Tossing a battery-powered radio in a gallon ziplock into the woods outside the chainlink for the base also works, and would have more loitering capability than a drone.

Clearly. But it would not be overhead and might suffer from shielding by buildings etc.

So throw it in a gallon ziplock inside some rope and stuff and toss into a tree. In any case, a drone has about 15-30 min of loitering time while a radio-in-a-bag has potentially weeks or even months. I know which I would choose for spying on radio transmissions.

There are geostationary satellites. they loiter.

What they don’t have is high accuracy pointing. If you want to listen to activity on 128MHz at a specific military base from GEO you’re going to be getting a huge amount of interference from everything else in CONUS on the same frequency. At LEO you can do much much better pointing with your antenna.

Geostationary is only possible on very specific orbits - over the equator on one height. Any other orbit cannot be geostationary.