FLAT LINEA transmission line that has no standing waves. This line requires no special tuning
device to transfer maximum power.
FLEXIBLE COAXIAL LINEA coaxial line made with a flexible inner conductor insulated from the
outer conductor by a solid, continuous insulating material.
FOLDED DIPOLEAn ordinary half-wave antenna (dipole) that has one or more additional conductors
connected across the ends parallel to each other.
FOUR-ELEMENT ARRAYAn array with three parasitic elements and one driven element.
FREE-SPACE LOSSThe loss of energy of a radio wave because of the spreading of the wavefront as
it travels from the transmitter.
FREQUENCYThe number of cycles that occur in one second. Usually expressed in hertz.
FREQUENCY DIVERSITYTransmitting (and receiving) of radio waves on two different frequencies
FRONT-TO-BACK RATIOThe ratio of the energy radiated in the principal direction to the energy
radiated in the opposite direction.
FUNDAMENTAL FREQUENCYThe basic frequency or first harmonic frequency.
GAINThe ratio between the amount of energy propagated from an antenna that is directional to the
energy from the same antenna that would be propagated if the antenna were not directional.
GENERATOR ENDSee INPUT END.
GROUND PLANEThe portion of a groundplane antenna that acts as ground.
GROUND-PLANE ANTENNAA type of antenna that uses a ground plane as a simulated ground to
produce low-angle radiation.
GROUND REFLECTION LOSSThe loss of rf energy each time a radio wave is reflected from the
GROUND SCREENA series of conductors buried below the surface of the earth and arranged in a
radial pattern. Used to reduce losses in the ground.
GROUND WAVESRadio waves that travel near the surface of the Earth.
HALF-WAVE DIPOLE ANTENNAAn antenna consisting of two rods (1/4 wavelength each) in a
straight line, that radiates electromagnetic energy.
HARMONICA frequency that is a whole number multiple of a smaller base frequency.
HERTZ ANTENNAA half-wave antenna installed some distance above ground and positioned either
vertically or horizontally.
HORIZONTAL AXISOn a graph, the straight line axis plotted from left to right.
HORIZONTAL PATTERNThe part of a radiation pattern that is radiated in all directions along the