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首页> 外文期刊>Electrical Engineers - Part III: Radio and Communication Engineering, Journal of the Institution of >An experimental spaced-loop direction-finder for very high frequencies
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An experimental spaced-loop direction-finder for very high frequencies

机译：实验性间隔环测向仪，用于非常高的频率

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摘要

A description is given of an experimental spaced-loop direction-finder for use with vertically polarized waves in the frequency range 30????????100 Mc/s (10-3 m). The screened loops are 28 cm square and are mounted coaxially with a spacing of 1.57 m. The sensitivity of the system in conjunction with a good commercial receiver is such that a field strength of 20 ????????V/m is required for a silent swing of ???????± 5???????°. Means are provided for selecting the required minima of the polar diagram. Instrumental errors are liable to become excessive at the resonant frequencies of the aerial system or its screen, but may be minimized by careful construction and adjustment of the system. Reciprocal error can be reduced to less than ???????? deg at all frequencies in the above range. No satisfactory method exists for measuring any small residual polarization errors of a spaced-loop system, because the curvature of the wavefront from a local transmitter introduces polarization errors which would not be present with a distant transmitter. Errors measured with a local test transmitter at an angle of elevation of 25???????° with a dipole aerial inclined at 60???????° to the vertical have been compared with calculated errors due to wavefront curvature alone. It is estimated that there were no instrumental polarization errors in excess of 2 deg in the frequency range 30????????100 Mc/s under the above test conditions. A brief account is given of a more sensitive system with loops 92 cm square, designed for a small frequency range around 30 Mc/s (10 m). In the Appendix an analysis is made of the polarization errors due to the proximity of a local test transmitter.
机译：给出了一个实验性间隔环测向仪的描述，该测距仪用于频率范围为30≤100 Mc / s（10-3 m）的垂直极化波。屏蔽环的面积为28平方厘米，同轴安装，间距为1.57 m。该系统的灵敏度与良好的商用接收机相结合，以使20Ω···V / m的场强为±5Ω的无声摆幅。 ????°。提供了用于选择极坐标图的所需最小值的装置。仪器误差在航空系统或其屏幕的共振频率处可能会变得过大，但可以通过仔细构造和调整系统来将其降低到最小。倒数误差可以减小到小于????????在上述范围内的所有频率下的度数。由于存在来自本地发射器的波前曲率会引入偏振误差，而远程发射器不会出现这种偏振误差，因此没有任何令人满意的方法可用于测量间隔环系统的任何较小残留偏振误差。用本地测试发射机在仰角为25°且偶极天线垂直于60°时测得的误差与波前曲率引起的计算误差进行了比较单独。据估计，在上述测试条件下，在30°≤100Mc/ s的频率范围内没有超过2度的仪器偏振误差。简要介绍了一个灵敏度更高的系统，该系统的环路面积为92平方厘米，设计用于30 Mc / s（10 m）左右的较小频率范围。在附录中，分析了由于本地测试发射机的接近而引起的极化误差。

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