Are you fascinated by the world of radio communication? Whether you're a seasoned ham radio operator, an enthusiast, or just curious about radio technology, understanding the terminology and abbreviations used in the field is essential. This guide provides an extensive list of radio terms and abbreviations that can help you navigate the world of two-way radios, transceivers, antennas, and more.
Let's explore these terms and abbreviations to deepen your knowledge of radio communication:
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Antenna: Signal Transmitter and Receiver. The antenna is an essential component of a two-way radio that both transmits and receives radio signals. It plays a crucial role in the quality and range of communication.
Active Antenna: A physically short or small antenna with a high gain preamplifier; designed for use indoors or in limited space areas.
Active antennas offer advantages such as signal gain, noise reduction, resistance to signal attenuation, multi-frequency coverage, and enhanced interference resistance.
Active Filter: A circuit eliminating unwanted audio frequencies in a receiver.
Address: The information in a packet specifying the intended receiving station.
AGC (Automatic Gain Control): Automatic Gain Control is a feature in HF transceivers that automatically adjusts the receiver's gain based on the strength of the received signal. It helps maintain consistent audio levels and reduces distortion.
Amplitude Modulation (AM): A modulation technique that varies the power output of a transmitter by the variations in the modulating audio signal.
Amplification: The process of increasing the strength of a radio signal.
AMTOR (Amateur Teleprinting Over Radio): A mode that uses FSK to send messages with error detection capabilities and request retransmission of missing or corrupted data.
ANARC (Association of North American Radio Clubs): An association of radio listener clubs in the United States and Canada.
Active Noise Cancellation (ANC): ANC is a technology in CB radios that minimizes background noise. It employs a microphone to detect external sounds and produces opposing sound waves to eliminate the noise, significantly enhancing audio quality. This is especially valuable in noisy settings like vehicles, ensuring clearer communication for CB radio users. However, it's important to recognize that the availability and performance of ANC can differ based on the CB radio model.
Antenna Tuning Unit (ATU): A device installed between a receiver or transmitter and the antenna to match the radio impedance to the antenna impedance for maximum power transfer.
ARRL (American Radio Relay League): The national association for ham radio operators in the United States.
Attended Operation: Operation of a radio station with a human operator at the control point.
Attenuator: A circuit to reduce the sensitivity of a receiver in fixed steps measured in decibels.
Antenna Tuning Unit (ATU): A device that matches the radio impedance to the antenna impedance for maximum power transfer.
Automatic Gain Control (AGC): A receiver circuit that adjusts the amount of amplification given to a received signal so that the volume from the speaker stays relatively constant.
Bandspread: A form of electronic (not mechanical) fine-tuning common on tube-era general coverage receivers. Usually, the ham bands were "spread" to achieve better frequency display accuracy than the main tuning dial could provide. The proper setting of the main dial was critical.
Bandwidth: The amount of frequency space occupied by a radio signal.
Battery Saver Mode: Battery saver mode is a power-saving feature found in many two-way radios. When activated, it reduces the power consumption of the radio by adjusting transmit power or implementing intermittent transmission, prolonging battery life.
Baud: The rate at which data is transmitted measured in bits per second.
Beacon: A station making one-way transmissions for navigation, homing, and propagation indication purposes.
Beam Antenna: An outdoor antenna, usually mounted on a rotor, that concentrates more transmitter power (or receives better) in a certain direction.
Beat Frequency Oscillator (BFO): A receiver circuit that generates a replacement carrier to enable intelligible reception of CW, FSK, and SSB signals.
Calling Frequency: An agreed-upon frequency where stations attempt to contact each other; once contact is made, stations move to a working frequency.
Call Sign: A group of letters and numbers used to identify a station and the country authorizing its operation.
Carrier: The unmodulated output of a radio transmitter.
CB (Citizens Band): The Citizens Band, or CB, refers to a range of radio frequencies set aside for public use. CB radios operate within this band and are popular among truckers, off-road enthusiasts, and individuals requiring short-distance communication.
Center Frequency: The unmodulated carrier frequency of an FM transmitter.
Center Loading: Placing a loading coil at the center of an antenna to lower the antenna’s resonant frequency.
Channel: The frequency on which a radio transmission takes place, or the input and output frequency pair used by a repeater station.
Circular Polarization: An antenna design where polarization switches rapidly between horizontal and vertical.
Closed Repeater: A repeater station that may be used only by stations belonging to a certain organization or group; access is usually restricted by tone access.
Co-Channel Interference: Interference from stations on frequencies adjacent to the desired signal.
Coded Access: A method of restricting access to a repeater station to stations that begin their transmission with a special sequence of tones.
Collision: When two or more packet radio stations simultaneously attempt to transmit on the same frequency.
Connected: Term used to describe a successful contact between two packet radio stations and the exchange of packets between them.
Continuous Wave (CW): The constant output of a radio transmitter that can be periodically interrupted to send messages by Morse code.
CQ: A general call sent by a station to any other station that may receive it. Hams and other stations "call CQ" to indicate they will answer any station replies to their call.
Crystal Filter: A filter that uses a network of piezoelectric crystals to obtain high rejection of unwanted signals.
CTCSS (Continuous Tone-Coded Squelch System): CTCSS is a feature found in two-way radios that allows users to selectively filter out unwanted transmissions by using sub-audible tones. It helps minimize interference from other users sharing the same frequency.
Cut Numbers: A system of sending numbers via Morse code by substituting shorter letter characters for longer number characters.
Cutoff Frequency: The frequency at which a filter will begin to reject signals.
dB: Abbreviation for decibel.
DCS (Digital-Coded Squelch): DCS is another squelch system that uses digital codes instead of tones to prevent unwanted signals from opening the receiver. It provides a more secure and reliable means of communication by reducing false activations.
Delay: How long a scanner radio pauses on a channel to await another transmission.
Digipeater: A packet radio station that receives and retransmits packets intended for other stations.
Digital Modes: Digital Modes are communication modes that use digital encoding and decoding techniques to transmit data over HF frequencies. Examples of digital modes include PSK31, RTTY, and FT8.
DSP (Digital Signal Processing): Digital Signal Processing is a technology used in modern HF transceivers to enhance received audio quality, reduce noise, and improve overall signal performance through digital processing techniques.
DTMF (Dual-Tone Multi-Frequency): It is a signaling technique used in two-way radios and telecommunication systems. It allows users to send signals by pressing specific combinations of keys on their radio or telephone keypad.
Dual Watch: Allows the user to choose 2 priority channels to scan.
Duplex: Simultaneous Transmit and Receive. Duplex operation refers to the ability of a two-way radio to transmit and receive simultaneously. It enables natural and uninterrupted conversation between users without the need to switch between transmit and receive modes.
DX (Distant Station): DX is a term used to refer to long-distance radio communication. DXing involves making contacts with distant stations, often in different countries or continents, using HF transceivers.
DXCC(DX Century Club): An award given by the ARRL to hams who contact other hams in at least 100 different countries.
Dynamic Range: How well a receiver can handle strong signals with overloading; any measure of over 100 decibels is considered excellent.
ERP (Effective Radiated Power): The output of a transmitter multiplied by the gain of an antenna.
Emergency Alert: Emergency alert is a feature found in certain two-way radios that enables users to send distress signals or emergency notifications to a designated group or channel. It ensures a quick response and assistance during critical situations.
Encryption: Secure Communication. Encryption is the process of encoding transmitted signals to prevent unauthorized access and ensure secure communication. Encrypted two-way radios provide an additional layer of privacy and confidentiality.
Eyeball: Slang for a face-to-face meeting between two ham radio operators or radio hobbyists.
FCC(Federal Communications Commission): The FCC is the regulatory body in the United States responsible for managing and licensing radio frequency spectrum. They establish guidelines and regulations to ensure efficient and interference-free communication.
Feedline: The cable connecting a radio to an antenna.
Filter: A circuit or device that will allow certain frequencies to pass while rejecting others.
FM (Frequency Modulation): A modulation technique that varies the carrier frequency of a transmitter by the variations in the strength of the modulating audio signal.
FRS (Family Radio Service): The FRS is an unlicensed radio service intended for short-range communication among family members and recreational users. FRS radios operate on a specific set of channels and are limited to low-power output.
Full Quieting: An FM radio signal strong enough to completely quiet the receiver background noise.
Gain: The apparent increase in the strength of a signal radiated or received by an antenna caused by the antenna having better performance in some directions than others.
Gallon: Slang for the maximum transmitter power authorized for ham radio operators.
Gateway: A node that is a part of more than one network and can be used to pass messages between those networks.
General Coverage: A term used to describe receivers and transmitters covering at least the frequency range of 500 kHz to 30 MHz and capable of operation in several different modes, including AM, CW, and SSB.
GHz (Gigahertz): It's a unit equal to 1000 megahertz or 1,000,000 kilohertz.
GMRS (General Mobile Radio Service): GMRS is a licensed radio service available in the United States that allows for communication over longer distances. It requires obtaining an FCC license and is commonly used by businesses, organizations, and outdoor enthusiasts.
GMT (Greenwich Mean Time): Abbreviation for Greenwich Mean Time, a time standard that represents the mean solar time at the Prime Meridian.
Groups: Radios with many channels break the channels up into sets called Zones or Groups. On most radios, there are 16 channels in each group.
Hamfest: A large gathering of ham radio operators and other radio hobbyists.
Hz (Hertz): One complete cycle of a radio wave per second.
HF (High Frequency): High Frequency refers to the range of radio frequencies from 3 to 30 megahertz (MHz). HF transceivers operate within this frequency range, allowing for long-distance communication.
Homebrew: A slang term for home-built, noncommercial radio equipment.
ID: Abbreviation for "identification."
Impedance: The opposition to the flow of electric current and radio energy; it is measured in ohms (Ω). For best performance, the impedance of an antenna, the feedline, and the antenna connector on a radio should be approximately equal.
Input Frequency: The frequency on which a repeater station listens for signals to retransmit.
IP Rating (Ingress Protection Rating): The IP rating is a standard established by the International Electrotechnical Commission (IEC) that classifies the level of protection provided by electronic devices against solid objects and liquids. It evaluates the protection ability of electrical equipment against dust and water. The IP protection level comprises of two numbers: the first number indicates the dust protection level, while the second number indicates the waterproof rating. The higher the waterproof rating number, the better the protection against water.
kHz (kilohertz): Unit equal to 1000 hertz.
kW (kilowatt): Unit equal to 1000 watts of transmitter power.
Lockout: To remove certain channels from the scanning sequence of a scanner.
Longwave: Radio signals 300 kHz and lower in frequency, although this term is often used to mean any radio signal lower than 540 kHz.
Loop Antenna: A physically small receiving antenna usually designed for indoor use and tuning frequencies below 5 MHz; it receives in a figure-8 pattern.
LSB (Lower sideband): The sideband is lower in frequency than the transmitter’s carrier.
Low Pass Filter: A filter that rejects all frequencies above a certain point but allows all lower frequencies to pass.
LUF (Lowest Usable Frequency): The lowest frequency that can support propagation between two points.
Medium Wave: Radio signals from 300 to 3000 kHz, although this term is often used to mean any radio signal in the AM broadcast band (540 to 1700 kHz).
Megahertz: Unit equal to 1,000,000 hertz or 1000 kilohertz.
Megawatt: Unit equal to 1,000,000 watts of transmitter power.
MHz (megaHertz): Unit equal to 1,000,000 Hz. In older publications, it may show as Mc for megacycle or 1,000,000 cycles per second.
Mic Gain/Microphone Gain: Mic gain is a control on 10-meter radios that adjusts the sensitivity of the microphone. It determines the audio input level and affects the transmitted audio quality.
Modulation: The process of altering the output carrier of a transmitter in some way to convey information.
Multiband Antenna: An antenna suitable for operation on several different bands of frequencies.
NOAA Weather Channels: NOAA (National Oceanic and Atmospheric Administration) weather channels are specific frequencies used to receive weather information, forecasts, and emergency alerts. Some 10-meter radios include NOAA weather channels for weather monitoring purposes.
NB (Noise Blanker): A Noise Blanker is a circuit in an HF transceiver that reduces or eliminates pulse-type noise caused by electrical interference. It helps improve the readability of weak signals in the presence of atmospheric or man-made noise.
Notch Filter: A Notch Filter is a filter in an HF transceiver that selectively attenuates or eliminates a narrow range of frequencies. It is used to suppress interference from specific frequencies, such as nearby strong signals.
Omnidirectional Antenna: An antenna that transmits and receives equally well in all directions.
Open Repeater: A repeater station that can be used by anybody; a carrier on its input frequency will automatically be retransmitted on its output frequency.
Output Frequency: The frequency on which a repeater station will retransmit signals it hears on its input frequency.
Overloading: When strong signals in a frequency range interfere with the proper operation of a receiver, creating false "ghost signals" on various frequencies in the frequency range.
Part 15: The section of the FCC’s rules that permits the operation of low-power transmitting devices without a license.
Passband Tuning: A receiver circuit that permits adjusting the bandpass for the best reception under different interference conditions.
Path: The route taken by a signal from the transmitting station to the receiving station.
PEP (Peak Envelope Power): Peak Envelope Power is the maximum power that an HF transceiver can deliver during short-duration signal peaks. It is an important specification for understanding the power capabilities of a transceiver.
Phase Modulation: Similar to FM, this modulation technique varies the carrier frequency of a transmitter by the strength and frequency of the modulating signal.
PTT (Push-to-Talk): PTT refers to a button or switch on a two-way radio that must be pressed to initiate transmission. Releasing the PTT button allows the user to listen to incoming messages.
QRL: Radiotelegraph abbreviation meaning "this frequency is busy."
QRM: Radiotelegraph abbreviation meaning "interference."
QRN: Radiotelegraph abbreviation meaning "static."
QRO: Radiotelegraph abbreviation meaning "increase transmitter power."
QRP: Radiotelegraph abbreviation meaning "reduce transmitter power."
QRS: Radiotelegraph abbreviation meaning "send more slowly."
QRT: Radiotelegraph abbreviation meaning "stop transmitting."
QRU: Radiotelegraph abbreviation meaning "I have no messages for you."
QRV: Radiotelegraph abbreviation meaning "I am ready to communicate."
QRX: Radiotelegraph abbreviation meaning "wait."
QRZ: Radiotelegraph abbreviation meaning "who is calling me?" It is also used to solicit the next contact in a series of contacts.
QSL: Radiotelegraph abbreviation for "I confirm," refers to a card or letter confirming that a contact did take place between two stations or that a listener did indeed hear a certain station.
QSO: Radiotelegraph abbreviation for a contact between two or more stations.
QSY: Radiotelegraph abbreviation for "change frequency."
QST: Radiotelegraph abbreviation for a transmission directed to all ham radio operators; it is also the name of the ARRL’s monthly magazine.
Ragchew: Slang for an informal conversation via radio.
Repeater: A radio station that receives stations on a certain frequency and simultaneously retransmits them on another frequency.
RF Gain: A control used to continuously vary the sensitivity of a receiver.
Rubber Ducky: Slang for a shortened flexible antenna used with hand-held scanners and transceivers.
Scan: Scanning is a function that allows a two-way radio to cycle through multiple channels to monitor for incoming transmissions. It ensures that users do not miss important messages on different frequencies.
Scanner: A radio receiver that automatically tunes through a sequence of user-selected frequencies.
Search: A feature in certain receivers that will scan a frequency range at certain increments (such as 1 or 5 kHz) and pause on any frequency where a signal is present.
Selectivity: How well a receiver can reject signals on frequencies adjacent to the one you want to tune. It is indicated by several decibels rejection at a frequency point away from the desired signal.
Sensitivity: How well a receiver responds to weak signals, measured in microvolts (mV); the lower the number of microvolts indicated, the more sensitive the receiver.
SHF: Abbreviation for super high frequencies.
Shortwave: Frequencies in the high frequencies region of 3 to 30 MHz, but this term is often used to refer to frequencies from 1.7 to 30 MHz.
Sideband: A signal equal to the bandwidth of the modulating frequency found above and below the carrier frequency in an AM signal.
Sidewinder: Slang for an SSB station.
Simplex: To transmit and receive on the same frequency.
Single Sideband (SSB): A modulation technique, which, when harnessed by advanced transceivers, brilliantly suppresses one sideband and the carrier, transmitting only the remaining sideband. This not only optimizes spectrum utilization but also enhances long-distance communication quality, making it an essential feature for amateur radio enthusiasts and professionals.
S-meter: Signal Strength Meter: A meter or bar graph that indicates the relative strength of a received signal.
Spread Spectrum: A modulation method that spreads transmitter energy across a relatively wide frequency range according to a modulating code.
Squelch: A circuit in a radio receiver that quiets the receiver until the strength of a received signal exceeds a specified level.
SWL: Abbreviation for "shortwave listener."
SWLing: Abbreviation for "shortwave listening."
SWR(Standing Wave Ratio): The ratio of power sent down a feedline from the transmitter to the power reflected through the feedline to the transmitter. A ratio of 1:1 is ideal; anything higher than 2:1 usually indicates a problem in the feedline or antenna.
Time-out: To transmit too long in a single transmission, causing a repeater’s timer circuit to stop further transmissions.
Tone Access: A method of activating a repeater station that requires transmission of a brief tone before all transmissions are relayed.
Top Loading: Placing a loading coil at the top of an antenna to lower the antenna’s resonant frequency.
Transceiver: A transceiver is a combined device that incorporates both a transmitter and a receiver in a single unit. It enables users to transmit and receive radio signals using a single device.
Translator: A device that receives multiple signals within a certain frequency range and simultaneously retransmits them in another frequency range.
Transponder: A device that will emit a radio signal when it receives a radio signal on a certain frequency.
Transverter: A device that takes one signal in a specified frequency range and simultaneously retransmits it in another frequency range. (This differs from a translator, which can handle more than one signal.)
UHF: Abbreviation for ultra-high frequencies.
UHF low: The frequency ranges from 450 to 470 MHz.
UHF-T: The frequency ranges from 470 to 512 MHz.
Ultra High Frequencies: The frequency ranges from 300 to 3000 MHz.
Unity Gain: An antenna that gives no gain or loss; its effective radiated power is equal to the transmitter power applied to it.
Upper Sideband (USB): The sideband is higher in frequency than the transmitter’s carrier.
Vertical Polarization: An antenna that radiates, or receives best, radio waves having their electric field perpendicular to the Earth’s surface.
Very High Frequencies: The frequency ranges from 30 to 300 MHz.
VFO (Variable Frequency Oscillator): A circuit used to set the frequency of a receiver or transmitter.
VHF: Abbreviation for very high frequencies.
VHF High Band: The frequency ranges from 150 to 175 MHz.
VHF Low Band: The frequency ranges from 30 to 50 MHz.
VOX: A circuit that can turn a transmitter on and off automatically whenever someone speaks into the microphone.
Wavelength: The distance between the same points on two consecutive radio waves.
Work: To communicate with another radio station or station.
Working Frequency: A frequency that two or more stations can use to communicate with each other.
"10-4" is a widely recognized CB radio code that signifies acknowledgment or understanding of a received message. It is commonly used to indicate agreement or confirmation.
Two-way radios are versatile communication devices that offer reliable, instant, and portable communication over short distances. Whether you need to stay connected during outdoor adventures or require efficient coordination in professional settings, a two-way radio is a valuable tool to consider.
By understanding the key features, terminology, and practical applications of two-way radios, you can make informed decisions when selecting the right device for your specific needs.
For more information and expert advice on two-way radios, stay tuned for our upcoming articles and guides.
