Troubleshooting wireless networks

If your wireless network is experiencing connectivity or stability issues, you can use WiFi Explorer to identify the causes and determine possible solutions after considering each of the cases described below.

- In all cases, please refer to your access point's or wireless router's User Manual for instructions on how to make changes to the configuration of your wireless network, if required.

Band

The built-in Wi-Fi card in modern Mac computers can operate on two different frequency bands: 2.4 GHz and 5 GHz.

Band | 2.4 GHz | 5 GHz
Channel | 3 non-overlapping channels | 23 non-overlapping channels
| Mode | B, G, and N | A, N and AC
Network Range | Wider range | Shorter range
| Interference | Higher | Lesser

Modern wireless routers and access points support dual operation in these two frequency bands, but older models, as well as older wireless clients such as iPhone 4 and 4S only run in 2.4 GHz.

If you are troubleshooting or setting up a new wireless network, make sure which frequency bands are supported by the different wireless devices to ensure they can connect to the network using the frequency of your choice.

Range

The 5 GHz band has a shorter range because in radio frequencies, the higher the frequency the shorter the range.

If you are deploying or troubleshooting a network in the 5 GHz band, keep in mind that the distance it will cover will be smaller than the distance of a 2.4 GHz wireless network.

Interference

In wireless communications, the transmitted signals of co-existing or adjacent channels will overlap and interfere with each other, resulting in poor signal quality. Signals may generate from nearby networks in the same frequency band or from externals sources such as video baby monitors, cordless phones, microwaves ovens, etc.

The 2.4 GHz band has only three non-overlapping, 20 MHz-wide channels. These channels are 1, 6, and 11. As a consequence, the presence of multiple 2.4 GHz access points and clients will have a great impact in the performance of your wireless network and may result in degraded throughput and added latency. If you are using the 2.4 GHz band, it is important that you choose the less congested, non-overlapping channel for your network.

Networks in the 5 GHz have better performance and are less impacted by interference because most of the wireless devices such as video baby monitors, cordless phones, microwave ovens, and Bluetooth devices transmit in the 2.4 GHz frequency range. There are also many fewer wireless clients in the 5 GHz band and plenty of 20 MHz-wide non-overlapping channels.

If your wireless network is experiencing connectivity and stability issues, make sure you choose the less crowded, non-overlapping channel available. Also consider using a 5 GHz configuration if your access point and wireless clients support it.

- To quickly check for conflicting or overlapping channels, select the Spectrum view in WiFi Explorer.

Signal Quality

You can determine the signal quality of your wireless connection by monitoring the signal-to-noise ratio (SNR) of the wireless network. This metric compares the signal strength to the background noise levels to offer a more accurate estimation of the quality of the connection.

- To monitor the SNR of the wireless network, select a wireless network from the list, switch to the Network Details tab, and then choose SNR.

If your wireless network is experiencing connectivity and stability issues, make sure SNR is above 25 dB.

- If SNR is lower than 25 dB and signal strength is below 40% (-70 dBm), then you may need to move closer and remove any possible obstructions between your computer and the router to see if the signal level increases.
- If SNR is lower than 25 dB and noise is above 10% (-90 dBm), then you may need to check any active electronics nearby the computer or the router, and make sure they are turned off or disconnected to see if the noise level decreases.

Channel Width

In the 802.11n wireless standard, channel bonding allows for using two 20 MHz-wide channels simultaneously for higher data rates. This configuration renders a channel width of 40 MHz: 20 MHz from a primary channel plus 20 MHz from a secondary channel that is below (ch,-1) or above (ch,+1) the primary channel.

Although possible in some configurations, enabling channel bonding on a 2.4 GHz can significantly increase the chance of interference because you can only create one non-overlapping 40 MHz channel.

If your wireless network in the 2.4 GHz band is experiencing connectivity and stability issues, make sure you use only 20 MHz-wide channels if you live in an area where there are a lot of 2.4 GHz wireless networks.

- To check the channel width, select a wireless network from the list and switch to the Network Details view in WiFi Explorer.

In 802.11ac networks, channels can have a channel width of 80 or 160 MHz, and because operation of 802.11ac is limited to the 5 GHz band, co-channel interference with 2.4 GHz is not possible. You should, however, exercise care when selecting the primary channel for your 802.11ac network if other nearby 802.11a, n or ac networks are present, as co-channel interference is still possible between them.
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