Codan Radio Radio Repeater Systems Training Guide - Manual (Page 82)

TRAINING GUIDE | RADIO REPEATER SYSTEM
Appendix J: Glossary of Terms Page 74
Broadband
The ability of a circuit such as an
amplifi er, transmitter, receiver or
antenna to be useful over a wide
frequency range.
Broadband Antenna
A transmitting or receiving antenna
that performs almost uniformly over a
wide frequency band without needing
adjustment.
Call Sign
Identifying letters and numbers for a
radio station or transmitter.
Carrier
A radio wave, current or voltage used
for transmitting intelligence. When no
intelligence is being transmitted, such
as during a pause in communications,
only the unmodulated carrier signal is
present.
Channel
A narrow band of frequencies including
the assigned carrier frequency, within
which a radio system must operate
in order to prevent interference with
stations on adjacent channels.
Conformal Coating
A coating applied to completed circuit
boards to inhibit corrosion and fungus
growths.
Control Station
A base station, the transmissions of
which are used to control the operation
of another fi xed station such as a
repeater. The term is also used, in
the operating context, as the station
operator who directs other operators in
system usage.
Corrosion Inhibitors
Chemicals that inhibit the corrosive
effects of certain atmospheres. e.g.:
moisture.
Crystal
A thin slab of natural or man-made
quartz which, when subjected to the
proper electrical excitation, will vibrate
or oscillate at a specifi c frequency. A
quartz crystal is a major component in
oscillators used in radio transmitters and
receivers.
dB
Abbreviation for decibel. See decibel.
Decibel
A unit of relative voltage or power. One-
tenth of a Bel. Roughly the smallest
change that the human ear can detect.
The decibel is also used to compare
relative differences of signal voltages, or
power.
Decoder
A device that translates coded
intelligence into usable form.
Distortion
Unfaithful reproduction of audio
signals due to changes occurring in
the waveform of the original signal
somewhere in the course of its
transmission, reception or amplifi cation.
Drip Loop
A small circle (20 - 30 cm diameter) of
coaxial cable used at a cable entrance
to a building to discourage the entry of
moisture on the cable surface.
Drop Repeater
A local coverage repeater.
Emission
The process of radiating radio waves
into space from a transmitter.
Encoder
A device that translates intelligence into
a form easier to transmit over a radio
system.
Fade
To decrease gradually in signal strength.
Fade Margin
The difference between the level of
the received signal and the receiver
threshold. Usually expressed in
decibels.