FRITZ!Box 7340 – Service - Knowledge Base

FRITZ!Box 7340 – Service

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

The speed of the wireless connection (WiFi) to the FRITZ!Box displayed by wireless devices such as computers, smartphones, or tablets, is significantly lower than the data rate possible with the wireless standard 802.11n. 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)"

Cause

  • The FRITZ!Box recognizes when the wireless channels it uses in the 2.4 GHz frequency band are subject to 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, which is defined by the wireless standard 802.11n. 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:The configuration procedure and notes on functions given in this guide refer to the latest FRITZ!OS for your FRITZ!Box.

Simply proceed as described below. After each measure, check whether the problem persists.

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 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.

2 Establishing a wireless connection to the 5 GHz frequency band

The FRITZ!Box either makes a wireless network available in the 2.4 GHz or the 5 GHz frequency band. The 5 GHz frequency band is not affected by interference as often. Therefore, switch to this frequency band if your wireless devices support the 5 GHz frequency band:

Note:Not all wireless devices support the 5 GHz frequency band.
FRITZ!WLAN Stick AC 430, FRITZ!WLAN Stick AC 860, and FRITZ!WLAN Stick N (v2) support the 5 GHz frequency band.

  1. Click "Wireless" ("WLAN") in the FRITZ!Box user interface.
  2. Click "Radio Channel" in the "Wireless" ("WLAN") menu.
  3. Enable the option "Adjust radio channel settings".
  4. Select the standard "802.11n+a" from the "Wireless standard" drop-down list.
  5. Click "Apply" to save the settings.
  6. Re-establish the wireless connection to the FRITZ!Box.

Wireless connections to the FRITZ!Box are now 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, then this is because of the heavy use by wireless networks in the vicinity.