The Best Ways to Get Better Cell Signal Inside a Metal Building
6th Jun 2019 /
by Wilson Amplifiers / Comments

The Best Ways to Get Better Cell Signal Inside a Metal Building

metal buildings blog

Metal buildings from steel warehouses to storage facilities to commercial buildings are notoriously bad for getting reliable signal.


While outside 4G & 3G signals are generally reliable, getting signal inside a metal building becomes a chore, because metal is the most disruptive material when it comes to blocking and degrading cell signal.

Wilson Amplifiers provides complete cell phone signal booster installation services for your metal building(s):

Understanding How Cell Phone Signal Works

Cell phone signals are RF (radio frequency) signals nested between AM/FM radio and satellite communications & Wi-Fi in the electromagnetic spectrum.

It starts out strong from the source like a cell tower or cell site. But as it reaches miles in the distance to reach your phone, external obstructions like mountains, valleys, and tall trees and open air path loss weaken signal strength.

Generally outdoors, there is enough signal to make a call in open spaces. But inside a building, cell signal now must also push through walls, interior building material and other interference to make a call, send & receive texts, or use the internet.

That’s why people in the center of a building never get reliable reception with any carrier. They’re always running to the window.

How Cell Phone Signal Strength Should Be Measured

While the number of bars on your cell phone is a decent way of measuring signal strength. It’s actually subjective.

How subjective?

There’s no industry standard. It’s up to the cell phone manufacturers to decide how much is 1, 2, 3, 4 or full bars on their phone. Multiplied by the number of carriers, that’s a lot of confusion. Even the difference between 4G and LTE is not well known.

What may be 1 bar on Verizon might be 2 on AT&T, 3 on Sprint or full bars on T-Mobile despite receiving the exact same signal and performing at the exact same speeds.

But luckily, there's a way to find out your true signal strength. It's called decibel (dB) reading.

Cell phone signal operates with a certain frequency: -50 dBm to -120 dBm.

-50 dBm is full bars. -120 dBm is basically a dead zone. The closer you are to - 50 dBm, the better your signal.

So what does this have to with building material?

Well, building materials basically subtract dB from signal when trying to enter a metal building.

The more it subtracts, the closer you get to -120 dBm, which becomes a dead zone. And metal (see table below) subtracts up to -50 dBm!

Building Material and dB Loss

-32 to -50
Tinted & Low-E Glass
-24 to -40
Concrete & cement (6 inches)
-10 to -20
-8 to -28
-8 to -16
Solid wood
-5 to -12
-4 to -6
Clear Glass
Fiberglass Insulation

Solutions for Getting STRONGER Cell Phone Signal Inside

WiFi is the standard for wireless connectivity. However, having reliable in-building cellular connection is equally important as a secondary system, reducing WiFi congested networks, and providing different sources to connecting to the internet in times of emergency.

IT managers and facility managers are now selecting cell phone signal boosters to improve their indoor cellular connectivity. Whereas building material subtracts dB to signal, cell phone signal boosters add dB to signal by amplifying or bypassing building material.

Let’s look at the top options:

Active DAS (Distributed Antenna System)

DAS stands for distributed antenna system. It’s a system of antennas and remote nodes that improve cellular coverage inside any metal building.

Active DAS uses fiber optic cables and converts analog RF signal to digital for longer cable runs and wider coverage. It also connects directly to the carrier network thus providing the best coverage.

However, it’s expensive, with up to $5 per square foot covered and deployment time is long due to getting carrier permission and necessary requirements. Also, permission is limited to only ONE carrier at a time, so having a multi-carrier active DAS system requires 4 independent requests for permission to connect to AT&T, Verizon, T-Mobile, and Sprint.

[CTA: Need to talk to us about Active DAS solution, contact us]

Passive DAS (Distributed Antenna System)

Passive DAS pulls in off-the-air cellular signal and amplifies it to and from the cell tower. Because it is already using existing carrier signal, it does not require permission and is cheaper and faster to install–about $1 per square foot.

Passive DAS is also known as a cell phone signal booster. It’s commonly popular for home use; however, stronger commercial signal boosters are now entering the small medium enterprise market.

It’s not as powerful as Active DAS and is 110% dependent on the quality of outside signal. Yet it’s a cheaper option for smaller metal buildings.

Best Passive DAS (Commercial Cell Phone Signal Booster) Solutions

Wilson Pro 1100

  • Indoor 4G & 3G coverage up to 35,000 sq ft
  • Works for all phones & all US carriers
  • Stronger & more reliable calls, text, email, and internet data
  • Extended Dynamic Range to ensure continuous connectivity
  • Simple wall-mount installation
  • Up to +70 dB gain, +25 dBm uplink power and +15 dBm downlink power.
  • Expansion kits available for large scale installations
  • 50 or 75 Ohm variants

The WilsonPro 1100 is Wilson Electronics’s latest flagship for small buildings with up to maximum gain of +70 dB, +25 dBm uplink and +15dBm downlink power. XDR (eXtended Dynamic Range) technology makes it ideal for both extremely rural and extremely urban environments.

With that kind of upload power, it has greater reach than any other booster, allowing it to bring in critical signal from far-away cell towers.

Only at
  • FREE shipping.
  • 30 Day money back guarantee.
  • Lifetime technical support exclusive only on Wilson Amplifiers.

Wilson Pro 4300/R

  • Indoor 4G & 3G coverage up to 100,000 sq ft
  • Works for all phones & all US carriers
  • WStronger & more reliable calls, text, email, and internet data
  • Up to 16 inside antennas for wide coverage
  • Up to +70 dB gain, +25 dBm uplink power and +12 dBm downlink power.

Without a doubt, the most powerful cellular signal booster ever made. The secret to the WilsonPro 4300/R is the revolutionary design. Instead of 1 signal booster, the unit houses four (yes, FOUR) independent signal boosters in a rack-mount unit for IT closets or wall-mount unit.

With the need for only one outside antenna and XDR technology, which automatically adjusts for maximum gain no matter how strong or poor the signal, the WilsonPro 4300/R is a clean and easy install unlike other similar signal boosting models.

Only at
  • FREE shipping, no minimum purchase.
  • 30 Day money back guarantee.
  • Lifetime support.

Wilson Amplifiers: The Trusted Name in Boosting Signal

Active or passive DAS, which is the best solution for you? Wilson Amplifiers always has the answer. Depending on the size, scope, and situation, the experts at Wilson Amplifiers can tailor a custom solution for you in time, under budget, and professionally installed.

Services we provide:

  • FREE floor plan analysis with detailed heatmaps & coverage expectations.
  • FREE consultation adhering to your requirements and budgets.
  • Equipment selection from only the best.
  • Site survey from certified wireless technicians.
  • Complete professional active and passive DAS installation & expert project management.

Contact us today to get the best solution for improving your 4G cellular signal indoors.

Get better signal contact our experts 24/7:


Questions or Comments? Contact Us.