ΓΛΩΣΣΑΡΙ

ΘΕΩΡΙΑ 2

ΓΛΩΣΣΑΡΙ

Active — A device or circuit that requires a supply voltage to operate.

AGC — Automatic Gain Control

ARRL — American Radio Relay League. The USA amateur radio society.

Amateur Radio — The great following that allows international and local communication by transmitting and receiving radio signals.

Amateur satellites — Satellites that service amateur stations.

Ampere (A)— The unit of current measurement.

Atom — An assembly of protons, electrons, and neutrons making up the smallest particle of an element.

Balun — An abbreviation of—Balanced to unbalanced.

Bandpass — A circuit that allows a single band of frequencies to pass but not allowing frequencies above and below the single band of frequencies to pass.

Bandwidth (BW) — The frequency width of a circuit, usually measured between the half-power or -3 dB points.

Break-In — The monthly magazine produced by The New Zealand Association of Radio Transmitters Inc.

Bridge — To place one component in parallel with another, or to electrically join components or conductors. Also a measuring instrument that compares values by ratios.

Callbook — An annual NZART publication that lists all New Zealand and Pacific Island amateurs. The book also contains valuable reference information important to amateurs.

Chip (IC) — A common term used to describe integrated circuits. Also used to describe devices that have special construction features.

Clamp — To hold a voltage waveform at a predetermined level.

Converter — A circuit used in receivers to convert one frequency to another by mixing it with a third frequency—also called a mixer. Also used for conversion of a DC voltage to a higher value.

Common— Common point for radio circuits (same as ground, return, and earth).

Communication — The exchange of information.

Core — A magnetic material that is the centre piece of a transformer or inductor.

Damped or damping — A progressive decrease in amplitude.

Decay — The decrease in a quantity to a predetermined value usually measured in time units.

Decibel (dB)— A logarithmic measurement of values that corresponds to the response of the ear. Decibels convert large values to understandable values.

Digital — Signals that have two levels—on and off is an example.

Dip oscillator — A meter that shows the frequency of a resonant circuit by a dip in its meter reading.

Discrete — Not in an integrated circuit form.

Drift — A gradual change from the desired effect.

Drive — In transmitters it is the output signal from the previous stage to the input of the next stage.

Dummy load — A device that is connected to the antenna output of a transmitter which can absorb the full RF output power of the transmitter.

Duplex — Uses two frequencies for transmission and reception.

Duplexer — Used as a combining device for amateur repeater antenna, so that the repeater's transmitter and receiver can use one common antenna.

DX — Amateur radio expression for "long distance".

Dynamic range — The range over which a device can produce useful results.

Earth — Common point for radio circuits (same as ground, return, and common).

Electrons— The smallest part of any atom.

Electronics — The technology of conduction of an electric current in a vacuum, gas, or semiconductor.

Examination — A test for an Amateur Radio operators' certificate, thus allowing the operation of radio transmitting equipment.

Excitation — Another name for drive.

Feedback — Output signal fed back to the input to alter the input signal.

Ferromagnetic — Iron magnetic material.

Finite — Has an end.

Gate — A circuit that allows signals to pass when permitted by another similar signal of an independent source.

Ground — Common point for radio circuits (same as earth, return, and common).

Ground plane — Used in antennas as an artificial earth surface.

Ground wave — A wave that is propagated along the surface of the earth.

Half-power point (-3 dB point) — A point that is used to measure bandwidth. It is measured at the -3 dB power points or 0.707 of the voltage points.

HAMS — Term used generally for Amateur Radio operators.

High current — Usually when currents are over 1 ampere.

High fidelity (Hi-Fi) — The range of audio frequencies from below 100 Hz to above 20 kHz.

High frequency (HF) — The amateur bands between 3 MHz and 30 MHz.

High gain — Usually obtained at greater cost than the normal or standard gain circuits or devices.

High power gain — A device that has both a high voltage and a high current gain.

High grade — Pure—similar to high purity.

High impedance — Normally values over 1 MΩ.

High losses — Heating of components or other abnormal effects occurs.

High permeability — Magnetic core multiplying factors of over 10.

High power — Values over 10 watts.

High purity — Pure—similar to high grade.

High Q — Quality factor value of a tuned circuit over 100.

High reactance — Values greater than 100 kΩ.

High resistance — Values over 1 MΩ

High stability — Tolerances less than 1%.

High value — Values over 1 MΩ.

High voltage — Values over 100 V.

High-pass — Passes all frequencies over a specified frequency.

IARU — The International Amateur Radio Union (the world-wide union of amateur radio societies).

IC — An abbreviation for integrated circuit.

Integrated circuit (IC) — An electronic package that contains many electronic devices.

International Radio Regulations — Regulations from the International Telecommunication Union (ITU).

ISM — Industrial, Scientific, and Medical.

ITU — the International Telecommunication Union (the source of the International Radio Regulations).

Leakage — An unwanted current flow because of imperfect materials.

Licensing — A requirement for Amateur Radio operators because of their ability to transmit RF signals world-wide.

Linear — The output signal is the same wave-shape as the input signal but the output signal is greater in amplitude.

Load — The device where an output, such as a transmitter's RF output power, or a power supplies' DC output power, is used for useful purposes.

Long distance (DX) — Usually means overseas or can be out of line-of-sight range.

Long wire — When the length of the antenna is greater than a half-wave length long.

Low frequency (LF)— Frequencies less than 300 kHz.

Low impedance — Less than 1 kΩ.

Low level — Powers in the milliwatts and microwatts ranges. Also voltages and currents in the microvolt and microamp range.

Low-pass — Passes all frequencies below a specified frequency.

Mean value — An average value.

Microwaves — Frequencies over 1 GHz.

Ministry of Economic Development, Radio Spectrum Management Group — The New Zealand administration and radio licensing authority.

Mixer — Has two input frequencies and two output frequencies. The output frequencies are the sum and the difference of the input frequencies.

Mode — In radio, it refers to choice of phone (AM, SSB, FM etc.), Morse code (CW), Digital (PSK31 etc.)

Modulation — Placing information on RF waves.

Morse code — An on-off code developed by Samuel Morse in 1837.

Narrowband — Less than 1 kHz bandwidth.

Network — A group of components connected to form a circuit.

Noise bridge — A radio frequency bridge using a radio frequency noise source to measure and indicate antenna resonance and impedance.

NZART (The New Zealand Association of Radio Transmitters Incorporated) — The group that looks after Amateur Radio interests in New Zealand.

Parameters — The characteristics of a device.

Parasitics — Unwanted signal.

Passive device — A device or circuit that does not require a supply voltage to operate.

PEP (Peak envelope power) — A measurement of transmitted power when using SSB modulation.

Permeability — The ability of a magnetic material used as a core in an inductor, to increase the magnetic properties of an inductor compared with no core being present.

Phase locked loop (PLL) — A combination of circuits used to generate variable stable RF signals—usually for the VFO in amateur receivers and transmitters.

Radio shack — The place where the Amateur Radio operator operates!.

Repeater — A transmitter and receiver arranged to receive and retransmit amateur signals.

Resonator — Usually a coil or tuned circuit.

Return — Common point for radio circuits (same as earth, ground, and common).

Ripple — The unwanted component resulting from rectification of an AC wave.

Rise time — The time taken for a current or voltage to rise to a predetermined value.

RMS (Root-mean-square) — The equivalent heating value of an AC wave when compared to a DC value.

Saturation — Occurs when any increase in input signal causes no increase in output signal.

Shunt — Placed in parallel with the component or device (see Bridge).

Silicon chip (IC) — A common term used to describe integrated circuits (see chip).

Solenoid — A coil of wire wound on a cylindrical former.

Standing wave ratio (SWR) — The ratio of the maximum power to the minimum power measured on a transmission line when the load at the end of the transmission line does not absorb all the power supplied by the transmitter.

Syllabus — The guide to the contents of the Amateur Radio Examination.

Tank — Usually the last tuned circuit in a radio transmitter.

Toroid — A magnetic core that is formed into a loop.

Transceiver — A piece of amateur equipment containing both the transmitter and receiver in one cabinet.

Transformer — A device with two or more windings on a magnetic core.

Transmission line — The line between the transmitting equipment and the antenna.

Transmitting equipment — Equipment that is capable of generating and transmitting an RF signal.

Transverter — Usually an external device to extend the frequency range of a receiver or transmitter.

Trap — A tuned circuit that can be adjusted to remove unwanted frequencies.

Ultra high frequency (UHF) — The range of frequencies between 300 MHz and 3000 MHz.

VCO (Voltage controlled oscillator) — Part of a phased locked loop (PLL).

Very high frequency (VHF) — The range of frequencies between 30 MHz and 300 MHz.

VSWR (Voltage standing wave ratio) — The ratio of the maximum voltage to the minimum voltage measured on a transmission line when the load at the end of the transmission line does not absorb all the power supplied by the transmitter.

Wave — The RF wave that radiates from an antenna.

Wavelength (l) — The distance measured between two similar points on consecutive cycles of the RF wave radiated from an antenna.

Wideband — Bandwidths greater than 3 kHz.

X — The symbol used for reactance.

Yagi — A beam antenna.

Z — The symbol used for impedance.

Zener diode — A voltage regulator diode.

SUPER ELECTRONICS GR