LOWEST USABLE FREQUENCYThe minimum operating frequency that can be used for
communications between two points.
LUMPED CONSTANTSThe properties of inductance, capacitance, and resistance in a transmission
LUMPED-IMPEDANCE TUNINGThe insertion of an inductor or capacitor in series with an antenna
to lengthen or shorten the antenna electrically.
MAGNETIC (H) FIELDThe field produced when current flows through a conductor or antenna.
MAJOR LOBEThe lobe in which the greatest amount of radiation occurs.
MARCONI ANTENNAA quarter-wave antenna oriented perpendicular to the earth and operated with
one end grounded.
MAXIMUM USABLE FREQUENCY Maximum frequency that can be used for communications
between two locations for a given time of day and a given angle of incidence.
MEDIUMThe substance through which a wave travels from one point to the next. Air, water, wood,
etc., are examples of a medium.
MINOR LOBEThe lobe in which the radiation intensity is less than a major lobe.
MULTIELEMENT ARRAYAn array consisting of one or more arrays and classified as to directivity.
MULTIELEMENT PARASITIC ARRAY An array that contains two or more parasitic elements and
a driven element.
MULTIPATHThe multiple paths a radio wave may follow between transmitter and receiver.
NATURAL HORIZONThe line-of-sight horizon.
NEGATIVE ALTERNATIONThe portion of a sine wave below the reference line.
NODEThe fixed minimum points of voltage or current on a standing wave or antenna.
NOISE (OF SOUND)An unwanted disturbance caused by spurious waves that originate from man-
made or natural sources.
NONLUMINOUS BODIESObjects that either reflect or diffuse light that falls upon them.
NONRESONANT LINEA transmission line that has no standing waves of current or voltage.
NORMALThe imaginary line perpendicular to the point at which the incident wave strikes the
reflecting surface. Also called the perpendicular.
NULLOn a polar-coordinate graph, the area that represents minimum or 0 radiation.
OMNIDIRECTIONALTransmitting in all directions.
OPAQUEA type of substance that does not transmit any light rays.
OPEN-ENDED LINEA transmission line that has an infinitely large terminating impedance.