ANTENTOP- 02- 2010, # 014

Grounded and Underground Antennas

Chapter from the book: Alpert, Bulatov, Runge: Antennas of the Third Reich: Published by Ministry of Defense of the USSR, Moscow, 1948. (Circulation: 300 copies). Credit line: http://www.radioscanner.ru/files/antennas/file10355/

Figure 131 shows that the closer a horizontal antenna to the ground the more horizontal component at Electro- Magnetic Radiation of the antenna. However the closer an antenna is to the ground the less efficiency of the antenna.

Efficiency is lowered because of the losses in the ground and in the antenna wire. The losses rise dramatically with increasing of the working frequency of the antenna.

Figure 131 Changing the Front of a Radio-wave near the Ground

Figure 145 shows experimental data of the (antenna) gain by the ground wave for TWA of the 150 meter length of wire hanged at 2.8-meteres above the ground and Grounded Antenna - Insulated Wire in 150- meter length sitting on the ground. If the Grounded Antenna would be made from a naked wire the antenna dramatically decreased (compare to grounded antenna from the Figure 145).

Installation of the ground antenna is much easer the TWA. However, a ground antenna is much easer to damage compare to TWA. It is happened by moving vehicles. TWA is usually hang up at a height 2.8- 3 meter to avoid the damage by the vehicles.

Sometimes for grounded antennas is used a usual horizontal dipole antenna located straight over the ground.

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