I wasn't suggesting the use of worldwide radio transmissions for R/C!! That would be ridiculous. You asked about the range of different frequencies, and I was providing some examples. For R/C use, we are restricted to relatively low-power transmissions, anyway.

Spread-spectrum technology (which is used in Spektrum R/C equipment) can also used for some Ham radio communications. The benefits are the same -- no intereference.

- Jeff