Multirange symmetrical dipole. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / HF antennas
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On the radio station RB4IX for operation in the ranges of 1,9 ... 14 MHz, a dipole with a shoulder length of 41,5 m is used, powered by a symmetrical R-300 Ohm line. However, when the power line is directly connected to the transceiver, the transforming properties of the P-loop are not enough.
To ensure the adjustment of the P-loop between the power line and TRX, a simple matching device is used, consisting of a variometer and a 1:4 SHPT (Fig. 1). A coil with a diameter of 50 mm contains 63 turns of wire with a diameter of 1 mm.
Approximate number of turns in the ranges: 1,9 MHz - 63; 3,5 MHz - 30; 7 MHz - 20; 14MHz-5.
Ris.1
The setting consists in selecting the number of turns of the coil according to the maximum glow of all four neon lamps. The electrical circuit of the SPT is shown in Fig.2.
Ris.2
ShPT is wound in three wires of 10 turns (stranded, tinned) on a package of five rings 2000 NM with a diameter of 50-60 mm. The wiring diagram of the SPT is shown in Fig.3.
Ris.3
Comparative tests have shown that on the low bands this antenna is practically not inferior to a full-sized triangle at 80 m. TVI is absolutely absent on all bands when the RA is operated on three GU50 with grounded grids.
Author: V.Naidovsky, (RB4IX), Donetsk; Publication: N. Bolshakov, rf.atnn.ru
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