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Knowledge document #3337
FRITZ!Box 6850 LTE
This support document is available for the following products:

Throughput of the mobile connection is too low

The throughput displayed in the FRITZ!Box user interface for the mobile connection is significantly lower than the speed guaranteed by the mobile network provider.


  • 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 places, you will not be able to fully achieve the guaranteed throughput. This is why mobile network provider say that they offer speeds of "up to" a certain value.

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

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

1 Installing the latest FRITZ!OS for the FRITZ!Box

Installing the latest FRITZ!OS makes your FRITZ!Box compatible with the latest mobile network technology used by mobile network providers in their radio cells:

  1. Install the latest FRITZ!OS on the FRITZ!Box.

2 Selecting the frequency band

If several frequency bands are available at your location, you may be able to increase the throughput of the mobile connection by selecting a specific 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 mobile network providers support all frequency bands.

  1. Click "Internet" in the FRITZ!Box user interface.
  2. Click "Account Information" in the "Internet" menu.
  3. In the section "LTE Frequency Band", enable the option "Manual" and disable all frequency bands except "2.6 GHz / band 7 (FDD)".
  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 "1.8 GHz / band 3 (FDD)" and "800 MHz / band 20 (FDD)", and use the frequency band the FRITZ!Box can achieve the highest throughput with.

3 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 network 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 current signal strength of the antennas is displayed by the LEDs on the FRITZ!Box (in five levels) and in the user interface.
  5. Select a location for the FRITZ!Box where the signal strength 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. Place the FRITZ!Box as close to an outside wall as possible. If you know where your provider's radio cell is located, place 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 such as pieces of furniture or a heater.

4 Connecting an outdoor antenna

If you are using the FRITZ!Box in the fringe area of the network coverage of your mobile network provider (outdoor coverage area) or in a building that exhibits a strong shielding effect, the two mobile network antennas included in the package may not be sufficient for optimal radio traffic. In this case, you can increase the transmission and reception power of the FRITZ!Box by using an outdoor antenna (for example on your balcony or mounted on your roof):

5 Contacting your provider

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

  1. Have your mobile network provider check your mobile connection.