无线网络(wireless network)连接速度慢且不稳定的最常见根本原因之一是干扰。许多事物都会干扰无线网络(wireless network)：从墙壁到您在厨房中使用的微波炉再到其他无线网络(wireless network)。这就是为什么我决定更多地了解这个主题，用我自己的无线网络进行试验并分享(wireless network and share)我所学到的东西。
在本文中，您将了解更多关于什么会干扰您的无线网络(wireless network)，并学习如何处理来自其他无线网络(wireless network)的干扰。
无线网络干扰问题(Wireless Network Interference Problems)的原因和症状(Causes & Symptoms)
有许多可能的原因会导致您的无线网络(wireless network)出现干扰问题：
- 放置网络的物理环境：找到无线网络的公寓、办公楼或(wireless network)房屋(office building or house)。墙壁和门会干扰您的网络信号，降低其强度和传输速度(transfer speed)。
- 您正在使用的电子设备：微波炉、无绳电话、无线耳机、蓝牙(Bluetooth)设备、监控摄像头以大多数无线网络使用的 2.4 吉赫 ( GHz ) 频率运行。(GHz)
- 与路由器或发射无线信号的设备的物理距离。距离越远，信号越弱越弱。这总是转化为受到不同类型干扰影响的更高可能性。
- 最后但并非最不重要的一点是，其他无线网络可能会干扰您的无线网络。
当您的无线网络(wireless network)出现干扰问题时，您可能会遇到一种或多种症状：WiFi 网络(WiFi network)范围缩小（通常远低于路由器制造商在硬件规格中提及的范围）、传输速度突然下降、无线信号丢失在白天的某些地方或某些时间，您的无线信号强度会随机上升和下降。
是什么让无线网络相互干扰(Makes Wireless Networks Interfere)？
如果两个或多个无线网络彼此靠近，则在以下情况下它们可能会相互干扰：
- 它们使用相同的工作频率(operating frequency)（2.4 GHz或 5 GHz）。802.11g 和 802.11b 标准使用 2.4 GHz 工作频率(operating frequency)，802.11n 可以同时工作在 2.4 GHz和 5 GHz，而 802.11a 只能工作在 5 GHz。
- 它们使用相同的频道或(channel or neighboring channels)重叠的相邻频道。无线路由器可以使用设置的频道(set channel)发送无线信号，从 1 到 11 或 13（取决于路由器型号(router model)和销售地点）。为确保与其他通道重叠的可能性较小，您应该选择通道 1、6 或 11（或 13，如果您的路由器可用）。默认情况下，大多数路由器都设置为使用通道 6(channel 6)，这就是冲突的原因。
(Identify Interference Problems)使用 inSSIDer识别来自其他无线网络的(Wireless Networks)干扰问题
确定干扰问题的确切根本原因(root cause)可能会非常痛苦，具体取决于您所在的位置。如果您在周围有很多无线网络的繁忙地区，那么您的问题很可能是由其他网络引起的。
那么......你如何修复它们？您可以使用名为inSSIDer的工具（工作下载链接：此处(here)）。我们在之前的教程中介绍了使用它的基础知识：查找隐藏的无线网络并查看有用信息(Find Hidden Wireless Networks & View Useful Information)（包括SSID）。我建议您先阅读它，然后再按照本文中的说明进行操作。
假设您正在尝试解决自己家中的干扰问题。在笔记本电脑上安装该工具并启动它。查看它识别的无线网络并查看它们是如何设置的。从靠近路由器的地方开始，在房子周围移动到它的四肢和你遇到最多问题的区域。(Start)
注意(Pay attention)无线网络是如何从雷达上消失或出现的。查看您的网络信号如何演变。在您遇到最多问题的区域中，您很可能有其他无线网络处于活动状态。
然后，查看数据并问自己以下问题：
- 我的无线网络在哪个频率上（5 GHz或 2.4 GHz）？
- 我可以将路由器切换到网络数量最少的工作频率吗？(operating frequency)
- 我的网络使用的是哪个频道？
- 我所在地区的无线网络最少使用哪些信道？
干扰问题的可能解决方案(Problems)
如果您的路由器完全支持 802.11n 标准，您可以使用它并切换到 5 GHz 工作频率(operating frequency)。但是，这可能会导致您需要注意的一些问题。首先(First)，无线网络信号(wireless network signal)将无法像使用 802.11b 标准时那样穿透。它更容易被墙壁、门和其他固体物体吸收。如果覆盖大面积很重要，您可能不想走这条路线。然后，另一个问题是由对该标准的支持引起的。较旧的笔记本电脑、智能手机和无线适配器不支持它。测试您的旧设备并了解(equipment and learn)它在使用 802.11n 标准时是否可以检测并连接到无线网络。(wireless network)
如果您有一个可以在 2.4 GHz和 5 GHz下运行的双频(GHz)路由器(band router)，那么您可以将较新的设备连接到 5 GHz 无线(GHz wireless)网络，将旧设备连接到 2.4 GHz 网络(GHz network)。根据您的路由器，在这种情况下，您可能会遇到文件共享问题以及设备和计算机如何通过网络相互检测。不要犹豫，通过测试并检查文件共享是否按需要工作。
如果无法更改工作频率(operating frequency)和无线标准，那么您必须分析您所在地区所有无线网络使用的信号。
在本文使用的屏幕截图中，我的家庭网络(home network)名为C1pr1an。它使用通道 7 进行操作。我所在地区的大多数网络都使用频道 6(area use channel 6)。如果查看 2.4 GHz 选项卡(GHz tab)，我可以看到我的无线网络(wireless network)信号如何与许多网络重叠，尤其是那些使用信道 6 的网络。很明显，最好更改信道。
我应该选择哪个频道？1、11 还是 13？记住(Remember)……走极端更好。
我看到我所在地区的 3 个信号强度较低的网络使用了通道 1 。(channel 1)RSSI 列(RSSI column)向我展示了它的强度 - 数字越大，信号越强。
在频道 11 上，有两个信号稍好一些的网络。幸运的是，我的路由器最多提供 13 个通道（有些路由器没有）。在13 频道(channel 13)上，我所在地区只有一个信号强度较低的网络。
所以..我应该切换到哪个频道？你猜对了……第 13 频道(channel 13)。如果我不能使用频道 13(channel 13)，那么我最好的选择是频道 11，因为它上面的活动网络较少。
下面是我如何使用inSSIDer的精彩视频摘要：
最后但同样重要的是，查看您的无线网络(wireless network)的配置选项。某些路由器具有在打开时有助于以更好的方式处理干扰的功能。例如，Belkin路由器有一个保护模式(Protected Mode)设置，可以在高干扰区域启用。
最终结果(End Result)：几乎没有冲突和更好的吞吐量(Almost No Conflicts & Better Throughput)
更换频道后，我用inSSIDer 再次分析了(inSSIDer)情况(situation one)。
在我遇到问题最多的地区，情况看起来要好得多。我的无线网络(wireless network)不再干扰那些信号强度(signal strength)好的网络，使用信道 6。
在我几乎没有问题的房子区域，现在一切都很完美。我的无线(My wireless)网络在其他无线网络干扰为零的信道上运行。
其他干扰(Interference)源呢？
本文的目的是展示如何处理干扰您网络的其他无线网络。如果您有兴趣了解如何处理其他可能的根本原因，我推荐以下来源：
帮助改善无线网络的 10 个技巧(10 tips to help improve your wireless network)
Wi-Fi 干扰的 20 个误区(20 Myths of Wi-Fi Interference)
创建inSSIDer的人还有一个YouTube 视频(YouTube video)频道，他们在其中发布有用的教程，介绍其他可用于识别干扰问题来源的出色工具。你可以在这里找到它：MetaGeek Trent。
The Layman's Guide to Solving Wireless Network Interference Problems
One of the most cоmmon root causes for having slow and unstable wireless netwоrk connections is intеrference. Many things interfere with a wireless network: everything from walls to the microwaves you use in the kitchеn to other wireless networks. That's why I decided to learn more on the subject, experiment with my own wirelesѕ network and share what I have learned.
In this article, you will understand more about what can interfere with your wireless network and learn how to deal with interferences from other wireless networks.
The Causes & Symptoms for Wireless Network Interference Problems
There are many possible causes for having interference problems with your wireless network:
- The physical landscape where your network is placed: the apartment, office building or house where the wireless network is found. Walls and doors interfere with the signal of your network, lower its strength and the transfer speed.
- Electronic equipment you are using: microwave ovens, cordless phones, wireless headsets, Bluetooth devices, surveillance cameras operate at the 2.4 gigahertz (GHz) frequency used by most wireless networks.
- The physical distance from the router or the device emitting the wireless signal. The further away, the weaker the signal weaker. This always translates into a higher likelihood of being impacted by different kinds of interference.
- Last but not least, other wireless networks can interfere with yours.
When your wireless network has interference problems you can encounter one or more symptoms: reduced range for your WiFi network (generally much lower than what the manufacturer of your router mentions in the hardware specifications), sudden drops in transfer speeds, the wireless signal dropping out in certain places or at certain times during the day, your wireless signal strength going up and down randomly.
What Makes Wireless Networks Interfere With Each Other?
If two or more wireless network are placed close to one another, then they can interfere with each other if:
- They use the same operating frequency (2.4 GHz or 5 GHz). The 802.11g and 802.11b standards use the 2.4 GHz operating frequency, 802.11n can operate both at 2.4 GHz and 5 GHz while 802.11a can operate only at 5 GHz.
- They use the same channel or neighboring channels which overlap. A wireless router can send the wireless signal using a set channel, from 1 to 11 or 13 (depending on the router model and where it is sold). To make sure there is a smaller likelihood of overlapping with other channels, you should choose channel 1, 6 or 11 (or 13 if available for your router). By default, most routers are set to use channel 6, thus the reason for conflicts.
Identify Interference Problems from Other Wireless Networks With inSSIDer
Identifying the exact root cause for your interference problems can be quite a pain, depending on your location. If you are in a busy area with lots of wireless networks around, then your problems are most likely caused by the other networks.
So... how do you fix them? You can use a tool named inSSIDer (working download link: here). We covered the basics of using it in a previous tutorial: Find Hidden Wireless Networks & View Useful Information (Including the SSID). I recommend that you read it first, before going ahead with the instructions in this article.
Let's assume you are trying to fix interference problems in your own home. Install the tool on a laptop and fire it up. Look at the wireless networks it identifies and look at how they are set. Start somewhere close to the router and move around the house to its extremities and to the areas where you encounter most issues.
Pay attention to how wireless networks disappear from the radar or show up on it. View how your network signal evolves. In the areas where you encounter most issues, you most probably have other wireless networks active.
Then, look at the data and ask yourself the following questions:
- On which frequency is my wireless network (5 GHz or 2.4 GHz)?
- Can I switch the router to the operating frequency where the fewest number of networks is found?
- Which channel is my network using?
- Which channels are least used by the wireless networks in my area?
Possible Solutions to Your Interference Problems
If your router fully supports the 802.11n standard, you can use it and switch to the 5 GHz operating frequency. However, this can cause some problems you need to be aware of. First, the wireless network signal will not be able to penetrate as far as when using the 802.11b standard, for example. It is better absorbed by walls, doors and other solid objects. If covering a large area is important, you might not want to go this route. Then, another issue is caused by support for this standard. Older laptops, smartphones and wireless adapters do not support it. Test your older equipment and learn if it can detect and connect to the wireless network when using the 802.11n standard.
If you have a dual band router, that can operate both at 2.4 GHz and 5 GHz, then you can connect the newer devices to the 5 GHz wireless network and the older equipment to the 2.4 GHz network. Depending on your router, in this scenario, you can encounter issues with file sharing and how devices and computer detect each other over the network. Don't hesitate to test things through and check if file sharing works as needed.
If changing the operating frequency and the wireless standard is not an option, then you have to analyze the signal used by all wireless networks in your area.
In the screenshots used in this article, my home network is named C1pr1an. It uses channel 7 to operate. Most networks in my area use channel 6. If look on the 2.4 GHz tab, I can see how my wireless network signal overlaps with many networks, especially with those using channel 6. It is clear that it is best to change the channel.
Which channel should I pick? 1, 11 or 13? Remember... going to the extremes is better.
I see that channel 1 is used in my area by 3 networks with low signal strength. The RSSI column shows me its strength - the higher the number, the stronger the signal.
On channel 11 there are two networks with slightly better signal. Luckily, my router provides up to 13 channels (some routers do not). On channel 13 there is only one network in my area with low signal strength.
So.. to which channel should I switch? You guessed it... channel 13. If I could not use channel 13, then my best choice would have been channel 11 because fewer networks are active on it.
A good video summary of how I used inSSIDer can be found below:
Last but not least, look at the configuration options for your wireless network. Some routers have features that, when turned on, help in dealing with interference in a better way. For example, Belkin routers have a Protected Mode setting that can be enabled for areas with high interference.
The End Result: Almost No Conflicts & Better Throughput
After changing the channel, I have analyzed the situation one more time with inSSIDer.
In the area where I had the most problems, the situation looks much better. My wireless network no longer interferes with those networks with good signal strength, using channel 6.
In the area of the house where I had almost no issues, things are perfect now. My wireless network is functioning on a channel with zero interference from other wireless networks.
What About the Other Sources of Interference?
The intent of this article was to show how to deal with other wireless networks interfering with yours. If you are interested in learning how to deal with other possible root causes, I recommend the following sources:
10 tips to help improve your wireless network
20 Myths of Wi-Fi Interference
The folks that created inSSIDer also have a YouTube video channel where they post useful tutorials about other great tools you can use to identify the source of your interference problems. You can find it here: MetaGeek Trent.
