FRITZ!Box 6820 LTE – Service - Knowledge Base

FRITZ!Box 6820 LTE – Service

Throughput of the mobile connection is too low

The FRITZ!Box displays the speed of the mobile connection on the user interface under "Internet > LTE Information > Mobile Communications" in the "Throughput" line. According to this, the throughput is significantly lower than the speed specified in your mobile contract with your mobile network operator.


  • The throughput of the mobile connection depends on factors such as the distance from the mobile station, the shielding effect of the walls of your own house, of neighboring houses, and also trees. Storms and other users located in the same radio cell can also reduce the throughput.

    Important:In many cases, you will not be able to fully achieve the throughput stipulated in your mobile contract. Therefore, mobile network operator say that they offer speeds of "up to" a certain value.

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 Using a different modem version

The software version for the FRITZ!Box's integrated mobile broadband modem undergoes constant development with each FRITZ!OS to ensure that it can establish optimal mobile connections under all circumstances. However, in rare cases the FRITZ!Box may be able to negotiate higher data rates with certain versions. Therefore, test the current and the previous modem version:

Using the latest FRITZ!OS

The modem version is part of FRITZ!OS. Make sure that the FRITZ!Box is using the latest FRITZ!OS and therefore the latest modem version:

Using the previous modem version

If the problem occurs with the latest modem version (for example after updating FRITZ!OS), test the modem version of the previous FRITZ!OS:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "LTE Information" in the "Internet" menu.
  3. Click on the "Reception" tab.
  4. Enable the option "Use previous software version for the integrated mobile communications modem".
  5. Click "Apply setting" to save the settings.

Now the FRITZ!Box enables the previous modem version and reinitializes the modem. Afterwards, the FRITZ!Box attempts to establish a mobile connection again.

2 Selecting the type of mobile communication

Depending on your mobile network operator and contract, if there are several radio cells at your location, you may need to manually select the desired type of mobile communication in the FRITZ!Box:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "Account Information" in the "Internet" menu.
  3. Select "LTE only" from the drop-down list "Type of mobile communication".
  4. Click "Apply" to save the settings.
  5. If you are now no longer able to connect to the mobile network, test the setting "UMTS only" and then "GSM only".
  6. Use the type of mobile communication with which the FRITZ!Box achieves the highest throughput.

3 Selecting the LTE frequency band

If several LTE frequency bands are available at your location, you may be able to increase the throughput of the mobile connection by selecting a particular frequency band:

Note:In Germany, the frequency bands 2.6 GHz, 1.8 GHz, and 800 MHz are used. Not all frequency bands are available at all locations, and not all LTE providers support all frequency bands.

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "Account Information" in the "Internet" menu.
  3. Select "Only 2.6 GHz / band 7" from the drop-down list "LTE frequency band".
  4. Click "Apply" to save the settings.
  5. If the FRITZ!Box can establish a mobile connection using the frequency band you selected:
    1. Click "Internet" and then "LTE Information".
    2. Click on the "Mobile" tab.
    3. Check which speed is displayed in the "Throughput" line.
  6. Repeat steps 2 - 5 with the frequency bands "Only 1.8 GHz / band 3" and "Only 800 MHz / band 20", and use the frequency band the FRITZ!Box can achieve the highest throughput with.

4 Finding the ideal location for the FRITZ!Box

You can use the alignment aid to find the ideal location for the FRITZ!Box and the best position for the mobile broadband antennas:

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "LTE Information" in the "Internet" menu.
  3. Click on the "Reception" tab.
  4. Click the "Start Alignment Aid" button.
    • Now the FRITZ!Box shows the signal strength of both antennas.

      Note:When the alignment aid is active, the current signal strength is also displayed in a five-level display on the FRITZ!Box LEDs. This means that you can also find the best location for the FRITZ!Box without using the FRITZ!Box user interface.

  5. Select a location for the FRITZ!Box where the value shown is as high as possible. When doing so, note the following:
    1. Do not set up the FRITZ!Box in the corner of a room.
    2. Position the FRITZ!Box as close to an outside wall as possible. If you know where your provider's radio cell is located, position the FRITZ!Box by the wall facing the radio cell.
    3. Position the FRITZ!Box so that it is as unobstructed as possible, i.e. not directly in back of or under an obstacle (for example pieces of furniture, heater).

5 Contacting your provider

Your mobile network operator may have throttled the mobile connection if a particular data limit was exceeded, or your operator may be experiencing technical difficulties:

  • Have your mobile network operator check your mobile connection.