Technical information

74
© 1998 SGC Inc
SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
P.O.Box 3526, 98009 Fax: [phone] or 746-7173 Tel: [phone] or 1-800-259 7331
E-mail: [e-mail] Web site: http://www.sgcworld.com
HF: A range of frequencies from 3 to 30 MHz.
Hz (Hertz): A measure of frequency: one cycle per second.
INDUCTOR:Electronic component that stores energy in a magnetic field,
usually a coil.
IMPEDANCE: The apparent opposition in an electrical circuit to the flow of
an alternating current.
IONOSPHERE: Electricity conducting layers in the earth's upper
atmosphere.
KHz: 1000 Hertz.
LCD: Liquid crystal display.
LPA: Linear power amplifier.
LSB: Lower sideband.
LED: (Light-Emitting Diode) A semiconductor that lights up; used in digital
displays.
MEMORY: A computer memory address to which channel information may
be assigned.
MHz: 1 million Hertz.
MF: (Medium Frequency), a band of frequencies 300 KHz - 3 MHz range
used for short range communications.
MICROPROCESSOR: A computer processor contained on a chip.
MODULATION: The process of varying the amplitude, frequency or phase
of a carrier or signal.
OSCILLATOR: A device that produces alternating current.
OSCILLOSCOPE: A display of frequency on a cathode ray tube.
PCB: Printed circuit board.
PHASE-SHIFT: Removing an unwanted frequency (or side band) by
imposing a mirror-image frequency so the two cancel each other.
PTT: Push to talk.
PEP: Peak envelope power; commonly a power output rating.
PROPAGATION: The characteristics of different radio frequency
transmissions, generally in regard to usable distance in relation to
frequency and time of day.
RF: Radio frequency; any frequency higher than a person can hear.
RESONATE: The frequency that a circuit is tuned to
RADIATE: The movement of energy away from a place, as in the radiation of
an antenna.
SSB: Single Side Band; a high efficiency type of radio transmission general
ly used for long distance communications where energy is not radiated
until modulation is present.
SQL: Squelch.
SIMPLEX: A method of frequency use in which stations transmit and receive
on the same frequency.
SITOR: A commercial system of radio teletype for ship to shore, ship to ship
and between ships and any telex subscriber; "ship international