How does a GSM Repeater work?

How does a GSM Repeater work?

As the name 'repeater' indicates, a GSM repeater, also known as a GSM amplifier, repeats the mobile signal. An outdoor antenna picks up the signal, the repeater amplifies this signal and the indoor antenna transmits the signal inside. In this article, you can read how a GSM repeater works and what you should pay attention to during installation.



1. How does a GSM repeater work?

Each standard GSM repeater set is supplied including an outdoor antenna, an indoor antenna, and 10 meters of coaxial cable. The outdoor antenna is mounted in a place where the signal is (reasonably) good, for example on the roof, the facade, or a chimney. Via a coaxial cable, the signal is brought to the GSM repeater, which amplifies the signal. The indoor antenna then broadcasts the signal inside. So you bring in the GSM signal from outside.


See image below:

Installatie GSM repeater

Image 1 - With the help of a GSM repeater you can retrieve the mobile signal.


2. What are the different accessories?

  • An outdoor antenna nummer 1picks up the mobile signal from the transmission tower. There are several models. Which one you need depends, among other things, on the distance to the transmission tower and the quality of the outside signal.
  • The signal is brought to the GSM repeater with a coaxial cable number 2 , which amplifies the signal.
  • With a simple setup, the indoor antenna number 3  is screwed directly onto the repeater and transmits the signal inside. There are also different models of indoor antennas. It is also possible to move the indoor antenna using coaxial cable.


3. Is it possible to amplify the signal in multiple spaces?

Of course! If the building to be reinforced involves several floors or rooms, you can connect several indoor antennas to one GSM repeater (see picture 2). The more powerful a repeater is, the more indoor antennas can be connected. In this way, you create a bigger reach.


Installatie 2 binnenantennesImage 2 - This way you can mount multiple indoor antennas


  • An overview of the maximum number of indoor antennas to be mounted:
    10dBm repeater (300 m2) - max. 1 indoor antenna
    13dBm repeater (700 m2) - max. 2 indoor antennas
    15dBm repeater (1,000 m2) - max. 3 indoor antennas
    20dBm repeater (2,000 m2) - max. 6/8 indoor antennas

The image above shows the outdoor antenna number 1 and the GSM repeater number 2. Instead of one indoor antenna (see picture 1) number 3, picture 2 shows an extension set for two indoor antennas number 4. The mobile signal is always brought from the outdoor antenna to the GSM repeater with a coaxial cable. You can mount several indoor antennas using a splitter. You can also do this using coaxial cables. In the example above, the GSM repeater works for two separate rooms. Expansion kits are available for two, three, or four indoor antennas. Everything is included: the splitter, coax cables, and the indoor antennas.

The extension sets are available with different indoor antennas and different lengths of coaxial cable.
Whether it is a 500 m² barn with concrete walls, an underground parking lot of 4,000 m², or offices spread over several floors, GSM REPEATER SHOP offers a solution that fits your situation. Please feel free to contact us for specific and non-binding advice.


4. Which GSM repeater do I need?