The gateway exchange is the center at which the international exchange multiplex equipment and ancillary equipment, for international telephone and/or telegraph, Telex data, Television and Facsimile are located.
Radio signals are transmitted through electromagnetic waves, also called radio waves, in radio communication system. The radio waves have a wide frequency range starting from a few ten kilo Hertz (kHz) to several thousand Mega Hertz (MHz).
As shown in the given diagram the half wave length transmission line can be open circuited or short circuited. The length of the transmission line is valid only for the particular frequency at which λ/2 of that transmission line is calculated other than that frequency. Read more about Half & Quarter Wave Length Transmission Lines
Transmission line is defined as the path of carrying alternating electrical energy from source to load. For example the wire used between T.V antenna and television set or the wire used between transmitter antenna and transmitter are known as transmission