Dear community members, I'm interested in intercepting L band up-link RACH channel I found the BCCH channel of the spot beam I'm currently in then scan the same ARFCN but in uplink I had a cfile and I tried to read it using gr-gmr1 https://github.com/osmocom/osmo-gmr/tree/sylvain/gr/gr-gmr1 in the branch sylvain/gr https://github.com/osmocom/osmo-gmr/tree/sylvain/gr but i have no results , may be I don't know how to use the read utility in sylvain/gr https://github.com/osmocom/osmo-gmr/tree/sylvain/gr I also have another question about the file test.pcap in http://people.osmocom.org/tnt/gmr/ how can I have a file like it and is it l band RACH data or C band.
Hi,
I'm interested in intercepting L band up-link RACH channel I found the BCCH channel of the spot beam I'm currently in then scan the same ARFCN but in uplink I had a cfile and I tried to read it using gr-gmr1 in the branch sylvain/gr but i have no results , may be I don't know how to use the read utility in sylvain/gr
Although the method should work to detect the RACH burst on L-band, it has only ever been tested on C-band wideband captures, so YMMV. Note that the example .grc graph that's provided does an IQ swap because usually when you get samples from a C-band LNB they underwent a spectrum inversion due to the high-side LO mixing inside the LNB. If you're working off a direct capture off L-band you need to remove that swap from the graph.
Also, are you sure you actually _have_ RACH requests in your file and they don't saturate your receiver ? If you have an example capture to post, put it online somewhere and post the link.
I also have another question about the file test.pcap in http://people.osmocom.org/tnt/gmr/ how can I have a file like it and is it l band RACH data or C band.
This was captured on C-band.
Cheers,
Sylvain Munaut
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mohamed yehia -
Sylvain Munaut