Locating the source of a signal
Privacy and security is a big topic in today’s society. With the advances made in technology, the commercial and military techniques of the past is suddenly becoming available for everyone.
With almost everything being wireless today anything and anyone can be tracked.
With this in mind I decided to try and track a signal with easy to buy equiptment.
I started with a cheap TV tuner known as RTL-sdr and the the stock/cheap supplied antenna.
Scanning the VHF band I noticed a strong permanent encrypted signal. Judging from the Norwegian frequency plan this looks to belong to either “Norwegian Directorate for Civil Protection” or the local police that is known to operate in the same area provides an interesting subject for this exercise. The signal strength was higher than commercial FM radio stations in the area suggesting the transmitter would be very close by.
- RTL-SDR TV dongle (http://sdr.osmocom.org/trac/wiki/rtl-sdr)
- GPS receiver (NMEA or GPSd compatible)
- rtlsdr-scanner (http://eartoearoak.com/software/rtlsdr-scanner)
Using the software and data collecting from a 15 min ride in my car I was able to track the source of the digital signal broadcasting with reasonably accuracy. The signal originates from a modern residential area. For security reasons this test is done with a cheap antenna and a low sampling rate. Enough to show the approximate area, but will not show what building.
|Heatmap overlayed on Google Earth|