Also found in: Wikipedia.
turnstile antenna[′tərn‚stīl an‚ten·ə]
a complex multiple-section antenna, each section of which consists of a crossed pair of horizontal and symmetrical half-wave dipoles that are normal to each other and fastened to a common vertical mast. The number of sections in a turnstile antenna usually ranges from one to several tens. The dipoles of each pair are energized so that the currents in the two dipoles are equal but out of phase by 90°. Such energizing results in a nearly circular radiation pattern in the horizontal plane.
Turnstile antennas are used in television and in radio broad casting, mainly as transmitting antennas in the meter wavelength range. In television, turnstile antennas with broadband dipoles shaped like two K’s drawn back to back are often used (see: Figure 10).