| 摘要 |
Antennas are an indispensable part of every radio transmitting and receiving system. There are therefore a multiplicity of designs, which all have advantages and disadvantages. The invention relates to antennas in the short-wave band and here, in particular, to multi-element designs which can rotate. The advantages of such systems in radio terms are known. However, it is difficult to produce such designs easily and nevertheless robustly. The elements of such antenna systems are in addition frequently interrupted by coils or blocking circuits, which likewise increases the risk of fracture. Aluminium tubing is used virtually exclusively as the material for these designs. Although the tubes become more robust with greater diameters, they are, however, heavier and more expensive. Glass-fibre-reinforced plastic tubing is offered as an alternative. The mechanical properties of this material are excellent and the weight is considerably lower. Since this material is also a very good insulator, an antenna element consisting of such material does not need to be interrupted at the points of coils or blocking circuits. The problem in the case of this material is the actual antenna conductor. A wire could be inserted for this purpose. However, as a consequence of its high slenderness ratio this gives the antenna a very narrowband nature, which is undesirable in the case of most antennas. In addition, the wire must be fixed centrally in the tubing since, in the event of a change in the distance from the wall, the tuning of the antenna ... Original abstract incomplete.
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