T-antenna
![Multiwire T broadcast antenna of early AM station WBZ, Springfield, Massachusetts, 1925](/Images/godic/202502/15/Wire_T_antenna_station_WBZ_19255617.jpg")
![Types of T antennas: (a) simple (b) multiwire. Red parts are insulators, grey are supporting towers.](/Images/godic/202502/15/T_antenna.svg5617.png")
![RF current distributions (red) in a vertical antenna (a) and the T antenna (b), showing how the horizontal wire serves to improve the efficiency of the vertical radiating wire.[6] The width of the red area perpendicular to the wire at any point is proportional to the current. At resonance the current is the tail part of a sinusoidal standing wave. In the vertical antenna, the current must go to zero at the top. In the T, the current flows into the horizontal wire, increasing the current in the top part of the vertical wire. The radiation resistance and thus the radiated power in each, is proportional to the square of the area of the vertical part of the current distribution.](/Images/godic/202502/15/T_antenna_vs_vertical_antenna.svg5617.png")
![One of the first uses of T-aerials in the early 20th century was on ships, since they could be strung between masts. This is the antenna of the RMS Titanic, which broadcast the rescue call during her sinking in 1912. It was a multiwire T with a 50 m vertical wire and four 120 m horizontal wires.](/Images/godic/202502/15/Titanic_antenne_T_015617.JPG")
A T-antenna, T-aerial, flat-top antenna, or top-hat antenna is a vertically polarised simple wire radio antenna used in the VLF, LF, MF and shortwave bands. T-antennas are widely used as transmitting antennas for amateur radio stations, long wave and medium wave broadcasting stations. They are also used as receiving antennas for shortwave listening.