How many internal antennas for a signal repeater?

How many internal antennas for a signal repeater?

How many antennas does a cellular signal repeater need to cover the entire office, home. warehouse, garage? What power does a GSM repeater need to have to drive a certain number of indoor antennas, and what items should be added to the basic kit (connectors, splitters, couplers, cables)? 

We first consider the square footage and number of levels dellof the indoor environment where the cellular signal is to be improved. As a general guideline, every 250/300sqm and per floor an additional indoor antenna would need to be added.

Next comes the choice of signal repeater, which has a power rating expressed in dBm (10 dBm the smallest and 23 dBm the largest), and this value, when interpreted as in the summary below, tells us how many indoor antennas can be added to that repeater model.

The smaller GSM and/or 3G and/or 4G repeaters, i.e., 10 dBm, are designed for only one indoor antenna, i.e., a maximum of 300sqm and one level. These signal repeaters cannot be extended in the future by adding more indoor antennas.

Starting with models with13 dBm power, we can add indoor antennas. To simplify, we have already put together extension sets. See below:


  1. What is an extension set for a signal repeater?
    1. A complete set
    2. A simple installation
  2. Choose the right extension for the indoor environment
    1. Number of indoor antennas needed
    2. Select the type of indoor antennas
    3. The length of the cable can be customized for each antenna
  3. Other things to consider
    1. Contact us for personalized advice


1.What is an extension set for a signal repeater?

Here we show you an alternative for your whip antenna, if you want to have a different antenna from this one or if you want to add more antennas for your project. The "Customize Your Kit" tab is designed to make it easier for you to choose. This way you will not forget anything and you will have a list of all the products added to your kit.

Take, for example, one of the smaller signal repeaters, the RF EL10-L model, with a power of 10 dBm: as just seen, this reduced power does not allow us to add additional indoor antennas. We can still customize the kit, however, by replacing the basic supplied stylus antenna with a set 1 indoor panel or ceiling antenna (including 10m coaxial cable).


1.1A complete set

With a more powerful repeater, i.e., 13 dBm, for example, the RF-EL13-H model, we can order an "extension set 2 indoor antennas," which already contains everything and allows us to choose between ceiling or panell antennas.

The cables for the two antennas are 10 meters, but can also be ordered in longer lengths. All these accessories, of course, are compatible with GSM 3G and 4G cellular networks.


1.2A simple installation

The contents of the extension set is to be connected to the output of the cellular signal repeater, instead of the indoor antenna.

1. Connect the N male-N male connector to the INDOOR jack on your repeater

2. Attach the splitter or coupler to the connector

3. Connect the coaxial cable to the splitter

4. Connect the indoor antenna to the coaxial cable

In this way you have quickly connected an extension set to the signal repeater. Do not forget that you have also connected the outdoor antenna before turning on the device


2.Choose the right extension for the indoor environment

Depending on the configuration of your premises, including the number of floors of your residential or commercial premises, simply define in advance the number of indoor antennas needed for good coverage. Useful to keep in mind that the waves of an antenna will not be able to pass through thick walls, concrete, stone walls and a floor, but up to two plasterboard walls.

Then select the type of each antenna according to the room where it will be installed: panel or ceiling. Ceiling antennas have a 360-degree spread below it, while panel antennas have a 180-degree spread to the side and forward. Next, estimate the length of the cable feeding each antenna.


2.1Number of indoor antennas needed

Establishing the number of indoor antennas needed to cover your indoor environment is quite simple, summarized in the table below. For projects involving more than 4 indoor antennas we invite you to contact our team, we will gladly give you our opinion.


2.2Select the type of indoor antennas

Do your premises have suspended ceilings? If so, use ceiling antennas. They are installed in the center of the room to be covered and are the easiest and fastest installation solution. The result is perfect because the antenna radiates 360°. The ceiling antenna is very effective, more discreet. Without a false ceiling or for rooms with very high ceilings, however, the panel antenna is better. With the included mounting plate, installation is easy; the cable can be laid "above ground" and routed, for example, along ceiling battens or through a conduit.


2.3The length of the cable can be customized for each antenna

The standard length is 10 meters, but longer cables can be ordered.

Useful to keep in mind that the longer the cable, the higher the signal loss. Cables that are too long will take a few too many dB off the power of your signal repeater.


3.Summary table


Signal repeater power




1 indoor antenna

10 dBm repeater

2 indoor antennas

13 dBm repeater

3 indoor antennas

15 dBm repeater

4-6 indoor antennas

20 dBm repeater

6-10 indoor antennas

23 dBm repeater



3.1Contact us for personalized advice

Not sure which repeater is right for you? Take a look here! How to choose the right mobile signal booster?.

In any case, if you have any doubts, or if you prefer that we do the math for you, no problem, send an e-mail message to Our team will offer you the most suitable solution to finally solve your problem of poor cellular reception. If you have a chance to send the floor plan of the indoor environment, even better!