Antenna terms, and definitions

T-Antenna: A wire antenna in the shape of a 'T'.

Test Antenna: An antenna of known performance characteristics used in determining transmission characteristics of equipment and associated propagation paths.

Take-off angle: The angle measured from the surface of the earth or horizontal up to the direction of propagation towards the ionosphere. The angle [see graphic] above the horizon that an antenna radiates the greatest amount of energy.

Three-Element Array: An array with two parasitic elements (reflector and director) and a driven element.

Top-Hat: An antenna that is center-fed and capacitively loaded.

Towed Dish: Towed antenna, An antenna that is towed behind another vehicle, as shown in the graphic. An antenna that has no fixed location. A similar graphic to the trailer mounted Dish is a Humvee Mounted Dish Antenna, same antenna on a different mount [see Dish Antenna]. A movable, fixed antenna. A related term is Mobile Antenna.

Towed Dish Antenna

Tower: A Mast. See Antenna Tower.

Tracking Antenna: An antenna that can be made directional, or automatically follow a moving target. An antenna which moves the position of its major lobe so that a selected moving target is contained within the major lobe.

Transistor: A minute electronic device that permits a small current to control the flow of a larger current. Also refer to the General Engineering Dictionary, or listing of Transistor Manufacturers.

Transmission line: A conductor that transfers radio frequency RF energy from the transmitter to the antenna or from the antenna to the receiver.

Transmittance: The ratio of the transmitted power to the incident power.

Transmitter: A piece of equipment that generates and amplifies a radio frequency, adds intelligence to this signal, and then sends it out into the air as a radio frequency wave.

Transmitting Antenna: The device used to send the transmitted signal energy into space.

Triatic: A special type of monopole antenna array.

Troposphere: The region of the Earths atmosphere from the surface to a height of about 10 km.

Truncated Paraboloid: A paraboloid reflector [antenna] that has been cut away at the top and bottom to increase beam width in the vertical plane.

Tuned Antenna. Text in review.

Tuned Dipole. A dipole antenna that resonates at its operating frequency.

Tuning: The process of adjusting a radio circuit so that it resonates at the desired frequency.

Turnstile Antenna: A type of antenna used in vhf communications that is omni-directional and consists of two horizontal half-wave antennas [dipole antenna] mounted at right angles to each other in the same horizontal plane.

Twin-lead transmission line: A balanced transmission line generally used with balanced antennas.

Twin Whip Antenna: A pair of whip antennas that are connected together when they are closer than 25 feet from each other. A pair of whip antenna's driven by the same source is shown in the diagram to the right.

Two element array: An antenna composed of two element antennas.