As more clients expect seamless connectivity in every part of a building, Wi-Fi has become as critical as power and lighting. Rob Shepherd explores how new testing tools and smarter commissioning methods are helping electrical contractors diagnose dead zones, dropouts and interference.
As commercial spaces fill with connected devices, clients now expect flawless Wi-Fi everywhere – from the basement plant room to the top floor meeting suite. For electrical contractors, that expectation often lands squarely on their shoulders but the problem is that Wi-Fi networks behave nothing like fixed wiring. Radio signals bounce, fade and interfere with one another, and when coverage dips or devices drop off, it’s often up to the contractor to figure out the root cause of the problem.
Problem solving
Could it be possible that solving common Wi-Fi problems is not that difficult after all? With the right tools and a little knowledge, finding the root cause of the most common Wi-Fi network issues can be quick and simple.
The simplest way to confirm whether there’s an issue with the Wi-Fi network is to use a tool that can test both connectivity and backend service performance. Start by using a known working device to check authentication and connectivity, then test key network services such as DHCP, DNS and gateway availability and performance to determine where to focus troubleshooting efforts. Additionally, running throughput tests on both wired and wireless connections can help identify any discrepancies and should always be part of any process.
After ruling out problems with network services and proving that the issue reported is indeed on the Wi-Fi network, it is time to find the ultimate cause of the issue. Some of the most common causes for connectivity, roaming and slow speed problems on Wi-Fi are:
Signal coverage
Poor coverage is one of the most common causes of Wi-Fi connection issues. It stands to reason that if Wi-Fi devices can’t detect each other, communication won’t happen.
While many Wi-Fi troubleshooting tools can measure the signal strength of access points (APs), the most effective way to identify coverage gaps is to perform a site survey. This makes it possible to visualise network coverage throughout the area and pinpoint problem spots. Coverage issues are usually resolved by adding more APs, using higher gain antennas or increasing the transmitting power of existing APs. However, boosting transmitting power also raises noise levels, so it’s generally preferable to improve coverage by installing additional APs or upgrading antennas.
Adjacent channel interference (ACI)
ACI occurs when transmissions on nearby channels overlap, causing one channel’s signals to interfere with another’s. To identify ACI issues, examine all APs in each area and ensure that each operates on non-overlapping channels. The most efficient approach, however, is to use a site survey tool that automatically detects and highlights interference zones on a floorplan.
To fix ACI problems, make sure APs with overlapping coverage areas are configured to use completely non-overlapping channels. While many modern AP controllers handle this automatically, the recommended best practice is to use a Wi-Fi design tool to calculate optimal channel assignments before deploying the network.
Signal to noise ratio (SNR)
The quality and speed of a Wi-Fi connection are directly influenced by the SNR detected by both APs and client devices, yet very few test tools on the market can accurately measure SNR. The most effective approach is to use a purpose-built test tool designed with SNR measurement capabilities. Issues with low SNR can often be resolved by enhancing Wi-Fi coverage or eliminating sources of interference such as non-IEEE 802.11 devices that raise the noise level in the environment.
Non-IEEE 802.11 interference
Wi-Fi networks often share their frequency bands with other radio technologies. Devices such as Bluetooth/BLE peripherals, cordless phones, ZigBee devices, wireless security cameras and even microwave ovens can all cause interference.
Although Wi-Fi systems are designed to tolerate some external noise, these non-IEEE 802.11 transmissions do not follow the same rules of airtime sharing and can significantly impact performance. The best way to identify such interference is by using a spectrum analyser, preferably one capable of automatically detecting and classifying interference sources. To resolve these issues, remove or disable the interfering device if possible, or change the Wi-Fi channels used by the APs. Many AP controllers can adjust channels automatically to mitigate interference.
Co-channel interference (CCI)
A common cause of slow Wi-Fi performance is CCI, which occurs when multiple APs operate on the same channel. It is possible to detect CCI by analysing all active APs in an area and verifying that they are using different channels. The most effective approach is to use a site survey tool that visually highlights areas affected by channel overlap on a floorplan.
To reduce CCI, limit the number of APs operating on the same channel. Although many modern AP controllers can manage channel assignments automatically, it’s best practice to use a Wi-Fi design tool to plan and optimise channel allocation before deploying the network.
Network authentication
Managing authentication and encryption can be challenging, with problems such as incorrect passphrases, missing certificates, client device limitations and misconfigurations preventing Wi-Fi connection.
Wi-Fi authentication can be verified by using a test tool that simulates client devices. Such tools should support all modern authentication and encryption methods and allow media access control (MAC) address spoofing to confirm that access control lists are functioning correctly. Once an authentication issue is identified, resolving it typically involves verifying and correcting configurations on the client device, wireless network or authentication server.
Sending the right signals
Wi-Fi network issues don’t have to be complicated for electrical contractors to troubleshoot or fix. With the right diagnostic tools and a clear understanding of network behaviour, it is possible to identify whether a problem lies within the Wi-Fi signal or the wired backhaul, while proper visibility into the network allows for faster detection of performance bottlenecks, interference or configuration errors. Equipped with the right knowledge and resources, electrical contractors can efficiently locate the cause of connectivity issues, deliver reliable solutions for clients and ensure smooth, high performance Wi-Fi operation.
Contributors
Rob Shepherd (author)
Rob is Consulting Editor for InstallerELECTRIC. He is a well-respected journalist with a strong history in the electrical sector.
