Field experiments were performed on a medium-wave broadcasting antenna located on a mountain top. The input impedance and field strength of two different length monopole antennas located on top of a conical shaped model mountain with a height of 3. 75 m were measured and compared with those of two monopole antennas located at ground level and a frequency range of 10 MHz to 50 MHz. The mountain was constructed out of clay on a flat surface. The lengths of the monopole antennas were 3. 75 m and 1. 87 m which corresponds to a quarter wavelength antenna at 20 MHz and 40 MHz, respectively. The field strength of the quarter wavelength antennas was observed to be about 0. 5 db to 4. 5 db at 20 MHz and 2 db to 6 db at 40 MHz greater than that of antennas located at ground level. These results indicate the antennas on a mountain top have improved gain when compared with antennas located at ground level.
|ジャーナル||Terebijon Gakkaishi/Journal of the Institute of Television Engineers of Japan|
|出版物ステータス||Published - 1987 1 1|
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