• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Electrical Engineers - Part III: Radio and Communication Engineering, Journal of the Institution of >The Use of Earth Mats to Reduce the Polarization Error of U-Type Adcock Direction-Finders
【24h】

The Use of Earth Mats to Reduce the Polarization Error of U-Type Adcock Direction-Finders

机译：使用地垫来减少U型Adcock测向仪的极化误差

获取原文
获取原文并翻译 | 示例
       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The paper deals with the experiments carried out in 1943?44 to investigate the use of an earth screen or mat to reduce the polarization errors of the U-type Adcock direction-finder. These errors arise from the introduction of signal voltages into the system by the horizontally polarized component of the incident waves, when the aerial feeders are laid on, or buried in, ground of poor conductivity. The polarization error of a standard form of direction-finder, erected in the normal manner on highly conductive ground (3 ? 108 e.s.u., or about 3 ? 103 ohm-cm resistivity) at the Radio Research Station, Slough, was measured over the frequency range 3?10 Mc/s, with the aid of a local transmitter which radiated at controllable angles of incidence and polarization. An earth mat, about 31 m in diameter and of a square mesh between 0.3 and 1 m, was then installed at the direction-finder, and the measurements were repeated for various experimental arrangements of this installation. When the mat was raised above and insulated from the ground, the polarization error of the direction-finder was seriously increased; but when the mat was effectively earthed (both around its perimeter and at an intermediate radius) the error was slightly reduced. In place of the direct earth connection, a similar result was achieved by attaching radial wires to the perimeter of the mat, the length of the wires being selected to resonate at the frequency in use. By using a combination of 108 wires of 11, 15 and 25 m lengths, arranged so that there were 36 of each length, the desired reduction in the polarization error was attained more or less uniformly over the whole of the 3?10 Mc/s range. Additional experiments were carried out at Martlesham on ground of such poor conductivity (107 e.s.u., or about 105 ohm-cm resistivity), that direct earth connection to the mat was ineffective. The results confirmed the previous deduction that the attachment of radial wires of suitable length and disposition make-ns the earth mat effective. It was also shown that both mat and radial extension wires may be laid on the ground if desired. Furthermore, it was shown that, with the mat in position, it was no longer necessary to bury the aerial feeders, but was sufficient to lay the feeders on the ground just under the mat, or along the surface of the mat, if the feeder screen was well bonded to the mat. An additional advantage of the use of such an arrangement is that it smooths out the effects of any irregularities in the ground at the site, and produces a corresponding improvement in the performance of the direction-finder. Comparison of observations made at the same site with two direction-finders, one equipped with an earth mat and one without, showed that when taking bearings on signals from stations at distances ranging from 200 km to nearly 800 km, the expected appreciable improvement in overall performance due to the mat was attained.
机译：该论文涉及1943-44年间进行的实验，以研究使用地线筛网或垫子来减少U型Adcock测向仪的极化误差。这些误差是由于在将架空馈线放置或埋在导电性较差的地面上时，入射波的水平极化分量将信号电压引入系统而引起的。在整个频率范围内，测量了标准形式的测向仪的极化误差，该误差通常以正常的方式竖立在斯劳无线电研究站的高导电性地面上（3？108 esu，或大约3？103 ohm-cm电阻率）。在本地发射器的帮助下，发射范围为3？10 Mc / s，该发射器以可控制的入射角和偏振角辐射。然后将一个直径约31 m且方孔在0.3到1 m之间的地垫安装在测向仪上，并对该安装的各种实验布置进行重复测量。当垫子抬高并与地面绝缘时，测向仪的偏振误差会大大增加；但是当垫子有效接地时（围绕垫子的周长和中间半径），误差会略有降低。通过将径向导线连接到垫子的周围，可以代替直接接地，从而获得相似的结果，导线的长度选择为在使用频率下产生共振。通过使用长度分别为11、15和25 m的108根导线的组合，使得每根长度分别为36，可以在3？10 Mc / s的整个过程中大致均匀地实现所需的偏振误差降低。范围。在Martlesham上以导电性很差（107 e.s.u.，或约105 ohm-cm的电阻率）为基础进行了另外的实验，结果表明直接接地到垫子是无效的。结果证实了先前的推论，即适当长度和布置的径向线的连接使接地垫有效。还显示出，如果需要，垫子和径向延伸线都可以铺设在地面上。此外，已经表明，在垫子就位的情况下，不再需要掩埋空中给料器，而是足以将给料器放置在垫子下方的地面上，或者沿着垫子的表面放置（如果给料器）屏幕与垫子牢固粘合。使用这种装置的另一个优点是，它消除了现场地面上任何不平整的影响，并在测向仪的性能上产生了相应的改进。比较在同一地点使用两台测向仪进行的观测，其中一台装有地垫，一台没有地垫，当接收来自200 km至近800 km距离的测站的信号时，总体上预期会有明显改善由于垫子而获得的性能。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号