A simple tri-band antenna. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / HF antennas
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During the year, my radio station of the second category has been operating a simple antenna (see Fig. 1), which is a modification of the DL1BU antenna. It operates on 40, 20 and 10 m, does not require the use of a symmetrical feeder, is well matched, and easy to manufacture.
Ris.1
As a matching balancing element, a transformer was used on a ferrite ring of the VCh-50 brand with a cross section of 2,0 cm2. The number of turns of the primary winding is 15, the secondary is 30, the wire is PEV-2 with a diameter of 1 mm.
When using a ring of a different section, it is necessary to re-select the number of turns using the diagram shown in fig. 2. As a result of the selection, it is necessary to obtain a minimum SWR in the range of 10 m.
Ris.2
The antenna made by the author has an SWR of 1,1 at 40 m, 1,3 at 20 m and 1,8 at 10 m.
Author: V. Kononov (UY5VI) Donetsk; Publication: N. Bolshakov, rf.atnn.ru
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