| 10 Jan 2024 |
 yasiu | We got another part of the recording down, it's about 60% downlinked | 13:40:13 |
| yasiu | DD7MK - congrats! | 13:40:43 |
| yasiu | You made it on the recording! | 13:41:10 |
| yasiu | Download SDRSharp_20240110_181152Z_0Hz_AF.wav | 18:13:43 |
| yasiu | More data downlinked! Here is SSTV signal. Quite noisy, but it comes through at times | 18:14:36 |
| yasiu | In the morning I should have the entire thing, I'll share the raw IQ samples | 18:15:12 |
 arbitrary | That's really cool. Seems like the SDR works pretty well | 18:28:16 |
 fredy | yasiu: I don't remember the exact frequency, I think it was at 433.565 where I transmitted some voice with my handheld radio. Without not directional antenna I don't expect too much but let me know if you spot anything. :) | 19:37:50 |
| fredy | * yasiu: I don't remember the exact frequency, I think it was at 433.565 where I transmitted some voice with my handheld radio. Without directional antenna I don't expect too much but let me know if you spot anything. :) | 19:38:01 |
| 11 Jan 2024 |
| yasiu | Full recording from OPS-SAT captured during 37c3: https://we.tl/t-qO6eOmZ42r | 10:50:15 |
| yasiu | There are a lot of transmissions apart from our | 10:50:26 |
| yasiu | and we are not the only ones talking in FM :) | 10:50:35 |
| yasiu | It is a binary file of 16bit IQ samples (I + Q 16bit short) | 11:02:53 |
 builderhummel | In reply to @yasiu:0x3c.pl
Full recording from OPS-SAT captured during 37c3: https://we.tl/t-qO6eOmZ42r For using gqrx:
I tried to open it with the device string (file obviously not that ;)) "file=/path/to/your/file,rate=1500000,freq=433550000,gain=60", but I am getting an error stating "rate missing in arguments. please select another device". Anyone here with the same issue?
| 12:55:37 |
| arbitrary | Yeah I think gqrx expects its samples as float32 but the file is int16. I'll poke gnuradio to hack quick converter. | 17:41:07 |
 oldbug | Hm, maybe sox can do that!? | 17:58:48 |
| arbitrary | Pretty sure, but I'm faster at cobbeling together a flowgraph than figuring out how sox works for the 100th time. 🤷 | 18:00:24 |
| arbitrary | This way I also get the sanity check for free | 18:02:11 |
| arbitrary | 
Download 2024-01-11-190125_1894x1096_scrot.png | 18:02:17 |
| arbitrary | Next step is adding a PLL to track one of those carriers and get rid of the doppler shift. | 18:03:02 |
| arbitrary | 
Download 2024-01-11-190547_1490x1075_scrot.png | 18:06:11 |
| arbitrary | Looks about right to me. Eventhough it still has doppler, you can already listen to stuff using gqrx. | 18:06:58 |
| arbitrary | https://files.zenerdio.de/37C3/ builderhummel try the .iq file like this: file=<your path>/OPS-SAT_SDR_exp202_sidloc_binary_1703876618_rate750000_float32.iq,rate=750000,freq=433550000 | 18:12:07 |
| arbitrary | * https://files.zenerdio.de/37C3/ builderhummel try the .iq file like this: file=<your path>/OPS-SAT_SDR_exp202_sidloc_binary_1703876618_rate750000_float32.iq,rate=750000,freq=433550000 | 18:12:28 |
| arbitrary | There is no also https://files.zenerdio.de/37C3/OPS-SAT_SDR_exp202_sidloc_binary_1703876618_rate750000_float32_dedoppler.iq where I used the SP4?? transmission as reference to correct for the doppler shift. Much easier to listen to in gqrx | 19:08:11 |
| builderhummel | In reply to @arbitrary:matrix.org
https://files.zenerdio.de/37C3/ builderhummel try the .iq file like this: file=<your path>/OPS-SAT_SDR_exp202_sidloc_binary_1703876618_rate750000_float32.iq,rate=750000,freq=433550000 I'll try tomorrow, tks | 21:23:06 |
| 12 Jan 2024 |
| yasiu | In reply to @arbitrary:matrix.org
There is no also https://files.zenerdio.de/37C3/OPS-SAT_SDR_exp202_sidloc_binary_1703876618_rate750000_float32_dedoppler.iq where I used the SP4?? transmission as reference to correct for the doppler shift. Much easier to listen to in gqrx Did you correct it for the doppler at our transmission frequency? | 11:38:12 |
| yasiu | Do mind that all the different signals probably have different amounts of doppler shift, because they come from different locations. I've also noticed that some transmissions overlap | 11:39:00 |
| arbitrary | In reply to @yasiu:0x3c.pl
Did you correct it for the doppler at our transmission frequency? Yeah it's the most basic ugly hack: Used a PLL to lock onto your carrier, swapped I and Q on the resulting sinewavey mess (technical Term), multiplied the incomming stuff with that and frequency shiftet everything back so the center frequency is at the center again. Probably messes up some signals at the extrem end of the spectrum. Work well enough that I can listen to a lot of the signals without having to tune. | 17:02:21 |
| 14 Jan 2024 |
|  @carsten:hadeschat.goip.de left the room. | 08:02:15 |
