Tracking Request of JINJUSat-1

Hello, My name is Hongju So, a member of JINJUSat-1 team.

I’d like to request you to tracking and observing the JINJUSat-1’s signal.

The JINJUSat-1 will be launched 23.11.11 18:49 UTC and deployed 23.11.11 19:48 UTC. (Expected)

JINJUSat-1’s transmitter spec is as follows :

  • Frequency : UHF 435.185 MHz
  • Protocol : AX.25
  • Modulation : BPSK-G3RUH
  • Data rate : 9600bps
  • Beacon interval : 10s

Beacon example and included information is in the following attachment.

JINJUSat-1 Beacon TM Information.pdf (288.8 KB)

You can use the UZ7HO’s soundmodem(version : G3RUH-BPSK-9k6) to decode JINJUSat-1’s signal.

Thanks for your help.


Welcome Hongju So,

Thanks for sharing this information.
I have question, is there somewhere a audio recording that can be used to test some demodulaters and maybe also decoders.

I for example would like to test the following gr_satellites yml definition.

name: JINJUSAT-1
norad: 99026
  &tlm Telemetry:
    telemetry: ax25
  9k6 BPSK downlink:
    frequency: 435.185e+6
    modulation: BPSK
    baudrate: 9600
    framing: AX.25 G3RUH
    - *tlm

All the best with the coming launch.



Hello Jan PE0SAT,

I share you the google drive link, included JINJUSat-1’s beacon signal file.
JINJUSat-1 Beacon - Google Drive

You can play it through SDR#.

I really appreciate your help.

Hongju So


Thanks for sharing the files.

I am unable to replay the files as IQ baseband and use them as input.

The output has a drop at the center and some agc behaviour.


those recordings look pretty odd, first one has agc that messes quite a bit with the packets. it also looks like it has signal mirrored on both sides of DC.
how were these made ?
for replay by other tools just plain IQ is preferred (decimated, centered), not any ssb or fm demodulation, nor agc.
there might be better tips, these just some off the cuffs suggestions.

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Hello SA2KNG,

I change record method from audio recorder to baseband recorder in SDR#.

You can download new recorded files link below:

Thank you for your advice.

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Hello, everyone.

I share you updated TLE from Space X.

JINJUSat-1_Deployed Generated TLE.txt (140 Bytes)

Thanks for your help.


Allright, I see it’s a float32 wav at 192kHz and my SDR# is not working at the moment, neither is SDR++ with these floaty wavs. In Audacity I can see there’s a very strong signal at least.

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