In article <email@example.com>,
"Green Xenon [Radium]" <firstname.lastname@example.org> wrote:
I think that's a gross oversimplification, an attempt to make
black-and-white a question that encompasses shades of grey.
Radio/microwaves penetrate more substances than IR, but they're no more
or less directed. Substitute a radio-opaque obstacle (e.g. a Faraday
cage) for the wall or body that blocks your IR remote, and the situation
is pretty well the same. Have you never heard a car radio lose its
signal when the vehicle passes under a reinforced-concrete structure?
Take your remote out of its casing and I bet the IR emission becomes
nearly omnidirectional ... OTOH masers emit coherent beams of RF energy.