I currently use my Raspberry Pi to monitor ADS-B transmissions on 1090 MHz. The program that I use is Dump1090-FA. The data that I receive is being fed into the PlanePlotter software on my laptop and I also feed to flightaware.com and adsbexchange.com. For installation instructions see:

https://flightaware.com/adsb/piaware/install

https://www.adsbexchange.com/how-to-feed/

My live feed can be found on: Live ADS-B Feed

Furthermore I use the AirNav ADS-B 1090 MHz antenna and standard RTL-SDR dongle.

PlanePlotter ADS-B feed example