Antenna for operation on the range of 160 meters. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / HF antennas
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On fig. Figure 1 shows the antenna I use on 160m. It consists of a tilted radiator A and three counterweights a, b, c, stretched parallel to the ground.
Fig. 1
The antenna is fed with an unbalanced coaxial cable with a characteristic impedance of 75 ohms. The central conductor is connected to a variable capacitor C1 (Fig. 2) of a matching device, which is placed in a moisture-proof box.
Fig. 2
An SWR meter is required to tune the antenna. First, all counterweights must be disabled. Then, a feeder with a characteristic impedance of 75 ohms is connected to two of them, for example a and c, and, having connected to the transmitter, the SWR is determined in the middle and at the edges of the range. If the SWR is high, then it is necessary to adjust the counterweights by changing their geometric dimensions. A similar operation is performed with the third counterweight, having previously turned off any of the previous ones. After adjusting all counterweights, they are connected to the cable sheath and the inclined emitter is adjusted. By changing the capacitance of a variable capacitor, a minimum SWR value is achieved in the middle of the range.
In the author's version, the SWR of the antenna in the middle of the range was equal to 1.3, at the edges of the range - no more than 1.6.
Author: V. Starostin (UA3PFC), Tula; Publication: N. Bolshakov, rf.atnn.ru
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