| 摘要 |
PURPOSE:To mount a nondirectional auxiliary antenna to one support without giving any effect onto other antenna by arranging a direction finding antenna to the upper side of the midpoint of the support and arranging a sectorial dipole antenna to the midpoint of the lower support. CONSTITUTION:The sectorial antenna is arranged to the midpoint of the support lower than the position arranged with direction finding antennas 4, 5, 6 to form nondirectional lower/middle frequency band auxiliary antenna 7. Then, the interval of the parallel part between the antenna element 7A and the support 1A is set in a range of 1/10-1/40 of the wavelength of the highest frequency of the law/middle frequency hand shared by the antenna 7 as near as possible. Moreover, the upper end of the antenna element 7A is arranged with a distance to a degree not interfered with the lower end of the direction finding antenna element 6A at the upper side. Thus, no disturbance error takes place or no dead frequency band is caused due to the radio wave of the middle/lower frequency band.
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