switch on UHF, but we don't know if it works or not.
The sat is just above South America.
If it works, 435.425 should be 500bps GMSK and JT4 alternately.
436.425 should be 250 bps GMSK.  Bothtransmit once in 5 minutes.
Thank you very much!
Wei"
73,
Nico PA0DLO
On 22-05-18 12:15, Mike Seguin wrote:
...
Any word on the two Chinese microsats LongJiang 1 & 2?

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