A few watts on a nice quiet channel will go many dozens of km just with old fashioned FM voice on handheld transceivers. Put a good directional antenna on one

A few watts on a nice quiet channel will go many dozens of km just with old fashioned FM voice on handheld transceivers. Put a good directional antenna on one end and we're talking over a hundred km. As long as you have line of sight. A few hundred km line-of-sight is fairly unremarkable in itself. Iridium handsets are only like 2 W with compact omnidirectional antennas. Doing this with hardware and protocols not designed for it is pretty cool, though.