239ALFEROV: Image Transmissions

Satellites & Observations Observations
21

Works fine. Need better SNR I suppose. I do the manual tracking. Another option is to use skyroof.

22

i try playing audio ogg from satnogs observations. is possible?

23

Yes that works too. But I have found that at low SNRs the decoding is poor. Try this from the recent recording.

Alfrev SSDV 16th Aug 26.zip (8.5 MB)

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24

im trying decode from this obs. but only result broken jpeg

25

Try the zip I have shared. This is from the pass few minutes ago.

1 Like
26

same result. the jpg output still broken.

wondering..

satsdecoderv0.3.6
satsdecoderv0.3.6943×676 42 KB

soundmodemgeoscan27
soundmodemgeoscan27756×562 40.5 KB

27

Maybe this short video can help you.

Jan | PE0SAT

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28

May be the version issue.

1 Like
29

thank you jan! i follow and still same.

i’m trying also running from source

image
image709×291 13.7 KB

even i run the windows .exe version, running with wine, but still same.

homework :smiley: maybe should run on other computer..

30

Play PE0SAT’s observation again but only the very first packet. This holds the SOI (Start Of Image hex sequence).

And check if STARTER SOI switches to green.

SOI
SOI1020×535 110 KB

1 Like
31

update:
i try change from AGWPE client, to KISS TCP Client on SatDecoder and enable kiss server on soundmodem. now its better, can decode the image. with same observation # 14795307 but still not perfect as @PE0SAT video. @dl7ndr , the SOI is green.

but i’m download first the ogg audio file, than play using ocenaudio. because if i directly play the audio from satno website, the picture is worst.

maybe the problem is from soundmodem self or wine…

i run the soundmodem with this command, with no error or warning on console:
env WINARCH="win32" env WINEPREFIX="$HOME/wine" wine hs_soundmodem.exe

sot
sot982×687 154 KB

1 Like
32

Sounds like SoundModem cannot decode all packets.
Check the volume level on the record tab on pavucontrol for ALSA plug-in [wine].

1 Like
33

239ALFEROV_N6_2026-08-16T16-22-14Z
239ALFEROV_N6_2026-08-16T16-22-14Z640×642 23.2 KB

Lost Few Packets

3 Likes
34

My guess audio routing towards hs_soundmodem.

I used pulseaudio in the past and now pipewire because Debian has switched.

Jan | PE0SAT

2 Likes
35

Do you know if gr-satellites supports the 2.7 version of GEOSCAN?

36

gr-satellites v5.9.0 supports 239Alferov.

1 Like
37

Thanks!
I was not sure because the .yml file just says framing: GEOSCAN for both the old GEOSCAN satellites and for RS61S (239Alferov).
But you are right,

gr_satellites 239Alferov --audio --samp_rate 48e3 --kiss_server 8001

reads also the image data.

@bali, wanna give it a try with that?
Don’t forget to switch to submit_tlm = no in gr_satellites’s config.ini, so nothing will be submitted to SatNOGS.

However, I realized a long time ago that gr_satellites’s decoding is quite poor.

GEOSCAN with grsatellites
GEOSCAN with grsatellites1572×622 155 KB

1 Like
38

hi thank you. yes i had try gr_satellites before, but with --kiss_out option, then input the kiss file into satdecoders.

39

i use pavucontrol

40

Yes it does, you can set the frame size value.

Below two examples:

name: GEOSCAN-EDELVEIS
alternative_names:
   - RS20S
   - GEOSCAN
norad: 53385
data:
   &tlm Telemetry:
     unknown
transmitters:
   9k6 FSK downlink:
     frequency: 436.200e+6
     modulation: FSK
     baudrate: 9600
     framing: GEOSCAN
     frame size: 66
     data:
     - *tlm

name: 239ALFEROV
alternative_names:
  - RS61S
norad: 64881
data:
   &tlm Telemetry:
     unknown
transmitters:
   9k6 FSK downlink:
     frequency: 436.270e+6
     modulation: FSK
     baudrate: 9600
     framing: GEOSCAN
     deviation: 4800
     frame size: 74
     data:
     - *tlm

Jan | PE0SAT

3 Likes