You could tune into the digital signals with a bit of SDR
<https://en.wikipedia.org/wiki/Software-defined_radio> software and a bit
of kit. Although the signals are digitally encoded. Like trying to listen
to a broadcasted MP3 stream you need an MP3 encoder. So you would need the
digital encoder software. Which will probably be property of course. I
seen bits of kit for running your own GSM cellular network.

850/900MHz will mostly be used for GSM while 1800MHz will be used for data
mostly like 3G.

On 8 November 2014 05:21, Julian Smith <julian.smith@???> wrote:

> Semi relivant:
>
> http://berlin.ccc.de/~tobias/25c3-locating-mobile-phones.pdf
>
> _______________________________________________
> unSYSTEM mailing list: http://unsystem.net
> https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/unsystem
>
>