FRITZ!Box 6840 LTE Service - Knowledge Base

FRITZ!Box 6840 LTE Service

FRITZ!Box reports "A microwave was detected"

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 allowed by the wireless standard 802.11n. The following message is displayed in the event log of the FRITZ!Box:

  • "Wireless LAN: a microwave was detected; radio channels optimized for 300 Mbit/s temporarily deactivated (2.4 GHz)."

Cause

  • The FRITZ!Box detects sources of interference, for example a microwave in the frequency range around 2.45 GHz. To ensure stable wireless connections, the FRITZ!Box automatically reduces the channel bandwidth from 40 MHz to 20 MHz. 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 the FRITZ!Box.

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

1 Enabling or refreshing the auto channel

The auto channel function allows the FRITZ!Box to check the wireless environment and automatically select the best wireless channel settings. However, since the wireless environment is constantly changing and the FRITZ!Box cannot check again as long as wireless devices are connected to it, you can also refresh the auto channel manually:

  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.

    Note:When the auto channel is enabled and refreshed, all wireless connections to the FRITZ!Box are briefly cleared and then automatically reestablished.

  5. Click the "Refresh Auto Channel" button.

2 Finding the ideal location for the FRITZ!Box

  1. If possible, position the FRITZ!Box in a central location.
  2. Do not position the FRITZ!Box directly in the corner of a room.
  3. Position the FRITZ!Box so that it is as unobstructed as possible, i.e. not directly in back of or under an obstacle such as pieces of furniture or a heater.
  4. Position the FRITZ!Box as high in the room as possible, for example on a shelf.
  5. Position the FRITZ!Box so that there are as few obstacles as possible between it and other wireless devices. Especially metallic objects or objects containing water, for example radiators, refrigerators, or even houseplants, significantly reduce the quality of the wireless signal.
  6. Position the FRITZ!Box so that it is away from other radio transmitters, for example microwaves, wireless speakers, or Bluetooth devices.

3 Establishing a wireless connection to the 5 GHz frequency band

The FRITZ!Box provides a wireless network either in the 2.4 GHz or the 5 GHz frequency band. The 5 GHz frequency band is less affected by interference. 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. Click "Additional Settings".
  5. Select the standard "802.11n+a" from the "Wireless standard" drop-down list.
  6. Click "Apply" to save the settings.
  7. Reestablish the wireless connection to the FRITZ!Box.