WiFi Interference

Document created by shaw-jamess on Nov 27, 2013Last modified by shaw-alexander on Dec 3, 2018
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Understanding WiFi Issues

WiFi allows an access point, like a modem or router, to share an Internet connection with client devices like computers, tablets, phones, and many other wireless-capable devices. Much like a cordless phone, the access point is the base station and your wireless device is the handset, capable of connecting to the network without wires providing it is within range of the base station.




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What is WiFi?

WiFi, which stands for Wireless Fidelity, is one of the ways we connect to the internet. Using radio signals, multiple devices such as computers, smart phones, game consoles, and more are able to connect to the internet without being tethered via Ethernet cable, allowing freedom to connect when and where we want.

Your Shaw modem acts as a wireless hub, transmitting radio signals to your devices which can also transmit the radio signals back to the modem, thus establishing back and forth communication, as well as a wireless network. Because the connection relies on transmission from the modem to the device, WiFi signal is always strongest when standing within line of sight of the modem with no obstructions.

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Possible Causes of Physical Interference

WiFi devices let you access your network using a wireless connection from anywhere within the operating range of your wireless network. However, the number, thickness and location of walls, ceilings, or other objects that the wireless signals must pass through, may limit the range. Typical ranges vary depending on the types of materials present in the home, as well as other nearby objects that may cause interference. You can minimize risk of interference by ensuring line of sight to your modem, or by reducing the number of walls or floors between the connected device and the modem.


  • Brick, stone, and concrete walls - While not usually capable of blocking a WiFi signal, heavy stone, concrete, and brick will limit the effectiveness of a wireless signal.
  • Walls and wall construction - Interior walls are generally not a large hindrance to WiFi signals when there is no insulation, metal ducting, metal pipes, and steel studs are being used.
  • Metal - The metal in walls or ceilings can have a dramatic effect on the range of a wireless network. This is why modem will offer the best connection to devices on the same floor of your home. Floors and ceilings often have metal, wiring, conduits, ducting, and thermal shielding that can disrupt the radio signals that form your wireless network.
  • Floors - Having a wireless signal from a different floor will definitely impact WiFi signal. In addition tiling, carpeting and hardwood flooring may cause WiFi interference.
  • Glass - Glass from windows and mirrors can decrease the range of your WiFi signal, as they reflect the signal back around the room unpredictably.
  • Lead paint - While uncommon, lead paint acts as a very effective shield for radio signals and can diminish or block a local WiFi network.


WiFi signal in house

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Possible Causes of 2.4 Ghz WiFi Interference

The list of items that may cause WiFi interference is surprisingly long, as the 2.4 GHz space is unlicensed and free to use for any wireless connection. Interference can be caused not only by other nearby wireless networks but also any 2.4 GHz operating devices, and even high voltage devices that generate electromagnetic interference.

Please see the list below for some examples of devices that can cause interference.


Bluetooth DevicesBluetooth devices such as headphones and speakers operate in the same 2.4 GHz space as WiFi, meaning they may cause interference. Newer models of Bluetooth devices are usually built to avoid active WiFi channels.
Nearby Wireless NetworksYour neighbours likely all have wireless networks and any that operate on the same frequency will be causing interference and disrupting the performance of your local network.
Cordless PhonesMany cordless phones operate on the same 2.4 GHz space as WiFi networks. If your network performance drops whenever your cordless phone is in use, consider switching to phones that operate on a different frequency.
Baby MonitorsJust like cordless phones, most baby monitors operate on 2.4 GHz and, given the constant connection between the monitor and the receiver, a baby monitor can affect the performance of your network.
MicrowavesOlder or poorly-shielded microwaves cause a great deal of electromagnetic interference in the 2.4 GHz space, causing transmission problems for many wireless devices. Newer and modern microwaves are properly shielded and should not present any considerable problems.
Wireless Security EquipmentWireless cameras and motion sensors operate just like baby monitors and will congest 2.4 GHz networks. The latest generation of this type of equipment has the ability to connect to your modem (cameras and sensors are WiFi-ready) and will operate on your WiFi network to avoid causing interference.
RadiosRadios and police scanners operate on a wide range of frequencies and can cause interference to any other nearby radio device. Proximity is likely the deciding factor in radio interference so don't have your modem located directly next to (or on) a radio transmitting device.
Monitors, TVs and ScreensMonitors and TVs, especially those that are not properly shielded, can cause interference for 2.4 GHz networks (specifically channels 11-14). Don't place your access point directly next to (or on) a TV, monitor, or screen.

High-Voltage Household Appliances

High voltage or high-draw household items like laundry machines and air conditioning units cause electromagnetic interference. If you notice degraded network performance while operating a household appliance then your access point may be too close, or the appliance may not offer proper electromagnetic shielding.

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Environmental Factors

Apart from specific local devices causing radio interference on the same frequencies as your WiFi network, there are some environmental factors that can inhibit or disrupt the functioning of your home WiFi network.

These factors include:

  • Additional Electronics - Wires, unprotected cables, and other large electronic devices like televisions can physically block WiFi signals.
  • Large Appliances - Fridges, stoves, washers, and dryers can all block a WiFi signal.
  • Large Furniture - Heavy furniture such as bookshelves, mirrors, and fish tanks can all block WiFi signals.
  • Aquariums - Similarly to windows and mirrors, the glass from aquariums reflects WiFi signals.

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Possible Remedies

While most of the interference experienced by your home network may be unavoidable (neighbour's networks, domicile construction, etc.), there are some possible remedies of which to be aware when attempting to improve the performance of your home network:


  1. Make use of the 5 GHz WiFi frequency whenever possible. The 5 GHz range is still a newer frequency, so it is less used in many congested areas, and typically provides faster speeds as it is capable of carrying more data between your devices and the Shaw modem.
  2. Allow your modem to automatically manage wireless channels to switch away from congested frequencies. While forcing your modem onto a fixed channel can be quite effective in some situations, your Shaw modem has the ability to automatically move to a different channel if the current channel is experiencing too much interference.
  3. Line of sight works best for signal strength. For example, you shouldn't put your modem on the floor as this wastes half of its 360 degree field of range (see image below).

best place to put your wireless access point at home


    1. Use WiFi devices whenever possible. Some home wireless devices like baby monitors and security equipment use their own point-to-point connections and can cause a great deal of interference to other local wireless networks. By using WiFi devices, all clients connect to the signal and network provided by your access point.

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Ideal WiFi Operating Range and Throughput

WiFi ranges are always going to vary due to circumstances outside of our control, and therefore range is never guaranteed. The best signal will be available within line of sight of your modem, and will degrade from there with distance and obstructions.

However, in a laboratory setting with no walls or interference, the ideal standardized performance from a modem to a single device would be:


DeviceData Rate
Approximate Range
Devices that can only connect to 2.4 GHz54Mbps100-200ft
Devices that can connect to 2.4 GHz or 5 GHz54Mbps or higher80ft
Devices that connect primarily to 5 GHz430Mbps or higher80ft or more


While later generations of WiFi technology offered a greater amount of bandwidth, their operating range decreased as more power gets used to enable said bandwidth, resulting in less range. This is why a single modem cannot provide adequate coverage for a large home, or in other areas around the home such as a yard or garage.

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What is 802.11ac?

The latest WiFi Protocol, 802.11ac, operates exclusively on 5 GHz and should experience much less interference, as the 5 GHz space is less congested. Furthermore, 802.11ac offers beamforming in which the signal from the router is focused towards the client connection (unlike the above diagram where the signal is a 360-degree bubble from the access point).


To access the enhanced speed, range, and features like beamforming, you must be using not only an 802.11ac access point, but also 802.11ac clients. As 802.11ac is still a newly certified standard it is not built into most devices on the market today. Over time, 802.11ac access points will drop in cost and the technology will become the default in client devices.

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