My ten cent ADS-B antenna replaces the RTL-SDR stock antenna. Amazingly, it doubles my coverage of aircraft flying around Calgary.
I thought I would do some cheap experiments to see if I could improve on my initial ADS-B tracking system. I built this experimental ground plane antenna using a Pepsi can. No, it does not have to be a Pepsi can. That is simply my beverage of choice. A Coke or beer can would work just as well, as long as it is made of aluminum.
By making an antenna tuned to 1090 MHz, I obtained three coverage improvements. All of these result from increased signal reception.
- Better coverage of take off and landing. With the old antenna, I lost aircraft signals around 1500 feet above ground when the planes were landing. With the new antenna, I get coverage down to ground level.
- Better medium altitude coverage. The new antenna fills in gaps and provides solid coverage out to 40 nautical miles.
- Better high altitude coverage. This almost doubled. To the north, which is the clearest direction, I can see high altitude flights almost all the way to Edmonton. To the east, Saskatchewan.
The dark circles on the map are at 40, 80 and 120 nautical mile radius.
Putting Together the Ten Cent ADS-B Antenna
I call this the ten cent ADS-B antenna because that is the deposit I gave up by not recycling the Pepsi can. Every thing else was in my junk box. Aside from the can, the parts are an F-type bulkhead connector, a small piece of wire and an RG-6 coaxial cable.
Just to be clear, I take no credit for invention. You can find detailed DIY instructions on ADS-B Exchange. But there is really no magic here. Any radio person knows how to design and build a ground plane antenna. In this case, we use the aluminum can as the ground plane. The short piece of wire fits into the center for the F-type connector. The F-type bulkhead connector gets tightened down through a hole in the bottom of the Pepsi can. Be careful when you cut the can, though: the edges are sharp.
If you cut the aluminum can and short wire to around 70 millimeters, you end up with a properly designed ground plane antenna for 1090 MHz. Its impedance is probably around 50 ohms. This is a slight mismatch for the 75 ohm receiving system, but close enough.