The International Telecommunications Union radio regulations, as
amended by the 1971 conference and ratified by the United States
Congress, have been in effect in the United States since January 1,
1973.
f. The upper limit of the radio frequency spectrum subject to
international regulations increased from 22 megahertz in 1927 to 40
gigahertz in 1958. Six bands in the range from 40 to 265 gigahertz
are shared coequally by aeronautical mobile satellite, maritime
mobile satellite, and aeronautical and maritime radio navigation
satellite service. Additionally, ten other bands above 40 gigahertz
are allocated for space research; two bands for transmitting and
receiving, the balance for receiving only.
8.
Geographical Divisions.
a. Figure 3 shows the three divisions of the world used for
spectrum allocation purposes. The United States and its possessions
fall into Region 2, except for the trust territories which are in
Region 3.
Types of services or allocations may be the same in all
three regions, or they may vary among the regions in accordance with
international agreements, as illustrated by Figure 4. As a result of
such differences, it is possible that a radio set, which technically
and functionally is effective in a military communications system,
can operate in Regions 2 and 3 but not in Region 1.
Services that
share allocated bands, either worldwide or regionally, are listed in
International Telecommunications Union Table of Frequency Allocations
by priority: primary services, permitted services, and secondary
services.
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