Deciding where to place a Wi-Fi router at home to minimise signal blackspots is a fine art. But a physicist has attempted to tackle the problem by mathematically working out the optimum position for a router. He studied how walls and reflections affected signal strength and concluded that, as common sense might suggest, there’s just no beating the centre of a house for router location。

决定在家里的什么位置放置无线路由器来最大程度减少盲点是一门艺术。近来，一位物理学家最近试图用算法来规划处路由器的最佳位置。他研究了墙壁对WiFi信号强度的影响，得出一个似乎是显而易见的结论：没有比房子正中间更好的位置了。

The 'complex' research was carried out by Jason Cole, a PhD physics student at the John Adams Institute at Imperial College London. Frustrated at finding numerous Wi-Fi blackspots around his flat, Mr Cole turned to mathematics to find out how he could improve his internet connection. He found that, the waves were hindered not only by walls and closed doors but also when they went around corners. This, he says, is because the signal loses strength when it bounces off objects。

这项“复杂”的实验由杰森·科尔，来自伦敦帝国学院约翰·亚当斯研究所的物理博士进行。在自己的公寓发现了太多WiFi信号盲点，科尔选择采取算法提高网络连接速度。他发现WiFi的信号流不止被墙壁和门阻挡，同样也会在角落里减弱。他认为这是因为当信号接触物体之后会减少一些能量。

‘I found an equation which approximates the behaviour of high-frequency electromagnetic waves such as Wi-Fi, and tried to solve it by placing a virtual router in the floor plan of my flat. After crunching numbers for a few minutes I was able to generate maps of Wi-Fi signal strength inside the flat, showing poor signal near my computer.’

“我发现了一个方程式，它能计算出WiFi这类高频电磁感应信号的运动轨迹，我在公寓地板上设置了一个虚拟路由。在测试一段时间的信号之后，我就能够绘制出WiFi信号在公寓内强弱的图表，发现电脑旁边较弱的信号。”

By showing how weakened the signal can be when it moves across the flat, Mr Cole found that no matter where his router was placed at one side of the flat, there would always be blackspots elsewhere. Instead, he suggests that the only solution to ensure as few blackspots as possible is to place the router in the middle of the flat。

通过移动虚拟路由器的位置，可以看到信号强弱的变化。科尔发现无论将路由器放在公寓的哪一边，其他地方都会有盲点。因此，他觉得尽可能减少盲点的最佳方式就是把路由器放在公寓中间。

‘There is also some reflection of the signal around corners, but engineers tell me reflections are bad too. In my case, the best position was as central as possible, preferably near open doorways. He says he hasn’t tried any physical tests of the simulation yet, but has been given suggestions by commenters on his website. There have been many other helpful comments which will no doubt improve the methodology in the future, and a surprising number of people asking for an app to test their own houses or offices, so there's plenty of work to do.’

“角落里同样也有信号反射，但是工程师告诉我反射很弱。因而，最佳的位置是在房间的尽可能中心位置，最好离门口近些。他说他还没有进行任何物理实验，但是网站上有人给出了建议。这些建议有的会为未来的方法论提出更好的改进措施，而且令我们惊讶的是，很多人希望能有一款测试自己家里或者办公室里信号强弱的app，所以我们还有很长的路要走。”

ARE WI-FI SIGNALS DANGEROUS?

Wifi信号危险吗？

Wi-Fi signals use very low intensity radio waves. Whilst similar in wavelength to domestic microwave radiation, the intensity of Wi-Fi radiation is 100,000 times less than that of a domestic microwave oven。

Wifi信号运用的是非常低强度的无线电波，其波长与家用微波辐射相似，而其强度则比家用微波炉要弱10万倍。

The type of radiation emitted by radio waves (Wi-Fi)， visible light, microwaves and mobile phones has been shown to raise the temperature of tissue at very high levels of exposure.This is called a thermal interaction, but researchers are divided as to whether the radiation we receive daily can cause damage。

由无线电波(如Wifi)，可见光，微波和手机发出的辐射，在长时间照射下会使物体温度升高。这被称作热互作用，但是针对这种辐射是否会对人身体产生危害，调查者们持不同意见。

The UK Health Protection Agency (HPA) has been monitoring the safety of Wi-Fi. It says people using Wi-Fi, or those in the proximity, are exposed to the radio signals it emits - and some of the transmitted energy in the signals is absorbed in their bodies。

英国健康保护署曾检测Wifi的安全性。它的调查结果称，使用或者接近Wifi的人群都在其辐射范围内，而且信号中传送的一些能量会被吸取进身体中。

However, the signals are very low power. Sitting in a Wi-Fi hotspot for a year results in receiving the same dose of radio waves as making a 20 minute mobile phone call。

然而，这些信号的能量很低。在Wifi热点附近坐上一年所吸取的辐射，大约等于20分钟通话所产生的无线电波。