(45. Answer: frequency, modulation, signals)
46. Radio equipment is generally identified by the frequency band in which
it is designed to operate. The frequency bands the Army usually uses are:
High frequency (HF) __________ between 3 and 30 megahertz
Very high frequency (VHF) __________ between 30 and 300 megahertz
Ultra-high frequency (UHF) __________ between 300 and 3,000 megahertz
Super-high frequency (SHF) __________ between 3 and 30 gigahertz
NOTE: 1,000 megahertz = 1 gigahertz
The abbreviations for the four bands or frequencies commonly used in radio
communications are __________ , __________ , __________ , and __________ .
(46. Answer: HF, VHF, UHF, SHF)
47. Radio is identified not only in terms of frequency or band in which it
is designed to operate, but also in terms of the type of modulation it has.
Radio signals may be frequency modulated (FM), amplitude modulated (AM), or
phase modulated (PM), depending on how the equipment is designed to function.
The three possible types of radio modulation are
(47. Answer: frequency, amplitude, phase)
48. Host radio communication systems in use today are either FM or AM.
However, some of the newer radio equipment features what is called single-
sideband transmission, which is related to AM. Such equipment is often re-
ferred to as SSB or _________ _________________ radio.