Dictionary of Ham Radio Terms

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A

Amplitude : the height of a wave from the average or median position.

B

Band : the portions of the Electromagnetic Spectrum that are allocated to ham radio operators

C

Coaxial Cable : Cable that has a central conductor and an outer shield as the second conductor. Known as coaxial because the cable is cylindrical and the conductors share the same central axis.

D

Dipole : An antenna with two sides, usually of equal length.

Dish : A highly directional antenna, parabolic in shape. Often used at microwave frequencies.

E

Electromagnetic Waves : The waves emmitted by an antenna, having two dimensions, electric and magnetic.

F

Feedline : The wire of cable that jouns a transmitter or receiver to an antenna

Frequency: the number of complete waves that pass a reference point per second. Expressed in Hertz (Hz)

G

Gain : How much more effective an antenna is as a radiator than a half wave dipole

H

HF : High Frequency. Frequencies in the range 3MHz to 30MHz

L

LPDA : Log Periodic Dipole Array. A multiband Antenna

O

OCF : Off Centre Fed Dipole. A dipole that has sides of unequal length. These are multiband wire antennas

P

Period : the time it taks in seconds for a complete wave to pass a reference point.

S

SWR : Standing Wave Ratio. The ration of the height of a standing wave on a transmission line to the height of an adjacent node.

T

Transmission Line : Also known as feedline.

U

UHF : Ultra High Frequency. Frequencies in the range 300MHz to 3 000MHz

V

VHF : Very High Frequency. Frequencies in the range 30MHz to 300MHz

W

Wavelength : the distance in metres between corresponding points on a wave.

Numbers

73 : Goodbye