No Decoding

[ik8ozv]

Hello Folks, please I am trying to decode the satellite but I do not get any incoming datas. At the bottom window of the gnuradio I can just read:

correlate_access_code_tag_bb :debug: writing tag at sample 10386 correlate_access_code_tag_bb :debug: writing tag at sample 34649 correlate_access_code_tag_bb :debug: writing tag at sample 4754 correlate_access_code_tag_bb :debug: writing tag at sample 29580 correlate_access_code_tag_bb :debug: writing tag at sample 64486 correlate_access_code_tag_bb :debug: writing tag at sample 122344 correlate_access_code_tag_bb :debug: writing tag at sample 69761 correlate_access_code_tag_bb :debug: writing tag at sample 17948

Please where am I still missing? Any Help? Thanks Enzo

[daniestevez]

Hello Enzo, can you give more information about what you're doing? If you tell us exactly how you're running gr-satellites and share a recording we will be able to replicate your problem.

[ik8ozv]

Thanks Dani, for coming back, As i have lost all my datas due to an HD failure i am trying to put on again all. I have installed all but when i run a grc flowgraps i got the issue. Please what do you need to know that ìt can help you to understand where am i missing?

Dani i do not know if can help but when i run a grc file i can read in the bottom window:

Generating: '/media/enzo/ESD-ISO/IRIS_A.py'

Executing: /usr/bin/python3 -u /media/enzo/ESD-ISO/IRIS_A.py

QSocketNotifier: Can only be used with threads started with QThread Funcube Pro+ :info: Start init fcdpp Funcube Pro+ :info: Funcube Dongle Pro+ found as: hw:1,0 fcdpp_control :info: FunCube Dongle V2.0 initialized. fcdpp_control :info: Dongle: FCDAPP 20.03 fcdpp_control :info: LNA gain enabled fcdpp_control :info: Mixer gain enabled fcdpp_control :info: IF gain set to: 1 fcdpp_control :info: Set Frequency to: 437405000 Hz [doppler] Waiting for connection on: 127.0.0.1:4532

Thanks

[ik8ozv]

@daniestevez Dani please any news for me? Thanks Enzo

[daniestevez]

With the information you have given it is really difficult to help you.

Please indicate what you are doing with as much detail as possible, including, but not limited to: what version of gr-satellites you are running, what is your operating system, where did you get that IRIS_A.py (since such a file is not distributed with gr-satellites anymore). Also, since the problem could be with your SDR receiver, make a recording, try to decode from the recording, and share the recording.

[ik8ozv]

Dani, i have finally solved the problem with the FCDPP but now i am looking for some flowgraphs to decode the satellite with the FCDPP. Please can you help me? I ma using Ubuntu 22.04.02 with gnuradio 3.10.1.1. I have tried to open the ones in gr-satellites/examples/satellites and other but i get them with red blocks and also i do not see the FCDPP as source. Maybe before i lost all something has changed. Please can you point me to the correct way? Thanks in advance

73's de Enzo IK8OZV

[daniestevez]

The easiest way to set this up is probably to use an external application such as GQRX to control the FCDPP, tune to the signal of interest and stream audio data by UDP, and then use the gr_satellites command line tool to receive the UDP data and perform decoding. The documentation for the command line tool can be helpful.

[ik8ozv]

Dani, right now i had a pass of Gomx-1 and following your suggestion i have ran in the terminal the comand:

gr_satellites gomx-1 --udp --samp_rate 48e3

using the GQRX port 7355 and have noticed that when I got a packet I got in the terminal:

correlate_access_code_tag_bb :debug: writing tag at sample 32762 correlate_access_code_tag_bb :debug: writing tag at sample 36978 correlate_access_code_tag_bb :debug: writing tag at sample 118515

Please any suggestions? Thanks

[daniestevez]

Maybe the only problem is that the signal quality is not good enough. I suggest you try doing an IQ recording first, and then work with that IQ recording, and share the recording, so that others can try to replicate what you're doing.

[ik8ozv]

Dani Followed your suggestion. Thanks. This is what i have done on an IRIS-A pass. I ran in the terminal the comand:

gr_satellites IRIS-A --udp --samp_rate 48e3

and i got as response:

udp_source :info: Listening for data on UDP port 7355.

I have opened GQRX and enabled the UDP button after been sure that the network port was set as 7355. After a couple of burst i did not get anything on the terminal so i have , as you suggested me, enabled the REC button and continued the pass. After the pass i have loaded in gnuradio the SATELLITE_DECODER.grc from the folder:

/gr-satellites/examples/satellite_decoder

I have the chenged the Satellite Decoder block changing the Satellite name to IRIS-A and the Wav file source block pointing o the recorded file. Ran it but did nit see anythin so i have tiefe to switch from NO to YES the Repeat field in the Wav File Source block. Ran again and this time after a couple of seconds got:

message_debug :info: The print_pdu port is deprecated and will be removed; forwarding to print. * VERBOSE PDU DEBUG PRINT ** ((transmitter . 9k6 FSK downlink)) pdu length = 30 bytes pdu vector contents = 0000: df b6 f7 1f 67 0c 5d 03 1f 80 62 89 5c 33 1d 05 0010: 96 b6 29 84 e3 30 3d fb bf a0 19 f2 4c e0

---

message_debug :info: The print_pdu port is deprecated and will be removed; forwarding to print. * VERBOSE PDU DEBUG PRINT ** ((transmitter . 9k6 FSK downlink)) pdu length = 32 bytes pdu vector contents = 0000: 00 23 6d cd 4a b7 9c 9e 13 12 8e 1a b8 75 94 67 0010: a3 f6 2f 68 89 49 11 2d 79 77 6f b9 33 66 a4 d8

---

message_debug :info: The print_pdu port is deprecated and will be removed; forwarding to print. * VERBOSE PDU DEBUG PRINT ** ((transmitter . 9k6 FSK downlink)) pdu length = 16 bytes pdu vector contents = 0000: a0 46 65 f5 3c c6 6c 9e b7 16 25 d5 ca b6 50 ad

---

Please why i do not get anything when i run in the terminal:

gr_satellites IRIS-A --udp --samp_rate 48e3

Thanks. P.S.I have attached th recorded file if you want to see.. Thanks a lot Enzo

gqrx_20230723_103610_436920600.zip

[daniestevez]

From a quick look at gqrx_20230723_103610_436920600.zip, the frequency tuning seems to be off by a lot (since there is a large DC offset in the FM demodulated signal), and the file is clipped (probably because the output gain in GQRX is set too high).

[ik8ozv]

Now i am receiving the Greencube and made the same steps and get:

correlate_access_code_tag_bb :debug: Access code: 930b51de correlate_access_code_tag_bb :debug: Mask: ffffffff correlate_access_code_tag_bb :debug: Access code: 930b51de correlate_access_code_tag_bb :debug: Mask: ffffffff correlate_access_code_tag_bb :debug: Access code: 930b51de correlate_access_code_tag_bb :debug: Mask: ffffffff correlate_access_code_tag_bb :debug: Access code: 930b51de correlate_access_code_tag_bb :debug: Mask: ffffffff correlate_access_code_tag_bb :debug: Access code: 930b51de correlate_access_code_tag_bb :debug: Mask: ffffffff correlate_access_code_tag_bb :debug: Access code: 930b51de correlate_access_code_tag_bb :debug: Mask: ffffffff correlate_access_code_tag_bb :debug: writing tag at sample 109470 correlate_access_code_tag_bb :debug: writing tag at sample 218211 correlate_access_code_tag_bb :debug: writing tag at sample 785998 correlate_access_code_tag_bb :debug: writing tag at sample 914208 correlate_access_code_tag_bb :debug: writing tag at sample 915488 correlate_access_code_tag_bb :debug: writing tag at sample 983684 correlate_access_code_tag_bb :debug: writing tag at sample 1185213 correlate_access_code_tag_bb :debug: writing tag at sample 1252364 correlate_access_code_tag_bb :debug: writing tag at sample 722240 correlate_access_code_tag_bb :debug: writing tag at sample 789445 correlate_access_code_tag_bb :debug: writing tag at sample 1856809 correlate_access_code_tag_bb :debug: writing tag at sample 957458

Thanks

[ik8ozv]

Hello Dani, Please any news? I am still struggling to understand how the demodulate and decode the satellites in real time. Any help?

Attached is another record file of the UVSQ_SAT satellite Thanks in advance 73’s de Enzo IK8OZV gqrx_20230729_090435_437013600.zip

[daniestevez]

gqrx_20230729_090435_437013600.zip

This wav file is badly clipped and I can't see any satellite signal in it. I'm going to close this issue now, since the recordings you shared don't have a good signal, so the problem seems to be with your data capturing and not with gr_satellites (and also the issue has been inactive for several months).