How to Properly Test a Wi-Fi Network: From Speed ​​to Interference

High-quality Wi-Fi is the foundation for comfortable work, learning, and entertainment. But even modern routers with Wi-Fi 6 support may slow down, "lose" devices, or deliver speeds lower than advertised. The problem isn't always the hardware: the culprit could be congested channels, interference from neighboring networks, outdated firmware, or even improper router placement. In this article, we'll look at how comprehensively test the Wi-Fi network — from basic speed testing to radio frequency background analysis.

You'll learn which tools to use (including free ones), how to interpret test results, and what to look for when diagnosing problems. This material will be useful for both novice users and those looking to optimize their network for multi-user workloads (4K streaming, online gaming, smart home)All methods have been tested on routers. ASUS RT-AX88U, TP-Link Archer C6 And Keenetic Giga with the latest firmware.

1. Internet Speed ​​Test: What and How to Test

The first step is to measure real speed connection. But there are some nuances here: tests on different services can show different results, and the speed over a cable and Wi-Fi often differs by 2-3 times. Use Speedtest.net, Fast.com (from Netflix) or nPerf - they provide the most objective data.

It is important to test speed in different scenarios:

• 📱 On a smartphone (Android/iOS) next to the router and in the far corner of the apartment
• 💻 On a laptop/PC via Wi-Fi and via Ethernet cable (for comparison)
• 🎮 On the gaming console (PS5, Xbox) or Smart TV if they are connected wirelessly

Please note ping (delay) and jitter (ping variability) - these parameters are critical for online games and video calls. If the ping is higher 50 ms or jumps from 20 ms to 200 ms, the problem may be a congested channel or interference.

⚠️ Attention: If the speed via Wi-Fi is lower than via cable by more than 50%, check connection standard in the router settings. Outdated 802.11n (Wi-Fi 4) limits speed to 150-300 Mbps, even if the provider's tariff is 1 Gbps.

2. Wi-Fi coverage analysis: dead spots

Weak signal in some rooms is one of the most common problems. To diagnose it, use coverage mapsApplications like NetSpot (Windows/macOS) or WiFi Analyzer (Android) builds a heat map of the signal, showing where it weakens.

How to draw a map correctly:

1. Upload a floor plan of your apartment/office (or draw a diagram by hand).
2. Walk through all the rooms, noting the signal level (dBm) at key points.
3. Please note -60 dBm and above is an excellent signal, -70 dBm - acceptable, but -80 dBm and below is the problem.

Typical signal "jammers": concrete walls, metal doors, aquariums, microwaves and even mirrors with a metallic coatingIf the signal disappears completely in some area, try moving the router or installing repeater.

Turn off all devices except the test device | Check the signal at 5+ points in the apartment | Record the values ​​in dBm | Compare with the reference values ​​(-60 dBm is excellent) | Repeat the test at frequencies of 2.4 GHz and 5 GHz -->

3. Interference diagnostics and optimal channel selection

Wi-Fi works on radio frequencies, which may be overloaded by neighboring networks. At the frequency 2.4 GHz total 3 non-intersecting channels (1, 6, 11), and on 5 GHz There are more of them, but the signal penetrates walls worse. To analyze interference, use:

• 🖥️ WiFi Analyzer (Android) - shows channel load in real time
• 🍎 AirPort Utility (iOS) - a built-in tool for Apple users
• 🪟 inSSIDer (Windows/macOS) - Professional analyzer with standards-based detail

The ideal channel is the one where less than 3-4 active networks with signal strength below -75 dBmIf all channels are on 2.4 GHz busy, switch to 5 GHz (if your router and devices support it). In the router settings (Wireless → Channel) select the channel manually - automatic selection often makes mistakes.

⚠️ Attention: In apartment buildings, channels 2.4 GHz are often overloaded due to the large number of routers. If your router supports 5 GHz, but devices (for example, Xiaomi smart light bulbs) work only on 2.4 GHz, consider the option with separation of networks (different SSID for each frequency).

4. Testing connection stability: ping and packet loss

Slow speed isn't always the main problem. It's much worse when the connection unstable: YouTube videos are lagging, voices are interrupted in Zoom, and online games are laggy. To diagnose this, use long ping test:

On Windows:

ping -n 100 ya.ru

On macOS/Linux:

ping -c 100 ya.ru

Analyze:

• 📉 Packet loss: if more 1-2% - problem with signal or router.
• 🕒 Ping variability: if the spread is from 10 ms to 300 ms — there is interference.
• 🔄 Response time: stable ping 10-30 ms — the norm for a home network.

If packet loss is high, try:

1. Reconnect the device to Wi-Fi.
2. Reboot the router (turn it off) 30 seconds).
3. Disable Qos or Band Steering in the router settings (sometimes they conflict with devices).

5. Checking the router load: who's hogging the traffic?

If the network is slow, it may be overloaded by one of the devices. For example, torrent client, updated Windows or IP camera, which constantly streams video to the cloud. To find the "culprit":

Log into your router's web interface (usually at 192.168.1.1 or 192.168.0.1) and find the section:

• 📊 Traffic Monitor (ASUS)
• 📈 Bandwidth Control (TP-Link)
• 🖧 Devices → Statistics (Keenetic)

Please note devices with:

• 🔴 Constantly high traffic (for example, > 50 Mbps in the background).
• 🟡 Suspicious connections (unknown IP or MAC addresses).
• 🟢 Abnormal ping (if the router shows delays for a specific device).

If you find a device that is consuming too much data, limit its speed in the settings. QoS or disconnect from the network during the tests. Also check the router for unauthorized connections — Perhaps your neighbors have connected to your network.

How to block other people's devices on the network?

Find the section in your router settings Wireless → MAC Filter and blacklist the MAC addresses of unknown devices. Alternatively, change your Wi-Fi password to a more complex one (for example, WPA3-Personal with 12+ characters).

6. Testing DNS and connection issues

Sometimes the problem is not with Wi-Fi, but with DNS serversSymptoms: Websites don't open, but Skype or Telegram work, or speed in Speedtest It's high, but the pages take a long time to load. To check:

Change the DNS on your device or in your router settings (DHCP → DNS Server). Try:

• 🌍 8.8.8.8 And 8.8.4.4 (Google DNS)
• 🛡️ 1.1.1.1 And 1.0.0.1 (Cloudflare)
• 🇷🇺 77.88.8.8 And 77.88.8.1 (Yandex DNS)

To check DNS speed use DNS Benchmark (Windows) or command:

nslookup ya.ru 8.8.8.8

Compare response times (Query time) for different DNS. If the difference is greater 100 ms, change the server.

Also check if your router is blocking access to certain resources. In the settings (Firewall or Parental Control) filtering by can be enabled URL or IP.

7. Advanced diagnostics: router logs and specialized utilities

If basic tests do not reveal any problems, but the network is still unstable, please contact router logsThey contain information about connection errors, connection resets, and IP conflicts. Logs are typically located in:

• 📄 Administration → System Log (ASUS/TP-Link)
• 📜 System → Journal (Keenetic)

Look for recurring errors, such as:

• 🔌 DHCP lease failed — problems with IP address distribution.
• 📡 Authentication failed — the device cannot connect due to an incorrect password.
• 🔄 WAN connection lost — connection breaks with the provider.

For in-depth analysis use PRTG Network Monitor or Zabbix — they allow you to monitor your network in real time, track channel load, and identify bottlenecks. These tools are more suitable for offices, but their free versions are also available for home users.

⚠️ Attention: If the error appears frequently in the logs Kernel: br0: received packet with own address as source address, this may indicate loop in the network (For example, if two routers are connected to each other via a LAN port, not a WAN port.) In this case, check the physical cable connections.

FAQ: Answers to Frequently Asked Questions

Why is Wi-Fi speed slower than cable?

This is normal: Wi-Fi is always slower due to interference, limitations of the standard (for example, 802.11ac vs 802.11ax) and losses during data transmission over the air. The difference is 20-50% - standard, but if it exceeds 70%, check the router settings (mode 80 MHz for 5 GHz, included MU-MIMO) and update the firmware.

How do I know which Wi-Fi standard my device supports?

On Windows: Open Device Manager → Network Adapters and find the Wi-Fi module model. Then search for its specifications on Google. On Android/iOS: go to Wi-Fi settings, connect to the network, and view connection information (e.g. Speed: 866 Mbps points to 802.11ac).

Is it possible to increase the Wi-Fi range without a repeater?

Yes, there are several ways:

1. Move the router to the center of the apartment/office.
2. Replace standard antennas with more powerful ones (for example, TP-Link TL-ANT2408CL).
3. Set up Transmit Power to maximum (in some routers this is 100% or 20 dBm).
4. Use 2.4 GHz instead of 5 GHz (the signal travels further, but more slowly).

What to do if Wi-Fi turns off at night?

Possible reasons:

• 🕒 Energy saving: the mode may be enabled in the router settings Schedule (scheduled shutdown).
• 🔌 Nutritional problems: The router's power supply is overheating or faulty.
• 📡 Automatic update: Some routers reboot to install firmware.

Check your settings System → Reboot Schedule and the temperature of the router (it should not exceed 60°C).

How to test Wi-Fi on smart devices (lamps, sockets, cameras)?

Smart devices often only work on 2.4 GHz and don't have a testing interface. To check the stability of their connection:

1. Open your device's app (e.g. Mi Home For Xiaomi) and check the connection status.
2. If the device turns off, check DTIM Interval in the router settings (set 3 instead of the standard one 1-2).
3. Turn it off 802.11r (Fast Roaming) - it may conflict with some IoT gadgets.