Antenna for the range of 160 meters with a low suspension height. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / HF antennas

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The described antenna can be useful for use in cities with dense buildings. It is a wire frame with a perimeter of two wavelengths. The proposed placement of the antenna is shown in Fig.1.

Since the directions of the current of the opposite ends of the loop are in antiphase, spurious upward radiation is significantly reduced. The radiation pattern in the vertical plane is shown in Fig. 2, and in the horizontal plane it does not have pronounced maxima and can be considered circular.

The bandwidth of the antenna is about 100 kHz in terms of SWR=2. The input impedance is 160 Ohm at a suspension height of 30 meters (typical 9-storey buildings) and decreases as the suspension height decreases. The calculated data for other suspension heights at a resonant frequency of 1,85 MHz are given in Table. 1.

Table 1

With a suspension height of 20 m to 50 m, the maximum radiation angle to the horizon in the radiation pattern changes slightly - from 48 to 40 degrees, respectively. The antenna was simulated and tested in the 2 m range and confirmed the calculated performance.

Author: Nikolay Fedoseev, UT2UZ, Kiev; Publication: N. Bolshakov, rf.atnn.ru

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