From 246tnt at gmail.com Tue May 25 17:26:46 2021 From: 246tnt at gmail.com (Sylvain Munaut) Date: Tue, 25 May 2021 19:26:46 +0200 Subject: RACH scan In-Reply-To: References: Message-ID: Hi, > I have made some captures on the L-band uplink channels and tried to decode the RACH messages. All four consecutive TCH channels (according to the spot beam) were recorded and a call was made during the recording. > > I am using the GRC block gmr_rach_scan.grc. I have removed the IQ swap from the graph, as suggested in the mailing list. The sampling rate and samples-per-symbol values have been set to 93.6k and 4, respectively. Oops, looks like I complete missed this ... sorry. That graph was made to scan large bandwidth capture for RACH ... It's very probable that a bunch of constants and thresholds value are just not appropriate for a narrow band capture. It kind of always required tweaking depending on the case. Basically manually finding a RACH (in frequency and time), then look at all the intermediate steps of the graphs (and possibly inside the block) to see if it detects that particular one and tweak it until it does. And then you can run it to find the other ones. I don't have any setup any more to capture C-band uplink so I have not run that graph in years .... but that's all I remember about it. Cheers, Sylvain From 246tnt at gmail.com Tue May 25 17:29:58 2021 From: 246tnt at gmail.com (Sylvain Munaut) Date: Tue, 25 May 2021 19:29:58 +0200 Subject: Few questions about Osmo-GMR In-Reply-To: <910e0987d07867eb1954ab26ae63ab80@optisprint.net> References: <910e0987d07867eb1954ab26ae63ab80@optisprint.net> Message-ID: Hi, > 1. I need some more info about S band GMR - what sat is this , az / el , > what trafic etc. No clue. Hasn't been observed ... by me at least. > 2. About gmr1 ambe decode - i tried about dozens of .dat files from gmr1 > rx live , some give me ! codec errors , some not , but all .wav audio > files are scrambled ,speesh is not recognized at all .. is there some > clear traffic at all, or all is A5/2 coded ? On thuraya it's all encrypted AFAIK so you won't get anything if you don't have the key. > 3. If all is scrambled where i may find offline tables / H n matrix/,any > source that may generate them ? And if i have tables how they will be > integrated with existing osmo-gmr ? I see gmr1_gen_mat that generates > G/g matrix .. some more info about that .. .G and .g files seems so > small .. The G / g matrix are small, nothing big to them. And no, I don't have any plan for integration of any crypto break inside the open-source osmo-gmr itself. If you have commercial need for it, you can contact me privately. Cheers, Sylvain From kmsun at hanmirtech.co.kr Wed May 26 01:26:58 2021 From: kmsun at hanmirtech.co.kr (=?UTF-8?B?7ISg6rK966+4?=) Date: Wed, 26 May 2021 10:26:58 +0900 Subject: osmo-live error Message-ID: An HTML attachment was scrubbed... URL: From 246tnt at gmail.com Wed May 26 05:44:46 2021 From: 246tnt at gmail.com (Sylvain Munaut) Date: Wed, 26 May 2021 07:44:46 +0200 Subject: osmo-live error In-Reply-To: References: Message-ID: Hi, I executed like below >> >> ./gmr1_rx_live 4 267:tnt-call-267-93600.cfile 268:tnt-call-268-93600.cfile >> >> >> But I couldn't find message (Authentication Request, Ciphering Mode Command etc) >> >> because sync id and priv->sync_id are different. >> >> >> So, I ignored sync id but I couldn't reproduce the pcap output. >> >> That's expected. The recording contained some private information. In the pcap I was just able to blank out those bytes but in the RF recording, I had to intentionally jam some packets to make them non-decodable and that means you can't really decode that example fully, that's why I provided the pre-decoded pcap for. Cheers, Sylvain -------------- next part -------------- An HTML attachment was scrubbed... URL: