If you are not familiar with Software Defined Radios (SDR), you should google it and get up to date because it is the coolest thing ever. With a super cheap USB Stick used as TV tuner and using a special drivers, you can convert your PC into a radio receiver covering from 60 MHz up to 1800 MHz. I have been able to get the position of several air planes close to me, by using an usb television receiver ( RTL ) used as Software Defined Radio, my Airband Wire Dipole tuned for 118 MHz and a couple of free windows programs to decode the data, How cool is that!!!!
I have follow a few tutorials on-line to be able to decode the ADS-B signal sent by airplanes to report their position to earth stations. There is a webpage that keeps tracks of the airplane positions over the world, the webpage is http://www.flightradar24.com. You will be able to get the same information using the SDR RTL and a couple programs. The following picture shows the data that I was able to obtain, just with a simple antenna not meant to receive in the 1090MHz band. I guess if I used a better antenna, I could obtain data from further planes, but it was enough to me to see that it is working.
Configuration Steps that I followed:
I used several tutorials online to configure everything, I think this tutorial explain it very well LINK, but if you want to see how I did it, keep reading !! . You will need the following software, please download first the programs and install it before continuing to the next steps.
- A working SDR USB stick working with the right drivers ( google for information )
- SDR Sharp (SDR#) – Link
- ADSBScope – Link
1. Configure the RTL USB dongle: Ofset and Gain
The first thing that I did was try to detect in the waterfall spectrum window of my SDR Software around the ADS-B frequency of 1090 MHz, to see first if my antenna suitable to receive the signal and also to adjust the frequency offset and gain of the RTL. To do that I will recommend first, to open http://www.flightradar24.com, and wait until a plane is close to your location, this will help to increase the power signal in your SDR Software. Once you start to see the small burst of data, try to calibrate the frequency using the ppm ofset until the spectrum is center in 1090 MHz, also play with the Gain and get the number for the best Signal to Noise ratio.
2. Start the ADB-S server: Monitoring the planes
Inside the installation folder of the SDR# there is the ADSBSharp software used to tune the SDR USB into the ADB-S frequency, decode the signals and give the data as a server. The following picture shows my current configuration. Note that if everything is working good, you should see the Frames/sec value vary depending of how much data you are getting, If you dont get anything, review your configuration. After this we have to configure the program to display the received data.
First we need to configure the ADSB Server parameters, go to ” other > Network > Network Setup“.
The following window will be shown and you need to click in “ADSB#” and the “Local” button to configure the server address. If you didn’t touch the ADSB Server parameters, this should be straight forward.
Obtain the map of your area, go to ” load Maps > …” , for me it was the north of Europe.
Click in the following button to start to obtain the data. If everything is working good, you should start to see airplane data. You may use the Zoom cursors to locate your actual position in the map.
This is the Dipole antenna that I used. I used a welding rood of 2.4mm of diameter, with a lenght of 1m on each side of the dipole. It works!!