<h3>Entries from September 2017.</h3>
+ <div class="entry">
+ <div class="title">
+ <a href="http://people.skolelinux.org/pere/blog/Visualizing_GSM_radio_chatter_using_gr_gsm_and_Hopglass.html">Visualizing GSM radio chatter using gr-gsm and Hopglass</a>
+ </div>
+ <div class="date">
+ 29th September 2017
+ </div>
+ <div class="body">
+ <p>Every mobile phone announce its existence over radio to the nearby
+mobile cell towers. And this radio chatter is available for anyone
+with a radio receiver capable of receiving them. Details about the
+mobile phones with very good accuracy is of course collected by the
+phone companies, but this is not the topic of this blog post. The
+mobile phone radio chatter make it possible to figure out when a cell
+phone is nearby, as it include the SIM card ID (IMSI). By paying
+attention over time, one can see when a phone arrive and when it leave
+an area. I believe it would be nice to make this information more
+available to the general public, to make more people aware of how
+their phones are announcing their whereabouts to anyone that care to
+listen.</p>
+
+<p>I am very happy to report that we managed to get something
+visualizing this information up and running for
+<a href="http://norwaymakers.org/osf17">Oslo Skaperfestival 2017</a>
+(Oslo Makers Festival) taking place today and tomorrow at Deichmanske
+library. The solution is based on the
+<a href="http://people.skolelinux.org/pere/blog/Easier_recipe_to_observe_the_cell_phones_around_you.html">simple
+recipe for listening to GSM chatter</a> I posted a few days ago, and
+will show up at the stand of <a href="http://sonen.ifi.uio.no/">Åpen
+Sone from the Computer Science department of the University of
+Oslo</a>. The presentation will show the nearby mobile phones (aka
+IMSIs) as dots in a web browser graph, with lines to the dot
+representing mobile base station it is talking to. It was working in
+the lab yesterday, and was moved into place this morning.</p>
+
+<p>We set up a fairly powerful desktop machine using Debian
+Buster/Testing with several (five, I believe) RTL2838 DVB-T receivers
+connected and visualize the visible cell phone towers using an
+<a href="https://github.com/marlow925/hopglass">English version of
+Hopglass</a>. A fairly powerfull machine is needed as the
+grgsm_livemon_headless processes from
+<a href="https://tracker.debian.org/pkg/gr-gsm">gr-gsm</a> converting
+the radio signal to data packages is quite CPU intensive.</p>
+
+<p>The frequencies to listen to, are identified using a slightly
+patched scan-and-livemon (to set the --args values for each receiver),
+and the Hopglass data is generated using the
+<a href="https://github.com/petterreinholdtsen/IMSI-catcher/tree/meshviewer-output">patches
+in my meshviewer-output branch</a>. For some reason we could not get
+more than four SDRs working. There is also a geographical map trying
+to show the location of the base stations, but I believe their
+coordinates are hardcoded to some random location in Germany, I
+believe. The code should be replaced with code to look up location in
+a text file, a sqlite database or one of the online databases
+mentioned in
+<a href="https://github.com/Oros42/IMSI-catcher/issues/14">the github
+issue for the topic</a>.
+
+<p>If this sound interesting, visit the stand at the festival!</p>
+
+ </div>
+ <div class="tags">
+
+
+ Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern</a>, <a href="http://people.skolelinux.org/pere/blog/tags/surveillance">surveillance</a>.
+
+
+ </div>
+ </div>
+ <div class="padding"></div>
+
<div class="entry">
<div class="title">
<a href="http://people.skolelinux.org/pere/blog/Easier_recipe_to_observe_the_cell_phones_around_you.html">Easier recipe to observe the cell phones around you</a>
<p>Note, due to a bug somewhere the scan-and-livemon program (actually
<a href="https://github.com/ptrkrysik/gr-gsm/issues/336">its underlying
-program grgsm_scanner</a>) do not work with the HackRF radio. It do
+program grgsm_scanner</a>) do not work with the HackRF radio. It does
work with RTL 8232 and other similar USB radio receivers you can get
very cheaply
(<a href="https://www.ebay.com/sch/items/?_nkw=rtl+2832">for example
<li><a href="http://people.skolelinux.org/pere/blog/archive/2017/08/">August (1)</a></li>
-<li><a href="http://people.skolelinux.org/pere/blog/archive/2017/09/">September (2)</a></li>
+<li><a href="http://people.skolelinux.org/pere/blog/archive/2017/09/">September (3)</a></li>
</ul></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/chrpath">chrpath (2)</a></li>
- <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (152)</a></li>
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (153)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (158)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/drivstoffpriser">drivstoffpriser (4)</a></li>
- <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (352)</a></li>
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (353)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (23)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (64)</a></li>
- <li><a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern (103)</a></li>
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern (104)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/raid">raid (1)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/stortinget">stortinget (12)</a></li>
- <li><a href="http://people.skolelinux.org/pere/blog/tags/surveillance">surveillance (51)</a></li>
+ <li><a href="http://people.skolelinux.org/pere/blog/tags/surveillance">surveillance (52)</a></li>
<li><a href="http://people.skolelinux.org/pere/blog/tags/sysadmin">sysadmin (3)</a></li>
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