Radio Term
| ACC | (ACCessory) |
| Adjacent-channel interference | When a receiver is tuned to a specific frequency and interference is received on a nearby frequency. |
| AF | Audio Frequency |
| AFC | Automatic Frequency Control) Automatically compensate frequency drift. |
| AFSK | Audio Frequency Shift Keying |
| AGC | Automatic Gain Control) Automatically optimize receiver amplifier gain |
| ALC | Automatic Limiting Control) Limits RF drive level to power amplifier during transmit to prevent distortion |
| AM | Amplitude Modulation |
| AMSAT | AMateur SATellite |
| AMTOR | (AMateur Teleprompting Over Radio) A form of RTTY, radio Teletype |
| ANF | Automatic Notch Filter |
| ANL | (Automatic Noise Limiter) Eliminates impulse and static noise peaks. |
| ANT | ANTenna |
| Antenna ground system | Term used for a RF reference potential for some types of antennas. Most unbalanced or asymmetrical antennas need a Good RF ground. |
| Antenna impedance | The impedance of an antenna at its resonance. Although an Antenna’s impedance fluctuates with the frequency of operation, an antenna should be 50 ohm for most transceivers |
| Antenna matching | When the antenna’s impedance at resonance is at optimum Performance for your transmitter output circuit. |
| Antenna tuner | Device used to match an antenna to the output impedance of a transmitter |
| APC | (Automatic Power Control) Current limiting of power amplifier to prevent damage to finals in high SWR conditions. |
| APRS | Automatic Position Reporting System In conjunction with a GPS and TNC provide position reporting. |
| ARES | Amateur Radio Emergency Service |
| ARRL | The American Radio Relay League The National Association for Amateur Radio in the |
| ASCII | American National Standard Code for Information Interchange |
| ATT | (ATTenuator) A network designed to reduce the amplitude of a signal. |
| ATV | Amateur Television |
| FSTV | Fast Scan TeleVision |
| SSTV | Slow Scan TeleVision |
| Auto patch | Used in repeater operation for telephone interconnect. |
| Average power | Power measured on standard power meter. |
| Backscatter | Form of ionosphere propagation via the E and F layers allowing stations to hear other stations within the skip zones. |
| Balun | A simple transformer used to change an unbalanced input to a balanced output |
| Band | A range of frequencies. |
| Bandwidth | Frequency needed for particular type of emission. |
| Bank | Memory bank |
| BCI | BroadCast Interference |
| BFO | Beat Frequency Oscillator |
| BNC | Bayonet Neill-Concelman a type of antenna connector |
| BPF | BandPass Filter |
| Boat Anchor | A term used to describe any heavy, big, old, Ham Radio gear can be woking or nonworking condition |
| Busy lockout | Inhibits transmit on a frequency in use |
| Call sign | Sequence of letter and numbers used to identify amateur radio operators and issued by the FCC. |
| CAP | (Civil Air Patrol) Volunteer affiliate of the United States Air Force. |
| Carrier | An unmodulated transmitted signal. |
| Carrier frequency offset | (=Carrier Shift) Distance between mark and space of the carrier for RTTY or similar communications |
| CBR | (Cross Band Repeater) A repeater which receive incoming signal and re-transmit it in different bands— e.g. receives 144 MHz bands and re-transmits 430(440) MHz bands |
| CCW | Counter Clock Wise |
| CH | (CHannel) Sequence of memory positions where frequency and related information is stored. |
| CPU | Central Processing Unit |
| Copy | A term used to indicate a good readable signal |
| CQ | Radio communications term used to call others. |
| CTCSS | (Continuous Tone Coded Squelch System) Adds a continuous sub-audible low frequency tone to the transmitted carrier. Receivers set for the same low frequency tone can decode signal. |
| Cycle | See Khz, Mhz. Ghz |
| CW | Carrier Wave or Continuous Wave. Most Commonly Used With Morse Code Communi-cations |
| CW filter | Used to narrow IF passband to improve reception in crowded band conditions. |
| Data communications | Transfer of data between two or more locations. |
| dBd | Unit of RF power as compared to a dipole antenna. |
| dBi | Unit of RF power as compared to an isotropic antenna. |
| dBm | Decibels measure, 1 mW with a load impedance of 600 OHM (0dBm=1 mW). |
| DC | Direct Current |
| DC ground | A connection point directly to chassis or battery ground to prevent build-up of hazardous DC voltages. |
| Deviation | A measurement for a FM signals for the maximum carrier frequency changes either side of the carrier frequency. |
| Distress call | Signals a life-threatening situation. Most commonly referred to as an SOS or MAYDAY call. |
| Distress frequency | A frequency or channel specific for use in distress calling. Radiotelephone distress frequencies are 2.182 MHz and 156.8 MHz. Survival craft use 243 MHz. Maritime distress frequencies are the same, while general aviation frequencies are 121.5 MHz. |
| Downlink (?Uplink) | Frequency that repeater or satellite transmits on to a user. |
| DSP | (Digital Signal Processor) Used to improve the signal to noise ratio for clearer and more legible communications. Relatively new to the ham radio. Feature reduces unwanted signal noise |
| DTCS | (Digital Tone Coded Squelch) A Selective call system |
| DTMF | (Dual Tone Multi-Frequency (=touch-tone)) Used for transmit/receive numeric information such as phone number, PIN, remote radio control commands etc. |
| Dual watch | Receiving two signals simultaneously. |
| Dummy load | A non radiating 50 ohm load connected to the transmitter to replace the antenna for testing purposes. |
| Duplex | An operation mode in which the transmit and receive frequencies are different. |
| Duplexer | A device which divides transmit and receive signals. |
| Duty cycle | The ratios of transmit to receive time. |
| Dx’pedition | Trip to foreign land to “be DX.” |
| Ears | You Hams Catch this One? (think its some kind of antenna?) |
| EBS | (Emergency Broadcast System) A system where at first an attention tone is transmitted over all station ad the second tone followed with specific instruction regarding the receivable frequency in the national emergency. |
| EEPROM | Electrically Erasable and Programmable Read Only Memory |
| Elmer | A mentor in ham radio, or the ham that helped you get started in ham radio. |
| EME | (Earth-Moon-Earth) Moon bounce communication. |
| EMI | (Electro-Magnetic Interference) Often called RFI (Radio-Frequency Interference). |
| Emission | Transmission of a signal |
| Encryption | Transmitting cryptic form so that only certain people understand what has been sent. |
| Fading | Signal reduction due to atmospherics. |
| Filter | A circuit designed to pass only the desired frequency(s). |
| FM | 1) Frequency Modulation |
| Freeband or FREE BAND | (A section of frequency that was claimed by renegades from the C.B. band between 27.405 to 28.000 Mhz.) Also see “Sub Band” 26.965 Mhz. And below!. |
| Frequence | Hz (Hertz) |
| FSK | Frequency Shift Keying |
| FSTV | (Fast Scan TV) Graphics (and audio) communication using TV broadcast signals, requires a wide bandwidth. |
| Full duplex | An operation mode, which transmits and receives on different frequencies at the same time, as a telephone communication. |
| GMT | Greenwich Mean Time (see UTC, Zulu Time) an astronomical time based on the zero time/degrees longitude for different. |
| Ground Plane | A type of Omni-directional antenna |
| Ground Wave | Electrical wave directly travelling from transmitter. |
| Grounding | Electrical connection to the earth. |
| Harmonic | Multiple of a fundamental frequency. |
| HF | (High Frequency) 3–30 MHz range signals. (Normally, 1.9 MHz band also included.) |
| HPF | |
| IC | Integrated Circuit |
| IF | (Intermediate Frequency) Internally converted frequency for amplification and other signal processing. |
| IF shift | A function that electronically shifts IF frequency from a center frequency. |
| IMD | (Inter-Modulation Distortion) Distortion within RF circuits made with upper and lower adjacent channel signals. |
| In The Dirt | An indication that the signal being received is weak or poor, and is just making it over the noise level. |
| KEY | A device used to send Morse Code. |
| Keyer | A device used to send Morse Code that automates the process of sending individual “Dots and Dashes” |
| KICKER | Just to see if all you Hams are reading down this far! (Big Amp I Think? 4KW) |
| LF | (Low Frequency) 30–300 kHz range signals. |
| Li-Ion (Lithium Ion) | Rechargeable battery which has better capacity than Ni-Cd, |
| Lid | A radio operator who is causing intentional problems on the air |
| LPF | |
| LSB | Lower Side Band |
| MARS | Military Affiliate Radio Service(No Not The Planet) |
| Memory bank | A set of memory channels organized into a group. |
| Memory effect | Rechargeable batteries such as Ni-Cd and Ni-MH types may be temporality getting less capacity as a result of repeated non-full charge/discharge cycles. It is called so since rechargeable batteries lose capacity as if “memorize” wrong full capacity level at less than full charge. Li-Ion batteries are free from this effect. |
| MF | (Medium Frequency) 300 kHz–3 MHz range signals |
| MIC | MICrophone |
| Mod or Mod’s | Modifications done to radios to get EXTRA features Common to Hams |
| Modulation | Method of adding information to a radio frequency carrier |
| Morse Code | A form of communication also known as CW |
| Net | A term used meaning a group of hams all on the same frequency, at the same time, taking part in an organized or structured meeting. |
| Net Control | The individual conducting or managing the net. |
| Ni-MH, etc | no memory effect after repeated non-full charge / discharge cycles. |
| Ni-MH | Nickel-Metal Hydride |
| NB | Noise Blanker a function reducing pulse-type noises. |
| NBFM | Narrow Band FM |
| Ni-Cd | Nickel-Cadmium |
| NOAA | (National Weather Service) NOAA Broadcast station transmitting weather related alert signals. |
| Notch filter | Sharp and narrow rejection filter for elimination of interfering Signals |
| NR | Noise Reduction |
| Offset frequency | Frequency difference between transmits and receives. |
| OSC | OSCillator |
| Over Modulated | Common Practice on sound from speker received, |
| PA | Power Amplifier |
| PBT | (PassBand Tuning) A function electronically reduce interference by narrowing IF Bandwidth |
| PEP | Peak Envelope Power |
| Picket Fencing | A term used to describe a signal that is cutting in and out, or hard to copy. |
| PLL | (Phase Locked |
| PTT | Push To Talk as hand microphone |
| PWR | (PoWeR) On – Off Switch |
| Rag Chew | A Ham who likes to talk for a long time! |
| Reflected power | Non-radiated power dissipated as heat when the transmitter is mismatched to the antenna or load. |
| Repeater | Radio systems, which receive incoming signal and re-transmit it for extended communication area. Normally put on geographically high locations for VHF/UHF hand portables. |
| RF | Radio Frequency |
| RF Power | Power at maximum amplitude. |
| RF ground | Connection of amateur equipment to earth ground to eliminate hazards from RF exposure and reduce RFI. |
| RFI | Radio Frequency Interference |
| RIT | (Receiver Incremental Tuning) Fine-tuning receive frequency without changing displayed or memory frequency. |
| Rodger “Beep” | An annoying device used by some people to cause splatter! (see splatter) |
| RTTY | Radio TeleTYpe |
| RX | Receive |
| S/N | Signal to Noise ratio |
| SAR | Search And Rescue |
| Scan | Continually sweeping frequencies looking for signals. |
| Scan Edge | End and start frequencies for a scanning range. |
| Semi Duplex | An operation mode in which transmits and receives is accomplished on different frequencies alternatively. |
| Sensitivity | Indicates how weak a signal the receiver will pick up. |
| Simplex | An operation mode where transmit and receive frequency is same. |
| Sky Warn | Trained volunteer storm spotters for the National Weather Service. |
| SMA | (Sub-Miniature a connector) Type of antenna connector, used in VHF/UHF portable. |
| SP or SPK | Speaker |
| Splatter | A term used to describe excessive distorted,or dirty RF siginal |
| (+ 0r -) | A mode in which the transmit and receive frequency is different. Commenley used in UHF – VHF Repeater Operation. |
| SQL | (SQueLch) A function muting audio output for set conditions. |
| SSB | Single Side Band it has 2 type : 1) USB (Upper Side Band) 2) LSB (Lower Side Band) |
| SSTV | (Slow Scan TV) Graphics communication using narrow bandwidth. |
| SWL | Short Wave Listener |
| SWR | (Standing Wave Ratio) Measurement of forward vs. reflected power output during transmit. |
| TCXO | (Temperature Compensated |
| TNC | 1) Terminal Node Controller Modem for data communication. |
| TOT | (Time Out Timer) AKA Alligator got ya! Time limiting function for continued repeater or other operations. |
| Traffic | Is a term used meaning news or Information of some type |
| TS | (Tuning Step) Incremental steps |
| TSQL | (Tone SQueLch) Squelch function using subaudible tones, selective call. |
| TVI | (TeleVision Interference) CB’ers know about this one well! |
| TX | Transmit |
| UHF | (Ultra High Frequency) 300 MHz–3 GHz range signals. |
| Uplink (?Downlink) | Frequency that user transmits to the repeater or satellite. |
| USB | 1) Universal Serial Bus (If not modulation) |
| UTC | Universal Time Coordinated (see GMT, Zulu Time) an astronomical time based on the zero time/ degrees longitude for different. |
| UFO | What a Ham swears he saw a few beers and a long night at Field Day |
| VFO | (Variable Frequency Oscillator) An operation mode in which operator can change frequency freely. |
| VHF | (Very High Frequency) 30–300 MHz range signals. |
| VOX | (Voice Operated transmission) A function automatically put the transmitter in transmit when talk into a microphone. |
| VSC | 1) Voice Scan Control |
| Weather Alert | NOAA broadcast station transmitting weather related alert signals. |
| WFM | Wideband FM |
| Zulu Time | (see : UTC or UTC) an astro-nomical time based on the zero time/degrees longitude for different. |
