What really blows me away is the range that you can achieve with almost no power on tiny little antennas. For instance, ELRS uses a transmitter/receiver that is less than a gram, that can keep a link with a drone alive across 30 km or even more. And the antenna is so small you might toss it away with the packaging if you're not paying attention.
One example:
https://rcmaniak.pl/userdata/public/assets/images/SpeedyBee/...
Oh, and it also speaks WiFi, just in case and it has its own little onboard computer and a web server.