A novel log-periodic monopole array

In a long-distance HF communication system, the operating frequency requires frequent change to accommodate variations of heights of ionosphere layers. Such frequency switching also calls for antenna switching. Because of its extremely broadband characteristics, a log-periodic antenna or array is especially useful in HF communication, as the HF band, 3-30 MC, can be easily covered with a single antenna of this kind, and the antenna switching is eliminated.