当您设置远程Wi-Fi连接时，您希望确保您的连接尽可能牢固，但是您是否可以使用多种天线类型的混合天线，还是只使用高增益天线？今天的超级用户问答有一个困惑读者的问题的答案。

今天的问答环节是由SuperUser提供的，SuperUser是Stack Exchange的一个分支，是一个由社区驱动的问答网站分组。

照片由Karlis Dambrans（Flickr）提供。

问题

超级用户读者userpal想知道他是否需要在远程Wi-Fi连接的两端安装高增益天线：

I am trying to understand how long range Wi-Fi works. As far as I know, Wi-Fi c***ists of Rx and Tx. When a laptop is connected to an AP, the laptop is able to receive data from the AP (Rx) and also tran**it data back to the AP (Tx).

Suppose I want to build a long range Wi-Fi setup to cover a large area and I connect a high-gain omni-directional antenna like the one shown in this diagram to the AP.

So assume that the original AP’s Wi-Fi signal radius is 250 meters, but by using the high-gain antenna, the radius become 1,000 meters.

At 1,000 meters away from the AP and using a normal laptop (without a high-gain antenna), I try to connect to the AP. The signal from the AP is able to reach the laptop, but the signal from the laptop should not be able to reach the AP. Under these conditi***, can the laptop actually connect to the AP?

Wi-Fi diagram courtesy of Freeman’s Garage Blog.

用户是否真的需要高增益天线两端的远程Wi-Fi连接与否？

答案

超级用户贡献者mgjk、Jamie Hanrahan和David Cary为我们提供了答案。首先，mgjk：

The antenna changes the shape of the tran**ission. The electrical signal does not become more powerful, but less is wasted during tran**ission in directi*** which are not useful (i.e. up and down).

Similarly with reception, the signals are received from a more narrow field, which strengthens reception and reduces interference.

It is similar to talking through a cone, then listening through the cone for a resp***e. The person at the other end does not need any special equipment, but you have increased the range and sensitivity.

接下来是杰米·汉拉汉的回答：

High-gain antennas provide gain on both tran**itting and receiving. So, with such an antenna at only one end, you will get more range than with a standard antenna at each end, but less than with a high gain antenna at both ends.

大卫·卡里最后的回答是：

You might also mention antenna reciprocity — if a directional antenna can tran**it four times as far as a standard antenna, then the same directional antenna can receive from four times as far away as a standard antenna.

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