天气预报15天查询> 其他> u段和v段哪个距离远

u段和v段哪个距离远

更新时间: 2020-11-13 00:00:00     

u段属于UHF频段,直射波传播比V段更甚,U段穿透力较V段要好,所以在高楼林立的城市用U段的比较多。但同时空气的衰减比V段大,不适合于作远距离通讯。

在夏季等天气不稳定的季节,常会产生叫“大气波导”的异常传播现象,电波在大气三层温度突变层间来回折射,衰减很小地传到远方。还有流星余迹反射和对流层散射等现象,也会使此频段的电波超视距的传播。

关键词: 哪个 距离

如有意见、反馈、侵权或投诉等情况,请联系:

电话:
邮箱:

我们将会在48小时内给与处理!

版权所有 Copyright ? 2009-2020 tianqiyubao3.com

页面:/news/view-2442164/ | 耗时:0.8179 s | 内存:1.89 MB | 查询:4 | 缓存读取:4 写入:0 | 加载文件:23
select * from tbl_Articles WHERE ArticleID=2442164 LIMIT 0,1
select * from tbl_Articles_data WHERE ArticleID=2442164 LIMIT 0,1
select * from tbl_Articles_sphinx where id=2442164 LIMIT 0,1
SELECT ArticleID,Title FROM tbl_Articles WHERE ArticleID IN(168274,1092211,1121385,1125522,1294251,759570,564855,1116047,1123413,1120273,1117450,1124013,1112160,1108562,1540021,1132345,1100515,357621,176808,606367,1088694,428326,1277661,353401,1130894,174507,1118757,595825,1092690,533152) ORDER BY field (ArticleID,168274,1092211,1121385,1125522,1294251,759570,564855,1116047,1123413,1120273,1117450,1124013,1112160,1108562,1540021,1132345,1100515,357621,176808,606367,1088694,428326,1277661,353401,1130894,174507,1118757,595825,1092690,533152)