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首页> 外文期刊>Proceedings of the IEE - Part IV: Institution Monographs >The ionospheric propagation of radio waves with frequencies near 100kc/s over distances up to 1000 km
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The ionospheric propagation of radio waves with frequencies near 100kc/s over distances up to 1000 km

机译：频率高达100kc / s的无线电波在1000公里以内的电离层传播

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摘要

In a companion paper1 the authors have presented the results of a scries of measurements of the characteristics of the downcoming wave observed at a frequency near 100 kc/s at a distance of about 100 km from the sender. In this paper, the results of a complementary series of experiments at greater distances from the sender are discussed. The measurements have been made at frequencies between 70 and 128 kc/s. From measurements of the Hollingworth interference pattern, the apparent height of reflection at oblique incidence (for distances greater than 400 km) has been found to be approximately 70 km at midday in summer, and no definite variation of height with frequency has been detected. The reflection coefficient deduced from the same measurements was found to increase steadily with distance, from 0.02 at 300 km to 0.09 at 800 km from the sender for a frequency of 70 kc/s. The reflection coefficient is found to be less on the higher frequencies. In winter the reflection coefficients at oblique incidence are found to be roughly double the summer values. Up to 350 km from the sender, the diurnal and seasonal variations of apparent height and of absorption appear to be very similar to those reported in the companion paper for 100 km from the sender. The absorption increases about 1 hour before ground sunrise and the apparent height does not begin to fall until very near ground sunrise, when it decreases by about 8 km; this is in good correlation with the observations at shorter distances. When observations are made at distances of 850?950 km from the senders, it is found that both the absorption and the apparent height change about one hour before ground sunrise at the mid-point of the path and that the decrease of apparent height is of the order of 20 km. During a sudden ionospheric disturbance it is found that, at distances of 850?950 km from the sender, the amplitude of the sky wave increases by a factor up to 5 and sometimes reaches its nighttime value. This behavio-nur is in marked contrast with the observations at short distances, when the amplitude of the downcoming wave is very much reduced. The apparent height of reflection decreases by about the same amount as is observed at shorter distances.
机译：在同伴论文1中，作者提出了一系列测量结果的结果，这些测量结果是在距发送方约100 km的附近以100 kc / s的频率观察到的。在本文中，讨论了距离发件人较远的一系列补充实验的结果。在70至128 kc / s之间的频率下进行了测量。根据Hollingworth干涉图样的测量，在夏季中午，斜入射（距离大于400 km）的表观反射高度约为70 km，并且未检测到高度随频率的确定变化。发现从相同的测量结果推导出的反射系数随着距离的增加而稳定增加，从70 km / s的频率到300 km，从300 km处的0.02到800 km处的0.09。发现反射系数在较高频率上较小。在冬季，倾斜入射时的反射系数大约是夏季值的两倍。距发件人最多350公里，表观高度和吸收率的日变化和季节性变化似乎与伴侣论文中距发件人100 km的每日变化非常相似。吸收率在地面日出之前约1小时开始增加，并且视高度直到直到非常接近地面日出才开始下降，直到8 km时才降低。这与较短距离的观测值具有很好的相关性。在距发送者850-950 km的距离处进行观察时，发现吸收和表观高度都在地面日出之前约一小时在路径的中点发生了变化，并且表观高度的减小幅度是大约20公里在突然的电离层扰动中，发现在距发射器850-950 km的距离处，天波的振幅增加了多达5倍，有时达到了夜间值。当下降波的幅度大大减小时，这种行为与短距离观测结果形成鲜明对比。反射的表观高度减少的程度与在较短距离处观察到的减少程度大致相同。

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