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What is WiFI Signal Strength and Why Should I Care?

Let’s take a deeper look at WiFi signals and how they can impact your wireless network usage.
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More and more households and businesses are moving to WiFi networks as their preferred method of providing Internet access. Wireless networks are more convenient for end users and enable everyone to take full advantage of their mobile devices. They also eliminate the cabling necessary to implement a more traditional wired network.

The benefits of WiFi networks are accompanied by some additional concerns that must be addressed from an administrator’s point of view. It’s not just a matter of supplying enough connections for all of your users. You need to be aware of aspects of your network such as coverage area and channel overlap.

For those of us with home WiFi networks, we are our own network admins. If you are in this situation or are just a curious end user, one of the characteristics of your network that you need to understand is the WiFi signal strength. This value will be a determining factor in the activities for which your network can be used. Let’s take a deeper look at WiFi signals and how they can impact your wireless network usage.

What is a WiFi Signal?

A WiFi network employs radio waves to establish communication between devices. These devices may include computers, mobile phones, tablets or network routers. The wireless network router is the interface between a wired connection to the Internet or other Ethernet network and the wirelessly connected devices.

The router decodes radio signals received from the users of the WiFi network and transmits them to the Internet. Conversely, data received from the Internet is converted from binary data into radio waves for distribution to the devices that are using the network.

The radio waves which comprise WiFi signals make use of the 2.4 GHz and 5 GHz frequency bands. These are higher than the frequencies used for televisions or cell phones and allow more data to be carried than do the lower frequencies.

WiFi signals use the 802.11 networking standards when transmitting data. There are a number of different varieties of the protocol that are used in WiFi networking. Some of the more common ones you will see are 802.11n which is used on the 2.4GHz band and 802.11ac primarily used for 5GHz transmission. Others you might see are 802.11b which is the slowest standard and 802.11g.

What is a Good Wifi Signal Strength?

The strength of the WiFi signal throughout the network’s coverage area directly impacts the ability of users to perform various activities in a timely manner. Before delving into which signal strengths are appropriate for certain uses of your WiFi network, let’s discuss how WiFi signals strengths are measured.

The most consistent method of indicating signal strength is with a quantity known as a dBm. This term stands for decibels relative to a milliwatt and is expressed as a negative number from 0 to -100. Therefore, a signal of -40 is more powerful than a signal of -80 since -80 is further from 0 and therefore a smaller number.

The dBm scale is logarithmic rather than linear, which means that the changes between signal strengths do not scale in a smooth and gradual manner. On this scale a difference of 3 dBm leads to a halving or doubling of the previous signal’s strength.

Background noise levels that can impact your WiFi performance are also expressed in dBms. In the case of noise levels, a value close to zero indicates high levels of noise. Noise measured at -10 is greater than that of -40.

The following table indicates the minimum signal strengths that you should strive for in order to use your WiFi network for various purposes.

Signal Strength Qualifier Suitable Uses
-30 dBm Excellent This is the maximum achievable signal strength and will be appropriate for any usage scenario.
-50 dBm Excellent This excellent signal level is suitable for all network uses.
-65 dBm Very Good Recommended for supporting smartphones and tablets.
-67 dBm Very Good This signal strength will be sufficient for voice over IP and streaming video.
-70 dBm Acceptable This level is the minimum signal strength required to ensure reliable packet delivery and will allow you to surf the web and exchange emails.
-80 dBm Bad Enables basic connectivity but packet delivery is unreliable.
-90 dBm Very bad Mostly noise that will inhibit most functionality.
-100 dBm Worst Total noise.

What Factors Can Impact WiFi Signal Strength?

There are a number of factors that can impact the strength of your network’s WiFi signal. Some of them are:

Router location

There are several different aspects of your router’s location that can impact its ability to deliver a good signal throughout your intended coverage area. These include:

  • The height of the router – You should locate your router as high as possible. Placing it on the floor or on low shelves will impede its ability to provide a strong signal.

  • Central location – You will obtain the best WiFi coverage if your router is located centrally in your home or office. Placing it in a corner of the house will result in WiFi leakage and reduced signal in your coverage area.

  • Interference from other devices – Microwaves and cordless phones may use the same frequency band as your WiFi router and contribute background noise that impacts the signal level.

  • Walls and floors – The best WiFi signal will be obtained if the devices that will be using the router have a clear line of sight to it. Signals that travel through walls and floors will have their strength negatively affected.

Keep Your Router up to Date

Configure your router for automatic firmware updates to keep it operating at peak efficiency. It is also a good practice to periodically reboot your router.

Distance From the Router

Devices that require strong signals such as those that will be used for gaming or streaming may obtain better performance by being located close to the router. In some cases, you may need to boost the WiFi signal by employing additional equipment such as routers to extend your WiFi’s range.

How to Test Your WiFi Signal Strength

In order to determine your WiFi signal strength, your best course of action is to use a WiFi signal strength app like NetSpot. Installing this excellent WiFi analyzer on a laptop or mobile device will allow you to test the strength of the WiFi signal throughout your coverage area. Here’s how to do it.

  1. Download and install the NetSpot application on your Windows laptop, Android device or MacBook. The free version is sufficient to get your WiFi signal strength.

  2. Launch the application and select Discover from the top of the app’s main window.

Discover Mode NetSpot
  1. Identify your WiFi network from among those that the app discovers.

  2. You will be presented with a number of statistics regarding your network and among them is the signal strength.

  3. Take note of the strength in your current location and proceed to move around your coverage area with the device that is running NetSpot.

  4. Perform a systematic survey of your coverage area while noting the WiFi signal strength to alert you to problem areas that may need to be addressed in order to use your network as you intended.

Wi-Fi Site Surveys, Analysis, Troubleshooting runs on a MacBook (macOS 10.10+) or any laptop (Windows 7/8/10) with a standard 802.11a/b/g/n/ac wireless network adapter.
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The strength of your WiFi is a critical component of your network that impacts how you make use of it. Monitoring the signal strength and making adjustments when necessary will go a long way toward maintaining the type of WiFi network performance that your users deserve.

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Wi-Fi Site Surveys, Analysis, Troubleshooting runs on a MacBook (macOS 10.10+) or any laptop (Windows 7/8/10) with a standard 802.11a/b/g/n/ac wireless network adapter.