5 Ways WiFi Interference Can Hurt Your VoIP Call Quality

If your business relies on a cloud phone system like Telzio to handle calls, connectivity is everything. While a wired ethernet connection will always be the most reliable option for IP phones, wireless setups are sometimes unavoidable. When that's the case, knowing what causes interference and how to reduce it can be the difference between crystal-clear calls and dropped conversations.

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Physical Obstructions

When thinking about WiFi, it's important to remember what that signal actually is. For all intents and purposes, WiFi is nothing more and nothing less than a very specific type of radio signal. This means that it is vulnerable to the same sorts of interference as the AM/FM radio in your car. Much of that interference results from physical materials standing between the source of the wireless transmission and its intended target.

If you mentally draw a straight line from your laptop or WiFi-enabled IP phone to the wireless router providing it with service, consider what you're asking that line to pass through.

Different materials will cause different levels of interference. Concrete, metal, and stone will stop almost any wireless signal from penetrating them. Glass will refract signal, causing it to appear strong but delivering slow speeds. Wood's resistance to wireless signals can be estimated based on the relative strength of the wood. Flimsy woods like balsa and composite-wood materials will have little to no interference. Hardwoods like cherry, oak, or mahogany will soak up wireless signals like a sponge.

You can easily see how the walls (made of studs and drywall) do little to interfere with WiFi transmissions. The problem comes when objects made of radio-impermeable materials get in the way.

Channel Congestion

If your office is in a building with multiple tenants, or your office is large enough that it requires multiple wireless routers to cover it, you may be running into issues with channel congestion.

There are 13 available channels in use for WiFi transmissions. The more signals utilizing a single channel, the poorer their performance will be. Most routers automatically scan their environment every 24 hours to see which channels have the fewest networks on them, but this isn't always reliable. Third-party tools like Channelyzer or WiFi Analyzer for Android let you actively monitor your environment and pinpoint which part of the spectrum is least congested.

In this example, you can see the strongest (and likely closest) signal is on Channel 1 by itself. There are three separate networks competing on Channel 6, and one network using Channel 11. Ideally, two of the three networks on Channel 6 would be moved to different channels by changing the setting on the wireless router itself.

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Frequency Allocation (2.4 vs 5 GHz)

Most modern routers broadcast on two primary frequencies: 2.4 GHz and 5 GHz. Each has its trade-offs. The 2.4 GHz band offers longer range and better wall penetration, but slower speeds. The 5 GHz band is faster, but shorter in range and more sensitive to interference. Wi-Fi 6 routers now handle both bands more efficiently, but the principle still applies when configuring older hardware.

Since most VoIP calls require no more than 100 kbps for high-quality, stable voice, 2.4 GHz is generally the safer choice for business phones. Reserve 5 GHz for devices that need higher bandwidth, like video conferencing or file transfers.

Environmental Interference

Beyond the seemingly obvious physical factors (most people understand that placing their wireless router inside an aluminum box is a bad idea), there are more than a few oddball things which can generate interference that limits your wireless effectiveness for VoIP.

Most especially, you want to keep in mind the presence and proximity of high-powered electronic devices to your wireless router. Depending on the age of a given device, as well as the quality of its shielding, it can generate a significant electromagnetic (EM) field. EM fields, when strong enough, can essentially block wireless routers from establishing a stable connection with other devices. The field scatters the radio wave of the wireless router when it gets close. Unfortunately, it can be hard to figure out whether or not a device is generating such a field.

Apps like Toolbox use your smartphone's built-in magnetometer to detect localized EM field strength, giving you a quick and reliable reading. There's also the old field tech trick of rubbing your arm hair and holding it near a device to check for static, though the app is the more reliable option.

Protocol Conflicts

Finally, let's address one of the lesser-known issues afflicting wireless connections: Standards.

Wireless protocols have evolved significantly over the past two decades, from 802.11a/b/g/n/ac to today's Wi-Fi 6 and Wi-Fi 6E standards. Each generation brought faster speeds and better reliability, but the core challenge remains: older devices can only communicate using older protocols, and a network can only move as fast as its least capable device.

The issue arises from using older hardware in conjunction with newer hardware. With a few exceptions, it is nearly impossible to force an older wireless antenna to utilize a newer wireless protocol. This means that a device purchased when 802.11n was the gold standard will only ever be able to use that protocol.

Since an antenna can only use one protocol at a time, when a user connects an older device to a wireless network, that network has to use whichever protocol is usable by all devices on the network. In other words, you could have four brand-new smartphones capable of Wi-Fi 6 connected to your network and running perfectly.

The moment someone connects an older device to your office network, every other device may be forced to drop down to match that device's protocol. One legacy laptop or tablet can slow down an entire network.

Luckily, as we discussed earlier, most routers are capable of broadcasting two separate networks split between 2.4 and 5 GHz. The best solution to old hardware slowing down the rest of your network is simply to park any old devices on the slower of the two available networks, and save your higher speeds for the devices which need them.

While this list is certainly not comprehensive, it should have armed you with some new weapons in your battle for reliability and stability on the part of your VoIP service. Remember, the best solution when it comes to using WiFi for VoIP is almost always "don't", but if you do, try to keep these things in mind as you move through your troubleshooting process.

Ready to get better call quality on a reliable cloud phone system? Contact Telzio and we'll help you find the right setup for your business.

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