About 3 years ago I built a PiAware ADS-B receiver with a Raspberry Pi 3B+ computer and a FlightAware Pro Stick Plus ADS-B USB Receiver with Built-in Filter. For the antenna, I used an inexpensive 1090-MHz indoor antenna mounted in the windowsill. This is a very easy, inexpensive, and fun radio project with a Raspberry Pi, and I would encourage anyone interested in radio and/or aviation to build one. The FlightAware website includes parts lists and detailed instructions for building an ADS-B receiver with a Raspberry Pi computer. You can also build an ADS-B receiver with a Raspberry Pi computer and hardware from AirNav.
Automatic dependent surveillance–broadcast (ADS–B) is a surveillance technology in which an aircraft determines its position via satellite navigation and periodically broadcasts it, enabling it to be tracked.
This setup worked fairly well, and I was able to receive position and heading information for several aircraft within a range of approximately 50 nautical miles, and sometimes a bit farther depending upon the altitude of the aircraft. An indoor antenna is a compromise solution and will generally limit the range from which ADS-B signals can be received.
This morning I replaced the indoor antenna with a FlightAware 1090 MHz ADS-B Antenna mounted outdoors on a 12-foot fiberglass push-up mast. I used 50 feet of LMR-400 coax cable terminated with N male connectors outside, and a short adapter cable with N male and SMA male for the connection to the FlightAware receiver. The antenna is compact and very light, so the installation was very easy.
After installing and attaching the outdoor antenna, there was a dramatic difference in the number of signals received, as well as the distance. The PiAware will now receive signals for almost every aircraft flying inside of 1oo nautical mile radius, and is receiving some as far away as 200 miles!