Hi Ross, My initial GSM tests were done in the 70 cm band with low power (0.5 W). I recorded them here: https://www.youtube.com/watch?v=LC3GH0vp-iQ
After that, as suggested by some local amateurs who are also part of the regulations comittees here, I moved it in the 1.2 GHz band with increased power. The frequency split in both cases being 5 Mhz. As a client, I use a modified version of gr-gsm which supports transmission (through the USRP SDR hardware). Osmo-trx will also somewhat work but needs some patches to make it compatible as a GSM client. You can read more about this subject on the OsmocomBB mailing list. So yes, I am using a SDR frontend as a client. Some people have figured out how to hack some old mobile phones to allow scanning and camping out of band. Myself, I spent some time trying to reverse-engineer Qualcomm hardware but gave up as too expensive in man-hours. Other YO hams are running LTE on the 2.3 GHz band also using open source software and Chinese phones which have this LTE band. I'm not that interested in LTE though because it requires a lot of computing power and running a base station on a small Linux board is not possible. The way I see it, SDR hardware will continue to get smaller and cheaper, maybe even hit a price point of $50. Might as well get adjusted to that. 73, Adrian YO8RZZ On 11/11/17, Ross Whenmouth <r...@topwire.co.nz> wrote: > Hi Adrian, > > I suspect that many of the people here use proprietary SDR hardware - if > code is linked with an appropriate HAL (hardware abstraction layer) eg > libosmosdr/GNUradio, then it is pretty easy to swap the USRP for a > BladeRF, or LimeSDR, or any other SDR with suitable capabilities which > is supported by the HAL... > > Have you been using SDR for user GSM stations as well? or mobile phones > with custom configuration/special SIM card/hacked firmware? > Operating on 33cm or on a different band? (23 or 13 cm?) > Using the "standard" 45 MHz duplex split, or something different? (the > 33cm amateur allocation here in New Zealand is not wide enough to > accommodate a 45 MHz split) > > > 73 de ZL2WRW > Ross Whenmouth > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Freetel-codec2 mailing list > Freetel-codec2@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
