Idk if it's useful right now to build a ADS-B flight tracker thingy. I sorta want to, but...idk.
There are various configurations that involve a Raspberry Pi and one or two SDR dongles. One for 1090 MHz and the other for 978 MHz.
I totally get that people find it interesting. But I get the impression that some people think this is tactically useful.
I mean, do surveillance drones transmit ADS-B?