How to troubleshoot Wi-Fi Interference with NetSpot

How to Fix WiFi Interference: Step-by-Step

Most users aren’t looking for theory — they just want a clear solution. Here’s how to get started:

Step 1: Scan the Environment with a WiFi Interference Scanner

The first step to solving any WiFi issue is to detect it properly. You can’t fix what you can’t see. That’s where a WiFi interference scanner comes in. Use a dedicated app to scan your wireless environment and see exactly what’s going on with both your network and surrounding ones.

Tools like NetSpot let you visualize:

• Signal-to-noise ratio (SNR)
• Overlapping channels
• Channel utilization
• PHY mode and band usage

NetSpot displays this information in real time using clear signal graphs, channel overlap charts and build WiFi heatmaps. It supports 6 GHz scanning and detects hidden networks, making it ideal for troubleshooting interference in modern networks. Once you see the full picture, it becomes much easier to decide which interference-mitigation steps to take next.

Step 3: Take Action Based on the Cause

Now that you’ve identified what’s interfering with your WiFi, here’s how to respond:

Positioning of a Wireless Router

If the problem is weak Wi-Fi in certain rooms, start with the router’s location. Obviously the way you position your wireless router will have effect on your coverage area and WiFi signal strength. Incorrect placement can lead to weak signals, dead zones, and slow network speeds.

How to troubleshoot :

• Position your wireless router in the middle of the space where the network is needed. If the router is placed off-center, the signal won't be even, leaving some areas with poor coverage.
• Ensure the router antenna is vertical. While many antennas can be adjusted, a straight-up position typically provides the best performance. For routers with multiple antennas, angling them differently, such as one vertical and one diagonal, can enhance signal coverage.
• Place your router on an elevated surface. A desk or shelf will provide better reception compared to placing it on the floor. Avoid positioning it near electronic devices like microwaves or cordless phones, as well as metal objects or mirrors, which can cause radio frequency interference.
• If you have multiple floors, position your wireless router on a higher floor. This helps the signal radiate downward more effectively, improving coverage across all levels.

Real-world example: Wi-Fi heatmap after relocating the router — areas with poor signal (green/blue) became much stronger (red), just by moving the router to a better spot.

To get the most out of your Wi-Fi setup, use tools like NetSpot to analyze your network and create a heatmap. This allows you to visualize signal strength and make data-driven adjustments to position your wireless router optimally.

Physical obstacles

The construction of a building, whether it’s a home or office, significantly affects the range and speed of wireless communication. One of the main WiFi interference causes is the presence of physical obstacles that weaken or block the radio waves used by Wi-Fi. Understanding what interferes with WiFi is critical for optimizing your network’s performance.

Different materials have varying levels of impact on Wi-Fi signals. While wood and glass cause minimal disruption, materials like concrete, brick, and metal can drastically degrade signal quality and lead to slow network speeds.

How to troubleshoot :

If you suspect physical obstacles are causing wireless interference, there are a few simple steps you can take to improve signal strength:

• Relocate the Wireless Device: Even moving a Wi-Fi routers or device a few feet can have a noticeable impact on signal quality. Adjusting the antenna direction can also help reduce WiFi interference.

• Add a Wi-Fi extender : For spaces where physical obstacles cannot be avoided, a Wi-Fi extender can re-transmit the signal, ensuring better coverage even in remote areas. This is particularly useful for overcoming WiFi signal interference caused by thick walls or multiple floors.

• Consider Powerline Adapters: In larger spaces with challenging layouts, Powerline adapters use your existing electrical wiring to extend the network. Pairing them with a Wi-Fi extender provides a reliable solution for areas with high wireless interference.

Overlapping channels

Many devices, even those not directly connected to your WiFi network, can cause frequency interference by operating on the same 2.4 GHz, 5 GHz оr even 6 GHz spectrum. This interference disrupts the radio waves your WiFi depends on, meaning the network may be slower or disconnect, resulting in frustratingly poor performance. Recognizing what causes WiFi interference and addressing it is key to maintaining a reliable connection.

To help you identify and address what interferes with WiFi, here’s a detailed table showing the most common interference sources, their impact on your network, and practical solutions:

Use your WiFi interference scanner to see which of these is the least crowded in your area right now.

How to troubleshoot :

• If the problem is overlapping channels, pick another channel.
• If the problem is non-WiFi interference from household devices, switch to 5 GHz or 6 GHz, where those devices don’t operate.
• If the problem is signal loss after walls, switch the client in that room to 2.4 GHz (better penetration) or extend the network with a mesh/AP.
• If the problem is evening congestion, open the scanner again and move to a channel that is currently cleaner. Some routers can do this automatically.
• If your router supports it, enable smart/dynamic channel selection so it can react to changing interference levels without you.
• If you’re in a crowded apartment building and use wide channels, try narrowing the channel width from 40 MHz down to 20 MHz to reduce adjacent-channel interference.
• If it stays slow right next to the router, run an ISP speed test (wired if possible), reboot the router, and check for firmware updates.

Real-world example: many users never check what channel their access point is using and just leave the factory settings. In the “before” situation you can see almost all networks sitting in the same part of the 2.4 GHz band and overlapping each other, while a couple of channels on the right stay free. After switching the AP to one of these unused channels, the network moves out of the crowded area and the interference drops. In simple cases, changing the channel to a free one is enough to fix unstable WiFi.

How to Pick the Right WiFi Channel (Even If You’re Not Sure):

If you're not sure which WiFi channel to pick, here's a simple way to figure it out. There are three types of channel overlap, and each affects your network differently:

1. No Overlap (best case): Networks use completely separate channels, resulting in no interference and optimal performance.

2. Full Overlap (not ideal, but manageable): Networks use the same channel but can negotiate access due to Wi-Fi's collision avoidance protocols, minimizing interference compared to partial overlap.

3. Partial Overlap (worst case): Networks use adjacent channels, which creates significant interference as signals are seen as noise by each other.

The NetSpot Android app includes a built-in Best Channel Recommendation feature. It automatically analyzes nearby networks and tells you which channel is optimal — perfect if you're not sure how to read channel graphs.

Conclusion

Whether you’re in a crowded city apartment or a multi-level house, WiFi interference can ruin your experience. A WiFi interference scanner like NetSpot gives you the power to not just detect problems, but fix them. As WiFi 6E and 7 become standard, now’s the time to take control of your network’s environment and build a future-proof wireless setup.

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