FRITZ!Box 7490 Service - Knowledge Base

FRITZ!Box 7490 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 450 Mbit/s. One of the following error messages is displayed in the event log of the FRITZ!Box:

  • "Wireless LAN transmission quality increased by reduced channel bandwidth (2.4 GHz)"
  • "Wireless LAN transmission quality increased by reduced channel bandwidth (5 GHz)"

Cause

  • 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.

Important:Some of the settings described here are only displayed if the advanced view is enabled in the user interface. The configuration procedure and notes on functions given in this guide refer to the latest FRITZ!OS

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

1 Enabling or refreshing the auto channel

If the auto channel is enabled, the FRITZ!Box checks the wireless LAN location and automatically selects the optimum wireless channel settings. However, the allocation of the frequency bands can change significantly over the course of the day. The FRITZ!Box does not refresh the auto channel as long as wireless devices are still connected with it. You can therefore manually refresh the auto channel at any time:

Note:All wireless connections to the FRITZ!Box are cleared and then automatically re-established when you enable or refresh the auto channel.

  1. Click "Wireless" ("WLAN") in the FRITZ!Box user interface.
  2. Click "Radio Channel" in the "Wireless" ("WLAN") menu.
  3. Enable the option "Set radio channel settings automatically (recommended)".
  4. Click "Apply" to save the settings.
  5. Click the "Refresh Autochannel" button.

2 Establishing a wireless connection to the 5 GHz frequency band

The FRITZ!Box provides a wireless network in the 2.4 GHz as well as the 5 GHz frequency band. The 5 GHz frequency band is subject to interference less frequently. 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 Network" in the "Wireless" ("WLAN") menu.
  3. Enable the option "Wireless radio network enabled" in the "5-GHz Frequency Band" section.
  4. Enter a different name in the field "Name of the wireless radio network (SSID)" so that you can distinguish the 5 GHz wireless network from the 2.4 GHz wireless network in the future.

    Important:Not all wireless devices support all special characters. Therefore, only use standard Latin letters (not letters such as ä, ë, ö, ü, á, é, í) and numbers in the wireless network name.

  5. Click "Apply" to save the settings.
  6. Establish a wireless connection to the FRITZ!Box wireless network with the name (SSID) that you assigned to the 5 GHz frequency band.

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.