All posts by by314

RTL-SDR Meets Radio-SkyPipe and RS Spectrograph

Eureka… sort of.

I have written an application that allows you to use inexpensive RTL dongle radios to feed my strip chart program, Radio-SkyPipe (RSP), and my Radio-Sky Spectrograph (RSS), with wideband data.  The program is called RTL Bridge.  I have never claimed to be an imaginative program namer. It works like this:

I consider this experimental as of now, and invite others to test RTL Bridge with RSS and RSP.  If you think you want to try it read the help file here. You will need to install RSS if you have not done so and if you already have it installed, you will need the new update.  It is all in that help file. RSS is free by the way.  This could be the start of a nice hydrogen line study for very little money.


Triangulation of a VHF signal with RTL-SDR !!!

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.

Equipment used:

  • RTL-SDR TV dongle (
  • GPS receiver (NMEA or GPSd compatible)
  • 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