FRITZ!Box 7369 Service - Knowledge Base

FRITZ!Box 7369 Service

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

Wireless connections (WiFi) according to wireless standard 802.11n are established with a throughput that is considerably less than 300 Mbit/s. The following error 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 that the wireless channels it uses in the 2.4 GHz frequency band are subject to heavy use by other wireless networks. In order to still guarantee stable wireless connections, the FRITZ!Box automatically reduces the channel bandwidth to 20 MHz. Although the wireless devices display a lower throughput as a result, the user throughput is higher because it is not affected by retransmissions. This FRITZ!Box function ("wireless coexistence") complies with wireless standard IEEE 802.11n.

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 of the wireless device. Therefore, select the wireless channel in the FRITZ!Box that is least affected by disturbances 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 on the link "Show disturbances to wireless network" in the "Wireless Environment" section.
  4. Use the graph to determine which channel in the lower frequency range is least affected by other wireless networks and sources of interference.
  5. Enable the option "Adjust radio channel settings" in the "Radio Channel Settings" section.
  6. Select the wireless channel that was affected the least from the drop-down list "Radio channel".
  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 bands 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.

The FRITZ!Box now establishes wireless connections with the highest possible throughput.

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