| 摘要 |
PURPOSE:To improve the electrical characteristic of an antenna, by mounting a vessel- shaped cover in such a way that it can be axis-driven so as to enclose a primary radiator, and fixing plural fins provided in a direction inclined for an axis on the circumferential plane of the cover and a weight to rotate and restore the cover to its initial position, respectively to effectively prevent snow from being laid. CONSTITUTION:The primary radiator 1 is arranged at a position off set for a reflecting mirror 2, and the primary radiator 1 is covered with the cover 3. Also, the aperture end part formed thinly of the cover 3 is coupled with the primary radiator with a bearing 6, and a device is constituted so that the cover 3 can be easily rotated setting the direction of the radiation of the wave of the primary radiator 1 as a center axis. Also, on the circumferential plane of the cover 3, the plural fins 4 are provided in spiral direction. Also, the weight 5 with appropriate weight is fixed at a part of the circumference of the cover 3. In such a way, the snow 7 is not laid symmetrically in a horizontal direction for a Y-axis, and is laid unbalancingly. Therefore, the cover 3 is rotated in a direction of arrow head A due to the weight of the snow. Thereby, the snow drops as soon as it is laid on the cover 3, then, the snow can be prevented from being laid on the cover 3.
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