Dual band VHF antenna. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / VHF antennas
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After 10 years of experimentation, I came to the conclusion that the construction of omnidirectional antennas on the HF bands is impractical, primarily because of poor reception.
The absence of scarce aluminum pipes prompted the idea to make a modification of the PA0LU wire antenna at 14 MHz [1]. The essence of the revision is that instead of straight dipoles, bent dipoles are used (Fig. 1), and the middle points of the dipoles are fixed on a traverse, which is welded to a pipe segment installed in the mast on a plain bearing (Fig. 2).
Ris.1
Antenna tuning is the same as in [1]. To turn the antenna, nylon braces are removed that fasten the ends of the vibrator and director, then (manually or electrically) the traverse is unfolded, after which the ends of the elements are fixed in a new position by braces.
Ris.2
Similarly, you can make a three-element antenna. On this antenna (14 MHz), when operating CW and power 40 W, contacts were made with CX, LU, USA, JA.
Accordingly, by increasing the size, the antenna can also be used on the low-frequency ranges.
Literature
1. K. Rothammel. Antennas. Translated from German, 3rd ed., add. - M.: Energy, 1979, pp. 81-83.
Author: V.Chernomorov (UA1ZFC); Publication: N. Bolshakov, rf.atnn.ru
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