Experimental Fast-Wave Dual Dipole VLF Transmitting Antenna.
NAVAL WEAPONS CENTER CHINA LAKE CA
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An 11-mi long dual-dipole horizontal VLF transmitting antenna has been constructed on the lava beds of Hawaii. Measurements show that the antenna has a broad bandwidth 20 at several self-resonant points in the VLF band, and that the radiation efficiency is proportional to the number of dipoles used. Also, the cost is less than 1 of the cost of equally efficient vertical VLF transmitting antennas now being used by the Navy. The radiation efficiency of the horizontal dipole is increased by using series capacitors to increase the wave velocity along the antenna. The value of capacitors used 0.12 microfarads1500 ft optimizes the wave velocity at 20 kHz. The efficiencies shown at other frequencies can be increased by using the optimum value of series capacitance. Environmental conditions such as rainfall have very little effect on the antenna performance. Author
- Electrical and Electronic Equipment