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SUMMARY

Now that you have completed this chapter, a short review of what you have learned is in order. The following summary will refresh your memory of radio-frequency communications terms.

TELECOMMUNICATIONS refers to transmission, emission, or reception of signs, signals, writings, images, or sounds. This is done by visual, oral, wire, radio, or other electromagnetic means.

RADIO COMMUNICATIONS is the term describing teletypewriter, voice, telegraphic, and facsimile communications.

SYSTEM is a combination of sets, units, assemblies, subassemblies, and parts joined together to form a specific operational function or several functions.

SET is a unit or units and the assemblies, subassemblies, and parts connected or associated together to perform a specific function.

GROUP is a collection of units, assemblies, subassemblies, and parts. It is a subdivision of a set or system but is not capable of performing a complete operational function.

UNIT is an assembly or any combination of parts, subassemblies, and assemblies mounted together. Normally capable of independent operation.

ASSEMBLY is a number of parts or subassemblies, or any combination thereof, joined together to perform a specific function.

SUBASSEMBLY consists of two or more parts that form a portion of an assembly or a unit.

PART is one component or two or more components joined together. It is not normally subject to disassembly without destruction.

EXTREMELY LOW FREQUENCY is the band of frequencies up to 300 hertz.

VERY LOW FREQUENCY is the band of frequencies from 3 kilohertz to 30 kilohertz.

LOW FREQUENCY is the band of frequencies from 30 kilohertz to 300 kilohertz.

MEDIUM FREQUENCY is the band of frequencies from 300 kilohertz to 3 megahertz.

HIGH FREQUENCY is the band of frequencies from 3 megahertz to 30 megahertz.

VERY HIGH FREQUENCY is the band of frequencies from 30 megahertz to 300 megahertz.

ULTRAHIGH FREQUENCY is the band of frequencies from 300 megahertz to 3 gigahertz.

SUPERHIGH FREQUENCY is the band of frequencies from 3 gigahertz to 30 gigahertz.

EXTREMELY HIGH FREQUENCY is the band of frequencies from 30 gigahertz to 300 gigahertz.