How to boost your cell phone coverage indoors

We all know the story: you cell phone rings, Caller ID shows its the call you have been waiting for, you answer the phone says Hello. Then silence. The phone shows you are connected but you can hear nothing. Instantly you leap to your feet and start marching around the room shouting into the phone hoping that you get something through and find a spot where the signal is strong enough.

Paolo Marangon, General Manager: Mobility Duxbury Networking a Specialist Networking Distributor confirms that “around 80% of the calls we make are made from inside a building and this is where there is the greatest levels of interference from building materials and other electronics”

This is a real problem and there has to be a solution.

I have written about a little miracle in a box before, called Cel-Fi which is in essence a complicated technology that boosts the cell phone signal. It is made up of two parts. The first is a “windows unit” that you plug into the wall socket and it picks up your specific cell phone provider’s networks. The Indoor Coverage Unit you plug into a wall socket at another point in the house/ office/ warehouse/ factory. The two units “find” each other and your phone’s signal dramatically increases.

Cel-Fil setup

In order to properly test this system, I had to find a place where at best there is 1 bar of signal. A place where making is phone call is always a challenge and unit the internet on your phone is simply not an option.

I found such a place outside of Vereeniging – a town outside of Johannesburg. This is where I spent my weekend testing the equipment.

The Test and the Result

I wasn’t aiming high. All I wanted to achieve was boost my signal from no bars to 3 bars. If I could do that, it means I could comfortably make a phone call and even use the internet.

I planned on needing the entire weekend to fine tune the equipment and finding just the right spot. This was not necessary as within 5 minutes I was operational. No technical experience needed as this was literally plug-and-play.

I plugged the Windows Unit in and it’s indicator showed the famous 1 bar. According to the manual, that is all you need. Semi-hopeful, I placed the other unit in another room and switched it on. The indicator on that unit showed that it found the Windows unit and there is a strength of 7. So far so good.

Cel-Fi Windo UnitCel-Fi Indoor Coverage Unit

The real test is in the phone. So I whip out the phone and I look at the signal strength and I was shocked. A full 5 bars !

I made some calls and sent out some Tweets – no problem.

Being a typical techie, I thought that this could be a coincidence. Maybe the cell network have fixed this places black hole and now they is signal without the Cel-Fi.

So I switched it off and looked at my phone. Immediately the signal strength showed 0 bars. I switched it back on and instantly 5 bars.

I repeated this test throughout the weekend and it never failed. Off = no signal, On = full signal. Simple as that.

image – Cel-Fi ON = 5 Bars at 14:40

image– Cel-Fi OFF = 0 Bars at 14:41

image– Cel-Fi ON = 5 Bars at 14:41

Amazing !

So where can you get one ?

As in the original post – you can not walking to a retailer and buy one. You have to go through your cellular provider as according to ICASA only the networks can supply and sell this kind of equipment.

So if you want one, follow the steps I outlined originally. Be persistent, sent emails, make phone calls, Tweet about it and eventually you will get one.


  1. i also have the same problem in my room. I can’t make calls , connect to the internet etc

    so who can i contract to get this device i really need it

  2. I had to buy a network extended in my house but it was stolen one night light that. It’s really terrible indoors. Once I step into may apartment, the network disappears.

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