Don’t Buy a Wi-Fi Range Extender Without Reading This First

A Wi-Fi range extender may not be the best idea for improving wireless network performance.

My home office is as far away from the master bedroom as possible. That’s generally a good thing, but it’s not good when it comes to the wireless network. The Internet connection enters at my office, and that’s where the main Wi-Fi router is located. That means the signal has to make it through thick rammed earth walls to get to the master bedroom. I need some signal there so I can watch home-repair videos during the day or movies at night.

Why the Wi-Fi signal gets slower with distance from the access point

The wireless network is, well, wireless. It uses radios to send and receive data. As one moves further from the transmitter, the signal diminishes in intensity or attenuates. Additionally, the electrical radio-frequency noise found in any office or home impacts the signal. That means that the signal-to-noise ratio at the receiver decreases with distance. Combined, these mean that the farther one is from the access point, the more difficult it is for the receiver to decode the data.

The 802.11 standards have a way to deal with that. As the AP ( access point) detects a receiver with a weaker signal, it reduces the data rate, minimizing the effects of attenuation (actually free space path loss) and noise. At some distance, the signal will be too weak for data transfer. We discuss this, along with more details of Wi-Fi operation in Learning Tree’s Course 450 Introduction to Networking.

Getting a stronger signal

The goal of a range extender is to receive the data from the access point and to resend it to the mobile device, then to receive the data from the mobile device and relay it to the AP. Then the AP thinks it’s close to the device and can use a higher data rate.

That sounds good except for the kicker: many inexpensive range extenders only have a single radio. That means they can send or receive only on a single channel. So when they resend the AP data to the remote client, they are using the same channel the AP is! That means the channel is twice as busy as before. The busier channel reduces the overall throughput on the channel leading to an effective reduction the user experience.

A better range extender

More expensive range extenders have two or more radios. That means that they can receive on, say, channel 1 and resend to the mobile device on channel 6. This is a much better solution for small networks. It means the signals won’t interfere and the data rate can still be high. But as larger networks move to access points using three channels simultaneously, the range extender becomes impractical. It’s still great for a home or small office, but not a solution for larger installations.

An additional access point is even better

Adding an additional access point is an even better solution. It can have multiple radios or not based on need. It can use a separate channel than the initial access point. In a more complex environment, one can even take advantage of “tri-band” devices.

The downside of adding an additional AP is that it requires a network connection. This can be Ethernet, or in a home or small office, it can be connected using data over the powerlines. I use the latter. In some installations, additional access points are powered over the network cable using power over Ethernet, so a connection to wall current isn’t necessary.A Wireless Access Point

Should I get a range extender or not?

If you have a small network with few users, a single-channel range extender may fit your needs. If you have a larger network or more than one or two users, I strongly recommend a dual- or multi-radio extender. Since those multi-radio extenders are more expensive than the single-radio ones, it may not be much more costly to get an access point. In fact, dual-frequency (2.4 and 5GHz) refurbished 802.11ac access points are sometimes offered for under $20. In that case I recommend a new router.

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