end-fire gain, end-fire techniques telecom.

[GL]

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Highly reliable communications on long-range circuits require antennas with high power gain at low take-off angles. In addition, ionospheric variations resulting in frequent changes in frequency make it desirable for the antenna to have a wide frequency bandwidth. The conventional approach to achieve wide band, highly directive antennas has been to use multiple rhombic antennas which rely heavily on end-fire gain to achieve their directivity and hence are quite large. Typical installations exceed 300 meters in length and require large investments in land. Log-periodic antennas have long been desired for their wide band characteristics, efficient land use, and modest price. Heretofore, increasing the gain of a log-periodic has been attempted through end-fire techniques. This approach results in very large structures which are difficult to support and install.

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