Brenda Ann wrote:
I believe that aircraft (in the US, at least) are all required to have a VHF
air band radio, just as all marine craft are required to have a VHF Marine
band radio (this, AFAIK, includes boats on waterways that carry commercial
traffic, but not necessarily on small waterways or such. Large lakes and
reservoirs may or may not have this requirement, but I know anything that
sails on the ocean or major river (Columbia, Mississippi, etc.) it is
required.

There probably is a size requirement as it makes no sense that a two
person boat with an electric motor would be required to have one.

Many boats have CB's also because they are cheap, unlicensed, and much
longer range than VHF. I don't know about other types, but GSM cell
phones are limited to 35 km due to timing issues. In some parts of
Australia, it has been extended to 70km by reducing the number of
conversations a channel can support (widening the time slot), but I have
never heard of it being done on coastal cells.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM