[amsat-bb] Chinese Lunar sats

[Edson W. R. Pereira]

Jean Marc,

I've used a home-made 4-el LFA tuned for 436.5 MHz. It is the one in
Figure-3 in this article:

http://amsat-br.org/cubesat-serpens-decodificacao-dos-sinais/

The preamp used was an ARR SP432VDG (not the one shown in the picture). The
RX hardware was a Nooelec NESDR Smart (RTL-SDR).

73, Edson PY2SDR


On Wed, May 23, 2018 at 3:31 PM, Jean Marc Momple <
jean.marc.momple at gmail.com> wrote:

> 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 <ewpereira at gmail.com>
> 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 <
> jean.marc.momple at gmail.com> 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 <hamsat at xs4all.nl> 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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>> _______________________________________________
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>
>
>