Multiband dipole. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / HF antennas
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Finnish radio amateur Pekka Pyukko (OH1NE) from Turku sent a description of his multi-band dipole designed to operate in the 3,5 bands; 7; fourteen; 14 and 21 MHz. According to the author of the letter, the dipole gives good results at 29; 3,5; 7 and 14 MHz (with low standing wave ratio). Sufficiently good results and a low standing wave ratio were obtained at 29 MHz.
The dipole of the radio amateur OH1NE is shown schematically in fig. one.
The length of each of the arms is equal to a quarter wave of the 3,5 MHz band (that is, 2 * l / 4 \u2d 20,6 * 300 m). The matching transformer is made from a two-wire 17,6-ohm line and has a length of XNUMX m if the length of the feeder exceeds the length of the matching transformer (the feeder for this antenna can be of any length). The lower end of the matching transformer, as shown in the figure, is open.
The stub of the matching transformer can be left hanging freely, hung under the feeder (but not too close) and finally they can be twisted together (but not too tight).
Author: Pekka Piukko (OH1NE); Publication: N. Bolshakov, rf.atnn.ru
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