am (amplitude modulation) | a radio transmission mode in which the strength of the speech signal controls the strength of the transmitter signal. This normally resuilts in two sidebands containing the modulation energy. |
ASL (above sea level) | a method of measuring antenna height |
antenna separation | the physical spacing between transmit and receive antennas, when separate antennas are used |
band-opening | a condition that results in greater-than-normal communication range on the VHF and UHF bands |
band-plan | a voluntary system of frequency allocations in each amateur radio band |
Base: | This is the term generally referred to as your home base or base station. The location of your radio transceiver at home. |
break | the word used to interrupt a conversation on a repeater , often to indicate that there is an emergency |
Call sign: | The official FCC assigned call sign that you use in your GMRS system. |
COR (carrier-operated relay) | a device that causes the repeater to transmit in response to a received signal |
carrier | your unmodulated (no speech) transmitter signal |
cavity resonator | a sharply tuned circuit using the physical dimensional resonance of one or more tuned cavities |
channel | the pair of frequencies (input and output) used by a repeater |
channel spacing | the frequency spacing between adjacent frequency allocations - may be 50, 30, 25, 15 or 12.5kHz, depending upon the convention in use in the area of the repeater |
closed repeater | a repeater whose access is limited to a select group (see also open repeater) |
co-channel interference | the interference resulting when a repeater receives signals from a distant repeater on the same frequency pair |
controller | the control system within a repeater which may include turning the repeater on-off, timing transmissions, sending the identification signal, controlling the autopatch & CTCSS encoder/decoder |
control operator | the amateur radio operator who is designated to control the repeater |
courtesy tone | an audible indication that the repeater user may go ahead and transmit |
coverage | the geographic area within which the repeater provides communications |
cross-band | the process of transmitting on one band and receiving on another |
desense (desensitization) | the reduction of receiver sensitivity due to overload from a nearby transmitter |
dropping out | the situation, while using a repeater, when your signal does not have enough strength to keep the repeater triggered. |
duplex | a mode of communication in which you transmit on one frequency and receive on another frequency (see also half and full duplex) |
duplexer | highly selective filter which allows a repeater's transmitter and receiver to share one antenna |
EIRP (effective radiated power referred to isotrope) | ERP plus 2.14 dB to correct for reference to isotrope |
ERP (effective radiated power) | radiated power, allowing for transmitter output power, line losses and antenna gain |
frequency coordinator | an individual or group responsible for assigning channels to new repeaters with minimal interference to existing repeaters |
frequency modulation | a method of modulation, where the strength of the signal is constant, but the frequency varies with the strength of the voice, and the rate of change varies with the frequency of the voice |
full duplex | a mode of communication in which you transmit on one frequency while you simultaneously receive on another frequency |
full quieting | a received signal that contains no noise |
HAAT (height above average terrain) | a method of measuring antenna height |
HT: | An acronym for Handie-Talkie |
half duplex | a mode of communication in which you transmit at one time on one frequency and receive at another time on another frequency |
hand-held | a portable transceiver small enough to fit in the hand, clipped to your belt, or in your shirt pocket |
handle | slang for your name (not recommended) |
helical resonator | a compact resonant filter circuit to block multiple interfering signals |
horizontal polarization | the antenna elements are horizontal (used at vhf/uhf for weak signal CW/SSB operation) |
Hz (Hertz) | a unit of frequency measurement equal to one cycle per second |
ID (identification) | the means by which a station identifies its call sign by Morse code or speech |
input (frequency) | the frequency of the repeater's receiver |
intermod (intermodulation distortion or IMD) | interference that results when strong signals from nearby transmitter (s) mix with the desired signal in a radio receiver |
isolation | the difference in level (measured in dB) between a transmitted and received signal due to filtering |
isotrope | a theoretical antenna with zero dimensions and a spherical radiation pattern. Gain is -2.14 dB from dipole |
jamming | the action of deliberate illegal interference with a repeater operation |
kHz (kilohertz) | a unit of frequency measurement equal to 1,000 cycles per second (Hertz) |
kerchunk | to key up a repeater without identifying |
key up | to turn on the repeater by transmitting on its input frequency |
MHz (megahertz) | a unit of frequency measurement equal to 1,000,000 cycles per second (Hertz) |
machine | a slang expression meaning a repeater system |
magnetic mount (mag-mount) | an antenna with a magnetic base that permits quick installation and removal from a metallic surface, including an automobile body |
modem (modulator-demodulator) | an interface device for use between computers. See TNC |
negative offset | the repeater input frequency is lower than the output frequency |
NiCd (or NicCad) | a nickel cadmium battery that may be recharged many times; often used in handheld transceivers |
NiMH | new technology nickel metal hydride battery that has advantages over NiCd, but is more expensive |
odd split | unconventional frequency separation between input and output frequencies. |
open repeater | a repeater whose access is not limited |
out | indicates the end of a contact |
output frequency | the frequency of the repeater's transmitter (and your receiver) |
Portable: | Carrying radio with you, or refers to a hand held radio. |
positive offset | the repeater input frequency is higher than the output frequency |
Private | This system is also found with groups, as wall as clubs, businesses, families, and other organizations. Outside persons should request permission to use this system, and may sometimes be required to pay monthly or yearly dues to help maintain the system. |
ptt (push to talk) | the use of the microphone button or control line to key the transmitter on |
radio direction finding (RDF) | the art and science of locating a transmitter |
raster | the vertical spacing of television scanning lines. Used also as slang for channel spacing |
repeater | an automatic relay station, generally in a high location, which is used to increase the range of mobile and handheld FM transmitter/receivers |
repeater directory | a repeater list for a particular area (RAC publishes one for Canada and neighbouring states) |
rubber duck(y) | slang term for the flexible rubber-covered antenna supplied with handheld radios |
sked (schedule) | a prearranged (scheduled) contact between two stations |
separation (split) | the difference, in kHz, between the repeater's transmit & receive frequencies. Conventional separations by amateur band are: 29 MHz - 100 kHz; 50 MHz - 1 MHz; 144 MHz - 600 kHz; 220 MHz - 1.6 MHz; 440 MHz - 5 MHz; 902 MHz - 13 MHz; 1270 MHz - 12 MHz. |
simplex | a mode of communication in which you take turns to transmit and receive on the same frequency. A frequency set aside for non-repeater use. |
squelch | a circuit within a radio that keeps the speaker silenced (squelched) until the signal level exceeds a certain point, set by the squelch control. Normally you set the squelch to just block out noise & allow signals to pass. |
tail | the brief signal transmitted by a repeater transmitter after someone stops talking. |
Talk Around: | Same as communicating direct except you are doing so on a repeater output frequency. |
time-out | to cause the repeater, or a repeater function, to turn off because you have transmitted too long |
timer | a device which measures the length of each transmission & causes the repeater, or a repeater function, to turn off, after a transmission has exceeded the preset time. |
translator (linear translator) | a device used to directly convert and retransmit a block of received frequencies |
uhf (ultra high frequency) | the region of the radio spectrum between 300 and 1000 MHz or 1 GHz |
vhf (very high frequency) | the region of the radio spectrum between 30 and 300 megahertz (MHz) |
vertical polarization | the antenna elements are vertical (used at vhf/uhf for FM and repeater operation) |
Watt: | The measure of output power for a radio transmitter. |