Efficient DX Antenna. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / HF antennas
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JA7RKB offers an efficient 2x3/4 Inv.V DX antenna (Figure 1).
Ris.1
With such an arrangement of the antenna web, when the centers of the extreme half-wave sections are at a distance of half a wavelength, their radiation fields are added. The quarter-wave sections of the canvas, located at the top of the antenna, have practically no effect on the radiation pattern.
Ris.2
Figure 2 shows the dimensions of the antenna for an average operating frequency of 29,2 MHz, and Figure 3 shows the frequency dependence of its SWR.
Ris.3
According to JA7RKB and his DX correspondents, this vertically polarized antenna radiates at very small angles to the horizon and on long paths is 2-3 points more efficient than a conventional half-wave dipole.
Author: JA7RKB; Publication: N. Bolshakov, rf.atnn.ru
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Adrian Melott (Adrian Melott) from the University of Kansas at Lawrence (USA) and his colleague Brian Thomas (Brian Thomas) from Washburn University in Topeka (USA) studied the "superflare" on the Sun in the 774th century AD, whose traces were recently found in annual rings of Japanese cedars. A solar superflare in 1859 turned out to be several times more powerful than the previous record holder, the "Carrington event" of XNUMX, capable of destroying all electronic devices and electrical networks on Earth, astronomers say in an article posted in the electronic library of Cornell University.
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