18WuD2x

580 radio spectroscope • radiothermics
graph, obtained by scanning the radio spectrum
and plotting signal intensity as a function of frequency
or wavelength.
radio spectrum The continuum of frequencies
useful for radio communication and control.
Classified in the following manner: Very low frequency
(VLF), 9 to 30 kHz; low frequency (LF), 30
to 300 kHz; medium frequency (MF), 300 to 3000
kHz; high frequency (HF), 3 to 30 MHz; very high
frequency (VHF), 30 to 300 MHz; ultrahigh
Decimillimetric
Millimetric
Centimetric
Decimetric
Metric
Decametric
Hectometric
Kilometric
Myriametric
To
infrared,
visible light,
ultraviolet, X rays,
gamma rays
0.1 mm 3 THz
1 mm 300 GHz
1 cm 30 GHz
10 cm 3 GHz
1 m 300 MHz
10 m 30 MHz
100 m 3 MHz
1 km 300 kHz
10 km 30 kHz
30 km 10 kHz
100 km 3 kHz
To lower audio
and subaudio
radio spectrum
EHF
SHF
UHF
VHF
HF
MF
LF
VLF
Microwaves
frequency (UHF), 300 to 3000 MHz; super high frequency
(SHF), 3 to 30 GHz; extremely high frequency
(EHF), 30 to 300 GHz.
radiostat See CRYSTAL FILTER.
radio station 1. The location at which a radio
transmitter and/or receiver is/are installed.
2. The complete set of equipment for a radio receiving
and/or transmitting installation, including
the studio, linking apparatus, and antennas. 3. A
standard broadcast station.
radio technician A professional skilled in the construction,
testing, repair, and maintenance of radio
equipment, and sometimes in its design, and who
usually works under the supervision of a radio engineer.
Also see RADIO SERVICE TECHNICIAN.
radiotelegram See RADIOGRAM.
radiotelegraph 1. Pertaining to the theory and application
of, and the equipment for, Morse code
transmission and/or reception via radio. 2. An
installation for Morse code transmission and/or
reception via radio. 3. The transmission and/or
reception of Morse code signals via radio.
radiotelegraph code See CONTINENTAL CODE.
radiotelegraph distress signal See SOS.
radiotelegraph monitor See KEYING MONITOR.
radiotelegraphy The transmission and/or reception
of telegraphic communications, usually
Morse code, by means of radio.
radiotelephone 1. Pertaining to the theory and application
of, and the equipment for, voice transmission
and/or reception via radio. 2. An
installation for voice transmission and/or reception
via radio. 3. The transmission and/or reception
of voice signals via radio.
radiotelephone distress signal See MAYDAY.
radio/telephone patch See PHONE PATCH.
radiotelephony The transmission and/or reception
of audio signals, usually human voices, by
means of radio.
radio telescope A directional antenna and associated
equipment for receiving and evaluating the
radio-frequency electromagnetic radiation from
space—especially from celestial objects (such as
the sun, planets, stars, nebulae, galaxies,
quasars, etc.). See RADIO ASTRONOMY.
radioteletype 1. Pertaining to the theory and application
of, and the equipment for, text data
transmission and/or reception via radio. 2. An
installation for text data transmission and/or reception
via radio. 3. The transmission and/or reception
of text data signals via radio.
radioteletypewriter A teletypewriter adapted to
radio, rather than wire service; it is used in some
RADIOTELETYPE installations. In recent years,
personal computers and terminals have largely
replaced adapted teletypewriters for this purpose.
radiotherapy The use of X rays and/or radioactive
substances in the treatment of disease and disorders.
radiothermics The science of the generation of
heat by means of radio-frequency current.