Modern wireless networks require not just a signal, but its high-quality distribution. Users who purchase powerful MikroTik equipment often encounter a paradoxical situation: the higher the transmitter power setting, the worse the network performance. This occurs due to an imbalance between the router's radiation output and the sensitivity of client devices, such as smartphones or tablets.
Proper signal level calibration eliminates dead zones, reduces interference, and increases overall channel throughput. In this article, we'll explore the technical nuances of setting this parameter. tx-power, we will consider the impact of the 802.11ac and ax standards, and also learn how to select optimal values for specific operating conditions.
To get started, you need access to the router's management interface. You can use the WinBox graphical utility, the web interface, or the command line via SSH/Telnet. The most accurate results are achieved using WinBox, as it provides full access to all hidden parameters of the wireless card driver.
Transmitter operating principles and signal physics
Radio signal strength is measured in decibels relative to milliwatts (dBm). It's important to understand that the scale is logarithmic, not linear. A 3 dBm increase in power doubles the signal's actual energy, while a 10 dBm increase is a 10-fold increase. However, blindly cranking the slider to its maximum rarely produces the desired result.
The problem lies in the connection asymmetry. The MikroTik router can "shout" very loudly, and the phone will hear it. However, the phone's response signal will be too weak for the router to discern it over the background noise. As a result, you'll see the full signal strength in the interface, but the actual data transfer speed will be low and the ping high.
⚠️ Attention: Exceeding legally established power limits (in Russia, usually limited to 100 mW or 20 dBm for indoor use) may result in fines from the regulator and interference with neighboring networks.
Optimal tuning involves finding a balance where the coverage area matches the physical boundaries of the room, while using the remaining power to penetrate obstacles rather than extend beyond the horizon. It's also important to consider that different antenna models have different gain (dBi), which directly impacts the final coverage.
Configuration interface in WinBox and RouterOS
To get started, run the utility WinBox and connect to your device. Go to the menu Wireless (or Interfaces in newer versions of RouterOS v7). Double-click on your wireless network interface (usually it's labeled as wlan1 or wifi1).
In the window that opens, go to the tab WirelessThe key parameter is located here. tx-powerBy default it can be set to mode default or have a specific numerical value. For fine-tuning, it is recommended to switch the mode to manual (if available in your software version) or simply change the value in the list.
Please note the drop down list tx-power-modeHere you can select a profile, for example, all-rates-fixed, which will lock the power for all connection speeds. This is useful for stabilizing long-range links, but can reduce overall performance in noisy environments.
☑️ Check before changing settings
At the bottom of the window you will see a table Supported RatesIt shows the power that will be applied for different data rates (MCS index). By changing the settings, you can see how the actual output power changes depending on the selected modulation.
Power and usage scenarios correspondence table
The specific value chosen depends on the type of room and the presence of obstacles. Below is a table to help you navigate the ranges for the 2.4 GHz frequency. For 5 GHz, values may differ due to the physical properties of radio wave propagation.
| Power (dBm) | Approximate power (mW) | Use case scenario | Recommendation |
|---|---|---|---|
| 10 - 14 | 10 - 25 | One room, open-space office | Minimal interference, high speed |
| 15 - 18 | 30 - 63 | Apartment with load-bearing walls | Optimal coverage balance |
| 20 - 23 | 100 - 200 | Two-story house, warehouse | It is necessary to break through the ceilings |
| 24 - 27+ | 250 - 500+ | Street links, hangars | For directional antennas only |
Using too much power in a residential building often results in your router jamming your neighbors, who in turn jam you. This causes a "jam" effect in the airwaves, where data packets are lost and need to be retransmitted.
Effect of channel width on power
As the channel width increases (for example, from 20 MHz to 40 or 80 MHz), the noise floor increases. This means that maintaining the same signal quality (SNR) may require a slight increase in power. However, in crowded environments, it is better to use narrow channels (20 MHz) with lower power for stability.
Configuration nuances in RouterOS v7 and new interfaces
With the release of version 7 of the MikroTik operating system, the menu structure has changed. Wireless interface management is now often located in a separate section. wifi (for new chips) or left in the classic wirelessIn new interfaces, the power setting may be located in the section Configuration -> AP -> Channel.
Here the parameter can be called tx-power or adjustable via profile radioThe new drivers feature more aggressive power consumption and temperature management. If the device gets too hot, it can automatically reduce power, ignoring your manual settings.
To access advanced settings in the CLI (command line), use the command:
/interface wireless set wlan1 tx-power=15New versions also feature an automatic power control (ATPC) feature, which automatically adjusts the signal strength based on the connection quality of clients. While this is convenient, manual mode is recommended in challenging conditions. manual often produces a more predictable result.
⚠️ Attention: Interfaces and menu item names may vary depending on the specific device model (hAP, cAP, wAP) and the installed RouterOS version. Always check the documentation for your specific hardware platform.
Diagnostics and signal quality analysis
After making changes, you need to test the results. Don't rely solely on the "sticks" in your phone. Use MikroTik's built-in tools, such as Sniffer or Torch, to analyze the packet flow and the level of retries (retransmissions).
A good way to check is to walk around the premises with a Wi-Fi analysis app running (for example, WiFi Analyzer (on Android). Pay attention not only to the signal strength (RSSI) but also to the signal-to-noise ratio (SNR). A high signal level with a low SNR indicates strong interference.
If you're seeing a large number of CRC errors or retracements, try reducing the power by 1-2 dBm. This often "cleans" the air and increases the actual data rate by removing long-range but weak signal tails that cause interference.
Common mistakes and how to fix them
One of the most common mistakes is frequency band ignorance. At 5 GHz, the signal attenuates faster, so higher power is often required than at 2.4 GHz. However, there's usually less interference here, so chasing the maximum is not worth it.
Another mistake is setting the power without taking the antenna type into account. If you use external antennas with high gain (e.g., 9 dBi), the router's default power may be excessive. In such cases, the effective radiated power (EIRP) should be calculated as the sum of the transmitter power and the antenna gain.
Users also forget about channels. Even with ideal power, if you're on a channel used by ten neighboring routers, you won't have stable performance. Always begin adjusting power after selecting a free or least congested channel.
Optimization for different device types
Different clients react differently to signal strength. Laptops with full-fledged antennas can operate over long distances, while IoT devices (smart bulbs, sensors) have very weak transmitters. By configuring the network for the "weak" device, you guarantee the operation of the entire network.
In enterprise scenarios where multiple access points are used, proper roaming configuration is essential. If the access points' power is too high, the client device will cling to the farthest access point until the last one, instead of switching to the closest one. This reduces the speed of the entire cell.
For guest networks, where coverage is more important than high speed, you can use a profile with a higher power and mandatory use of older, longer-range modulation standards (for example, 802.11n), which will improve coverage in the corners of the building.
How to reset power settings to factory defaults?
To reset all settings to their original values, go to the menu System -> Reset Configuration or use the command /interface wireless default-configuration in the terminal. This will return the default profiles defined by the manufacturer for your region.
Does Country affect available power?
Yes, parameter country In the wireless card settings, you can strictly control the maximum available power and the list of permitted channels according to the laws of the selected country. Changing the country can unlock additional dBm power.
Why did the power drop after reboot?
If your settings aren't saved, you may have changed them in a temporary profile or startup script. Make sure you click the Save button after changing the settings. Apply And OK, and the configuration was saved with the command save or automatically.
Is it possible to exceed power limits programmatically?
In some cases, using non-standard frequencies or operating modes (such as superchannel) allows one to bypass restrictions, but this violates the law and can damage equipment. MikroTik officially does not support exceeding regulatory limits.