40-meters: 7MHz to 7.3MHz
(+): positive (power supply input)
(-): negative (power supply input)
A3A: Mode of single sideband with -16dB pilot carrier
A3H: AME or AM compatible (carrier with only upper sideband)
A3J: Telephony; single sideband with suppressed carrier
AGC: Automatic gain control which prevents receiver overload
ALC: Automatic loading control which prevents transmitter overload
AMTOR: Amateur radio equivalent of SITOR with slightly different standards
ATTN: Attenuator which reduces a received signal
ADSP: Adaptive Digital Signal Processing; exclusive to SGC, a DSP technology which processes the signal to eliminate unwanted noise and improve incoming signal sound clarity
AM: Amplitude modulation, low efficiency type of radio transmission generally used for broadcast AM radio station bands with 100% carrier inserted
AMVER: Coast Guard operated system for rescue "automated mutual assistance vessel rescue system"
AM broadcast band: A band ranging from 530 to 1605 KHz.
Amateur bands: HF frequencies of 1.8MHz to 29.7 MHz set aside for amateur radio operators.
Amplitude: The height of a radio or sound wave "loudness".
Amplitude Modulation: Adding information to an RF carrier by increasing and decreasing amplitude.
Analog: Representing data with physical quantities (a watch with hour and minute hands is an analog time display).
Antenna: Any part of any SSB system that radiates radio energy
ARQ: Automatic Repeat Request; a mode to compare transmission; a repeat signal is sent only when requested by the receiving station
Band: A range of frequencies, usually within a one MHz span
Bank: A collection of channels to be scanned as a group in order
Binary: A system of numbers represented only by digits 0 and 1. (Contrast with decimal which uses digits 0 through 9.)
Capacitor: A device to store electrical energy.
Carrier: An unmodulated RF signal.
Chassis GND: Chassis or cabinet ground
CLAR: Clarifier; allows receiver frequency to be offset slightly from transmitter frequency
COMM: Communication; also used to reference serial communications computer port
CW: Continuous wave; to transmit the mode of Morse code
Crystal: A piece of quartz mineral that will resonate at a particular frequency and used as a reference in transceivers
COAX: Coaxial cable, an electrical conductor which carries radio energy from a transmitter to an antenna system; the inner conductor is insulated from an external wire mesh shield
Chip: A wafer of semiconductor material used in an electronic circuit.
Copy: When radio operators hear and write down a message, they "copy."
DATA I/O: Data input/output
DC: Direct Current
DUPLEX: A method of frequency in which ship stations transmit on one frequency while shore stations transmit a different frequency
DSP: Digital signal processing; technology which eliminates unwanted noise to enhances a signal
DXpedition: A trip taken by an amateur radio operator to a uniquie location, a contest to try to reach distant stations.
FEC: Forward error correction; a mode to compare transmission; each character is sent twice and the redundancy of the code serves as the check
Feedline: The method of connecting the antenna to the radio
Frequency: The number of polarity alternations per second measured in Hertz. KHz = thousand Hertz; MHz = million Hertz
FM: Frequency Modulation
FWD: Forward transmit power going to the antenna
Gain: The amount of amplification a system has; in antenna systems, the gain is the measurement of the directional characteristics
Ground: A connection to earth or an earth counterpoise, non-conductive
Groundplane: An artificial ground used for antenna systems
Groundwave: A radio signal that travels along the earth, bending over the horizon
GMT: Greenwich Mean Time (universal time) the international standard time referred to the zero degree meridian
Heterodyne: The frequency that results when two radio frequencies "beat" together (one frequency minus the second frequency = heterodyne).
Hertz: See Hz.
HF: High Frequency, a range of frequencies from 3 to 30 MHz.
Hz (Hertz): A measure of frequency: one cycle per second
Inductor: A coil onto which voltage is imposed by another 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 in the 2 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 sideband) by imposing a mirror-image frequency so the two cancel each other.
PTT: Push to Talk, a common radio function
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 generally used for long distance communications where energy is not radiated until modulation is present
Simplex: A method of frequency use in which stations transit 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 transmitting over radio"
Skip: The bounce of the radio signal off the ionosphere
Skywave: A radio signal which is projected into the ionosphere and bounces one or more times before returning to earth
Synthesize: The device that produces and controls frequencies through synthetic results
SNS: Exclusive to SGC; spectral noise subtraction; works with DSP in signal processing to improve incoming signals
TELEX: A commercial service involving teletypewriters connected through automatic exchange; "teleprinter + exchange"
Transceiver: A term applied to equipment that both transmits and receives
USB: Upper Sideband
UTC: Coordinated Universal Time; same as GMT
VCO: Voltage Controlled Oscillator
VHF: Very High Frequency; commonly refers to a short range type of radio whose signal is transmitted on a line of sight from antenna to antenna
VSWR: Voltage Standing Wave Ratio; a measurement of the efficiency of an antenna system; it measures the energy which is projected out and reflected back to the antenna
Voltage: A measurement of electrical pressure of the current times resistance
VDC: Voltage Direct Current
Wavelength: Distance between two successive radio waves
Work: To be in radio contact or communication with another station