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Glossary.qxd 02.2.5 18:20 Page 1 (1,1)

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GLOSSARY

This is glossary contains general definitions of typical ama- teur terms. Not all of the definition listed may apply to HAM RADIO TERMS your specific model of radio. Consult the manufacture for fur- ther clarification of model-specific terms. Glossary.qxd 02.2.5 18:20 Page 1 (1,1)

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A

ACC (ACCessory) ground system Adjacent-channel interference Term used for a RF reference potential for some types of an- When a receiver is tuned to a specific frequency and interfer- tennas. Most unbalanced or asymmetrical antennas need a ence is received on a nearby frequency. good RF ground. AF (Audio Frequency) Antenna impedance The impedance of an antenna at its resonance. Although an AFC (Automatic Frequency Control) antenna’s impedance fluctuates with the frequency of opera- Automatically compensate frequency drift. tion, an antenna should be 50 Ω for most transceivers. AFSK (Audio Frequency Shift Keying) Antenna matching AGC () When the antenna’s impedance at resonance is at optimum Automatically optimize receiver amplifier gain. performance for your output circuit. ALC (Automatic Limiting Control) Antenna Limits RF drive level to power amplifier during transmit to pre- Device used to match an antenna to the output impedance vent distortion. of a transmitter. AM (Amplitude ) APC (Automatic Power Control) Current limiting of power to prevent damage to fi- AMSAT (AMateur SATellite) nals in high SWR conditions. AMTOR (AMateur Teleprinting Over Radio) APRS (Automatic Position Reporting System) A form of RTTY, radio teletype. In conjunction with a GPS and TNC provide position report- ANF (Automatic Notch Filter) ing. ANL (Automatic Noise Limiter) ARES ( Emergency Service) Eliminates impulse and static noise peaks. ARES is a public-service organization of the ARRL. ANT (ANTenna) ARRL (The American Radio Relay League The National Association for Amateur Radio in the US.

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B A B ASCII (American National Standard Code for Information Inter- Backscatter change) Form of ionosphere propagation via the E and F layers al- A seven-unit digital code for the transmission of teleprinter lowing stations to hear other stations within the skip data. zones. ATT (ATTenuator) Balun A network designed to reduce the amplitude of a signal. A simple transformer used to change an unbalanced input to a balanced output. ATV (Amateur ) FSTV, SSTV Band A range of frequencies. Auto patch Used in operation for interconnect. Frequency needed for particular type of emission. Average power Power measured on standard power meter. Bank Memory bank BCI (BroadCast Interference) BFO (Beat Frequency Oscillator) BNC (Bayonet Neill-Concelman) A type of antenna connector BPF (BandPass Filter) Busy lockout Inhibits transmit on a frequency in use

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C

Call sign CQ Sequence of letter and numbers used to identify amateur Radio communications term used to call others. radio operators and issued by the FCC. CTCSS (Continuous Tone Coded Squelch System) CAP (Civil Air Patrol) Adds a continuous sub-audible low frequency tone to the Volunteer affiliate of the United States Air Force. transmitted carrier. Receivers set for the same low frequency Carrier tone can decode signal. An unmodulated transmitted signal. CW Carrier frequency offset (=Carrier Shift) 1) Distance between mark and space of the carrier for RTTY or 2) ClockWise similar communications. CW filter CBR (Cross Band Repeater) Used to narrow IF passband to improve reception in crowded A repeater which receive incoming signal and re-transmit it in band conditions. different bands— e.g. receives 144 MHz bands and re-trans- mits 430(440) MHz bands. CCW (Counter ClockWise) CH (CHannel) Sequence of memory positions where frequency and related information is stored. CI-V Icom Control Interface allows multiple radio control simultaneously. Conversion Number of IF circuits in the receiver. CPU (Central Processing Unit)

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D

Data communications Downlink (↔Uplink) Transfer of data between two or more locations. Frequency that repeater or satellite transmits on to a user. C dBd DSP ( Processor) D Unit of RF power as compared to a dipole antenna. Used to improve the signal to noise ratio for clearer and more dBi legible communications. Relatively new to the ham radio. Unit of RF power as compared to an isotropic antenna. DTCS (Digital Tone Coded Squelch) dBm A Selective call system Decibels measure, 1 mW with a load impedance of 600 Ω (0 DTMF (Dual Tone Multi-Frequency (=touch-tone)) dBm=1 mW). Used for transmit/receive numeric information such as phone DC () number, PIN, remote radio control commands etc. DC ground Dualwatch A connection point directly to chassis or battery ground to Receiving two signals simultaneously. prevent build-up of hazardous DC voltages. Dummy load Ω Deviation A non radiating 50 load connected to the transmitter to re- A measurement for a FM signals for the maximum carrier fre- place the antenna for testing purposes. quency changes either side of the carrier frequency. Duplex Distress call An operation mode in which the transmit and receive fre- Signals a life-threatening situation. Most commonly referred quencies are different. to as an SOS or call. Duplexer Distress frequency A device which divides transmit and receive signals. A frequency or channel specific for use in distress calling. Ra- Duty cycle diotelephone distress frequencies are 2.182 MHz and 156.8 The ratios of transmit to receive time. MHz. Survival craft use 243 MHz. Maritime distress frequen- Dx’pedition cies are the same, while general aviation frequencies are Trip to foreign land to “be DX.” 121.5 MHz.

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E F

EBS (Emergency Broadcast System) Fading A system where at first an attention tone is transmitted over Signal reduction due to atmospherics. all station ad the second tone followed with specific instruc- Filter tion regarding the receivable frequency in the national emer- A circuit designed to pass only the desired frequency(s). gency. FM EEPROM (Electrically Erasable and Programmable Read Only 1) Memory) 2) FM broadcast EME (Earth-Moon-Earth) FSK (Frequency Shift Keying) Moon bounce communication. FSTV (Fast Scan TV) EMI (Electro-Magnetic Interference) Graphics (and audio) communication using TV broadcast sig- Often called RFI (Radio-Frequency Interference). nals, requires a wide bandwidth. Emission Full duplex Transmission of a signal An operation mode, which transmits and receives on differ- Encryption ent frequencies at the same time, as a telephone communi- Transmitting cryptic form so that only certain people under- cation. stand what has been sent.

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G H

Ground Plane Harmonic A type of Omni-directional antenna Multiple of a fundamental frequency. Ground Wave HF () Electrical wave directly travelling from transmitter. 3–30 MHz range signals. (Normally, 1.9 MHz band also in- cluded.) E Grounding Electrical connection to the earth. HPF (High Pass Filter) F Hz (Hertz) G H

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I L

IC (Integrated Circuit) LF (Low Frequency) 30–300 kHz range signals. IF (Intermediate Frequency) Internally converted frequency for amplification and other sig- Li-Ion (Lithium Ion) nal processing. Rechargeable battery which has better capacity than Ni-Cd, Ni-MH, etc., no memory effect after repeated non-full IF shift charge/discharge cycles. A function that electronically shifts IF frequency from a center frequency. LPF (Low Pass Filter) IMD (Inter-Modulation Distortion) LSB (Lower Side Band) Distortion within RF circuits made with upper and lower adja- cent channel signals.

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M N

MARS (Military Affiliate Radio Service) NB (Noise Blanker) A function reducing pulse-type noises. Memory bank A set of memory channels organized into a group. NBFM (Narrow Band FM) Memory effect Ni-Cd (Nickel-Cadmium) Rechargeable batteries such as Ni-Cd and Ni-MH types may Ni-MH (Nickel-Metal Hydride) be temporality getting less capacity as a result of repeated non-full charge/discharge cycles. It is called so since Notch filter rechargeable batteries lose capacity as if “memorize” wrong Sharp and narrow rejection filter for elimination of interfering full capacity level at less than full charge. Li-Ion batteries are signals free from this effect. NR (Noise Reduction) I MF (Medium Frequency) DSP feature reduces unwanted signal noise 300 kHz–3 MHz range signals L MIC (MICrophone) M Modulation N Method of adding information to a carrier

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O P

Offset frequency PA (Power Amplifier) Frequency difference between transmits and receives. Parawatch (=Dualwatch) OSC (OSCillator) PBT (PassBand Tuning) A function electronically reduce interference by narrowing IF bandwidth PEP (Peak Envelope Power) RF power at maximum amplitude. PLL (Phase Locked Loop) Circuit to synthesize the different frequencies a radio will op- erate on. Pocket beep Beeping function when specific signal is received. Priority watch Reception mode, which by a selected frequency is always pe- riodically, checked when VFO is set to different frequency PTT (Push To Talk) PWR (PoWeR)

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R S

Reflected power S/N (Signal to Noise ratio) Non-radiated power dissipated as heat when the transmitter SAR (Search And Rescue ) is mismatched to the antenna or load. Scan Repeater Continually sweeping frequencies looking for signals. Radio systems, which receive incoming signal and re-trans- mit it for extended communication area. Normally put on ge- Scan Edge ographically high locations for VHF/UHF hand portables. End and start frequencies for a scanning range. RF (Radio Frequency) Scratch Pad Memory Temporary frequency memories for quick access. RF ground Connection of amateur equipment to earth ground to elimi- Semi Duplex nate hazards from RF exposure and reduce RFI. An operation mode in which transmits and receives is ac- complished on different frequencies alternatively. RFI (Radio Frequency Interference) Sensitivity RIT (Receiver Incremental Tuning) Indicates how weak a signal the receiver will pick up. Fine-tuning receive frequency without changing displayed or memory frequency. Set mode An operation mode used for radio. To set less frequently used O RTTY (Radio TeleTYpe) control features. P RX (Receive) Simplex R An operation mode where transmit and receive frequency is same. S Skywarn Trained volunteer storm spotters for the National Weather Service. SMA (Sub-Miniature a connector) Type of antenna connector, used in VHF/UHF portable. SP (SPeaker) 10 Glossary.qxd 02.2.5 18:20 Page 11 (1,1)

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T

Split TCXO (Temperature Compensated Crystal Oscillator) A mode in which the transmit and receive frequency is differ- Heated crystal oscillator for better frequency stability. ent. TNC SQL (SQueLch) 1) Terminal Controller A function muting audio output for set conditions. for . 2) A type of antenna connector SSB (Single Side Band) TOT (Time Out Timer) SSTV (Slow Scan TV) Time limiting function for continued repeater or other opera- Graphics communication using narrow bandwidth. tions. SWL (Short Wave Listener) TS (Tuning Step) SWR (Standing Wave Ratio) Incremental steps Measurement of forward vs. reflected power output during TSQL (Tone SQueLch) transmit. Squelch function using subaudible tones, selective call. TVI (TeleVision Interference) TX (Transmit)

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U V

UHF () VFO (Variable Frequency Oscillator) 300 MHz–3 GHz range signals. An operation mode in which operator can change frequency Uplink (↔Downlink) freely. Frequency that user transmits to the repeater or satellite. VHF () USB (Upper Side Band) 30–300 MHz range signals. UTC (Universal Time Coordinated) VOX (Voice Operated transmission) An astronomical time based on the Greenwich meridian (zero A function automatically put the transmitter in transmit when degrees longitude). talk into a microphone. VSC 1) Voice Scan Control 2) Voice Squelch Control

S T U V

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W Number/Others

Weather Alert NOAA broadcast station transmitting alert signals. WFM (Wideband FM)

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W

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