FRITZ!Box 7369 Service - Knowledge Base

FRITZ!Box 7369 Service

FRITZ!Box reports "Wireless LAN transmission quality increased by reduced channel bandwidth"

Computers, smartphones, or other wireless devices display a low speed for the wireless connection (WiFi) to the FRITZ!Box's 2.4 GHz frequency band displayed. The following message is displayed in the event log of the FRITZ!Box:

  • "Wireless LAN transmission quality increased by reduced channel bandwidth (2.4 GHz)"


  • The FRITZ!Box recognizes when the wireless channels it uses in the 2.4 GHz frequency band are in heavy use by other wireless networks. To ensure stable wireless connections, it automatically reduces the channel bandwidth from 40 MHz to 20 MHz. This FRITZ!Box behavior is conform to wireless coexistence.

Although wireless devices then display a lower data rate, the user data rate is increased because there is less interference and the wireless connection is no longer affected by constant retransmissions.

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

1 Selecting the best wireless channel

In the factory settings, the FRITZ!Box automatically checks the wireless environment and selects the wireless channel settings. However, with some disturbances it cannot determine the best wireless channel for all wireless devices. Therefore, select the wireless channel in the FRITZ!Box that is least affected by interference in the wireless environment:

  1. Click "Wireless" ("WLAN") in the FRITZ!Box user interface.
  2. Click "Radio Channel" in the "Wireless" ("WLAN") menu.
  3. Click the link "Show disturbances to wireless network" in the "Wireless Environment" section.
  4. Use the diagram to determine which channel in the lower frequency range is least affected by other wireless networks and interference.
  5. Enable the option "Adjust radio channel settings" in the "Radio Channel Settings" section.
  6. From the drop-down list "Radio channel", select the wireless channel that was the least affected.
  7. Click "Apply" to save the settings.
  8. If the issue with your wireless connection still occurs, repeat steps 3 - 7 with a wireless channel in the middle and then with one in the higher frequency range. Once you have finished testing, use the wireless channel that was least affected by disturbances.

    Important:The diagram of the wireless environment only reflects the current situation! The allocation of the frequency band can change significantly over the course of the day because many wireless networks are turned on when in use. Therefore, check several times to see which wireless channels are least affected by interference.

Now wireless connections to the FRITZ!Box are established with the maximum possible data rate.

Note:If the message "Wireless LAN transmission quality increased by reduced channel bandwidth [...]" is still displayed in the event log of the FRITZ!Box, this is due to the heavy use by wireless networks in the vicinity.