| 摘要 |
The invention relates to a logarithmic, periodical antenna array with dipoles of varying length attached to a boom, surrounding feeders in contact with the radiator elements of the dipoles. The antenna preferably has adjustable operating direction. In order to enable the use of the antenna for two different frequency ranges, each half-wave dipole has a central portion protruding from the boom and surrounded by two tubular collinear members separated by a gap. The inner member is only secured to the boom, and the outer member only to the end of the arm. Free outside and along it, at least one of the tubular members has a metal member, only attached to the end of the tube at the gap. In the lower frequency range the current distribution half-wave reaches between the outer tubular members in each dipole pair, and in the higher frequency range the outside metal members will give one current distribution half-wave over each radiator element in a dipole pair.
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