How to choose a cell signal booster for a truck or building

A booster amplifies the signal you already have.

A cell signal booster has three parts. An outside antenna picks up the signal from the tower. An amplifier boosts it. An inside antenna rebroadcasts it to the phones nearby, and the same path carries their signal back out to the tower.

It can only work with what reaches the outside antenna. If a phone held outside the building or truck gets a usable signal, a booster can bring that signal inside. If there's no signal outside, there's nothing to amplify.

Boosters help most where the signal is fine in the parking lot and gone at the desk. Metal buildings, concrete and coated low-E glass all keep signal out. A truck cab works the same way. The metal body blocks some of the signal, and a roof antenna gets above it.

Check the outside signal before you buy.

Walk the outside of the building with a phone on each carrier your staff use, and note where the signal is strongest. The roof is usually better than ground level. Many phones can show signal strength as a number in dBm, which tells you more than bars.

Building kits are sold by the square footage they cover, and that figure assumes a strong outside signal. With a weak one, coverage can shrink to the rooms nearest the inside antenna. HiBoost, for example, rates its 15K Smart Link kit at 7,000 to 15,000 square feet depending on the signal outside.

The outside and inside antennas need distance between them. Mounted too close, the booster picks up its own output, then cuts its gain or shuts down to protect the network. Building kits want the outside antenna on the roof or high on an outside wall, with the inside antenna well below and away from it.

Vehicle and building kits are not interchangeable.

Building boosters are certified for fixed, in-building use. Vehicle boosters are certified for use in a vehicle, and FCC rules allow them less gain than building boosters. Use each one where its label says.

A vehicle kit puts an antenna on the roof and a small antenna inside the cab. It works best for phones near that inside antenna, so plan on a phone mount close to it rather than a phone in a bag behind the seat.

For a fleet, choose between magnet-mount and permanent antennas. A magnet mount needs no drilling and can move to another truck. A permanent NMO mount goes through the roof and stays with the vehicle. Over-the-road trucks have kits of their own, such as the OTR version of weBoost's Drive Reach for semi trucks.

Vehicle and building kits are at /shop/signal-boosters.

Register it with the carrier.

FCC rules require you to register a consumer signal booster with your wireless carrier before you use it. The major carriers have agreed to allow boosters that meet the FCC's technical rules, and registration is usually a short online form. Register with every carrier your staff use.

A consumer booster must also be used with the antennas and cables it was certified with, and turned off if the FCC or a carrier asks. Those terms are printed on the label and in the manual.

Larger or multi-floor buildings may need an industrial booster or a distributed antenna system (DAS). Both need the carrier's permission and a design, so they're quoted as projects.

Know what a booster can't do.

A booster can't create a signal where there isn't one outside. It also can't fix a busy tower. If the tower is congested, a stronger signal still gets slow data.

It doesn't amplify every 5G band. A consumer booster covers the bands on its spec sheet, usually the low- and mid-band frequencies carriers use for LTE and some 5G. Most don't cover the C-band and 2.5 GHz frequencies that carry much of the fastest 5G, so a phone can show more bars on a slower band. Check the band list against what your carrier uses in your area.

It does nothing for Wi-Fi, and nothing for a device out of range of the inside antenna.

When a cellular router is the better answer.

A booster helps phones. It doesn't give your network a backup internet line. To keep card terminals, cameras, VoIP phones and office computers online when the wired internet goes down, you need a cellular router with its own SIM and data plan.

The router connects to your gateway as a second internet connection. When the main line drops, the gateway fails over to cellular, then switches back when the line returns. Dual-SIM routers can also switch between two carriers. Where the signal inside is weak, choose a router with external antenna connectors and mount the antennas outside.

Trucks follow the same logic. A booster helps the driver's phone. A vehicle router gives tablets, laptops and other devices in the truck a connection of their own.

Routers for backup internet and vehicles are at /shop/cellular-routers, and gateways that handle failover are at /shop/routers-gateways.

Before you order.

For a building, a fleet or both, send these details through /rfq?department=network-hardware.

• Outside signal readings for each carrier your staff use
• Square footage and building material, or vehicle type and roof
• Where the outside antenna can mount, and the cable route inside
• Which carriers the booster needs to be registered with
• Whether you need better calls on phones, backup internet for the network, or both