The outdoor antenna for mobile signal: which one, where, and pointing where

An antenna on its own gives your phone nothing

This is the most expensive misunderstanding in the trade, and it is worth clearing up first. An outdoor antenna collects signal, but your phone has nowhere to plug it in. For it to be of any use, what it collects has to be put back into the air inside the house, and that is the booster's job — the part that transmits and the part that needs the operator's authorisation. An antenna with no booster is a pole on the roof.

The other thing called a '4G antenna' is the one that screws onto a router with a SIM card. That is a different product, it is home internet, and it is not what we do: we install no routers and we create no WiFi networks.

Where the antenna goes depending on your type of home

The job is not the same in a villa as on a fourth floor. What changes is where the signal is picked up, how many antennas are needed indoors and — this surprises a lot of people — how many people you have to ask for permission.

In a villa on an urbanisation. The roof is yours, so you decide where the antenna goes and which way it points: that is half the job, and it is the easiest case. What usually complicates it is something else. Urbanisations are built in one go and on the edge of town, every house is the same height — none blocks another, but none rises above the rest either — and between the ground floor and the first there is a reinforced concrete slab, which is what cuts the signal between floors. That is why the indoor antenna usually ends up in the stairwell or the hall: from there it covers both. It is worth checking the urbanisation's rules first, because some of them say what may be visible from the street.

In a flat. Here you need two permissions, not one. There is no roof of your own: the place to pick up the signal is the façade, your own terrace or the communal roof — and the communal roof is a communal element. On top of the operator's authorisation you have to go through the owners' association, and the cable cannot run wherever it likes. We say so before charging for the survey, because it is the step that most often delays an installation in a block. In exchange, the signal outside is usually good here: the enemy is not distance, it is the concrete in the walls and, in recent builds, the metal-coated glass in the windows, which reflects signal the same way it reflects heat. In an inner flat or on a ground floor the effect is twice as noticeable.

In a town house between party walls. It is long, narrow and joined to its neighbours on both sides, so signal can only come in through the street façade and the yard at the back. The front room usually works; the kitchen and the back bedrooms do not. Old load-bearing walls, solid brick or rubble masonry, eat considerably more signal than a modern partition, and a narrow street blocks the line of sight at ground level even when the view from the roof is perfect. Here it is normal to need more than one indoor antenna, because a single one does not reach from the façade to the yard.

In an isolated country house. It is where we say no most often. Outside the built-up area the nearest mast can be several kilometres away, and the only usable thing is often the 800 MHz band, which travels far but arrives worn out. The pole sometimes has to rise above the roof to clear a terrace bank or a line of trees, earthing and lightning protection stop being a detail, and the power supply is not always steady: it is the one situation where we genuinely recommend the backup battery. And it is also where the survey most often ends in there being nothing to boost: if there is no signal on the roof, we do not manufacture it.

This describes the four cases we run into most around here, not a rule: some houses are all four at once. Each town page says which ones predominate in that municipality.