31. RDF systems using mechanically swung loop or dipole antennas were common by the turn of the 20th century. 32. Several types of balun are commonly used to feed a dipole antenna : current baluns and coax baluns. 33. Twin-lead also can serve as a convenient material with which to build a simple folded dipole antenna . 34. Simple half-wave dipole antenna for VHF or UHF loop antennas that are made to be placed receiver. 35. The earliest research in metamaterial antennas was an analytical study of a miniature dipole antenna surrounded with a metamaterial. 36. Four dipole antennas were mounted on orthogonal arms, and the shelter and antennas rotated to scan in azimuth. 37. According to half-wavelength dipole antenna for signals in the range of 50 m wavelength, about 6 MHz. 38. Adcock & mdash; who was serving as an Army officer in the monopole or dipole antennas of equal length. 39. In 2009, the Millennium Transmitter increased its height to 720 feet and was also reinforced with powerful dipole antennas . 40. The NASA rectenna was made of a thin plastic film, with dipole antennas and receiving circuits embedded in its surface.
