Hams bounce signals off of everything. Aircraft scatter, for example. Probably the coolest is using the ion trails of meteorites. When meteors punch through

Hams bounce signals off of everything. Aircraft scatter, for example. Probably the coolest is using the ion trails of meteorites. When meteors punch through the atmosphere, they create ionized trails. These trails can reflect RF signals. Some of these happen to be optimal at low VFH frequencies, and hams make contacts using frequencies that ordinarily don't work beyond line of sight.