7.
World Administrative Radio Conferences.
a. The allocation of the radio frequency spectrum use by the
diverse radio services is accomplished through World Administrative
Radio Conferences of the International Telecommunications Union. The
International Telecommunications Union table of frequency allocations
is based upon the recommendations of the general membership of the
International Telecommunications Union, and the requirements for
radio services.
In addition to allocating specific bands, such
conferences may also specify that the bands be channelled in such
fashion that only discrete frequencies are available for assignment.
In some instances, such as high frequency aeronautical and high
frequency maritime mobile service, an allotment plan is established
so that specific frequencies may be assigned at only a limited number
of widely separated locations.
In other cases, such as high
frequency broadcasting, the aeronautical mobile services, and the
very high frequency maritime mobile service, channeling plans are
used.
b. The World Administrative Radio Conferences have designated a
number of international distress and emergency frequencies for use
primarily by stations operating in the maritime and aeronautical
mobile services.
Search and rescue operations for manned space
vehicles have also been provided for in the radio regulations, as
amended by the 1971 World Administrative Radio Conferences.
For
aeronautical radio navigation, there is international standardization
on marker beacons, and glideslope bands for instrument landing
systems have been standardized.
c. Frequencies have been allocated for standard frequency and
time broadcasts which provide an accurate source of information for
setting chronometers and for calibration of frequency-sensitive
equipment. Radio Stations WWV near Ft Collins, Colorado, and WWVH in
Hawaii are operated by the United States National Bureau of Standards
to broadcast radio frequencies and time signals.
The transmitted
frequencies of both stations are accurate within one part in ten
billion. Similar stations are operated by both Canada and Japan.
d. The radio regulations also allocate specific bands to receive
radio spectral lines associated with electromagnetic radiation from
stars and other inter- and extra-galactic sources of interest to
science and radio astronomy.
e. The last World Administrative Radio Conference to deal with
the complete set of International Telecommunications Union radio
regulations was held in Geneva in 1959.
Subsequently, several
conferences with limited agendas have been held; space and radio
astronomy in 1963, aeronautical mobile (R) in 1966, maritime
mobile
in
1967,
and
space
telecommunications
in
1971.
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