Here's the honest version. Most buildings that need better indoor cell signal don't need a million-dollar antenna system. They need something much simpler.
A DAS (Distributed Antenna System) takes cellular signal and spreads it throughout a building using a network of antennas. It's the reason your phone works inside stadiums, hospitals, and airports. There are three types, and they range from "we can have this running by Friday" to "we'll need 18 months and a seven-figure budget."
The difference between them comes down to what carries the signal through the building (coaxial cable, ethernet cable, or fiber optic), whether the remote units need power, and how much of the system you need to build from scratch. That decision depends almost entirely on how big your building is and how many people need to use it at once.
Over 80% of cellular data sessions happen inside buildings, which means this isn't an edge case. It's the normal situation. If you're dealing with dead zones, dropped calls, or slow data indoors, one of these three approaches will fix it. The question is which one.
The Quick Comparison
|
Passive DAS |
Hybrid DAS |
Active DAS |
|
|---|---|---|---|
|
How it works |
Signal booster + coax cable + antennas |
Ethernet or fiber backbone + powered remote units + coax to antennas |
Fiber optic network + powered radio units everywhere |
|
Cost per sq ft |
$0.50 to $1.00 |
$1.00 to $2.00 |
$2.00 to $10.00 (depends on carriers) |
|
Building size sweet spot |
Under 100,000 sq ft |
100,000 to 500,000 sq ft |
Over 500,000 sq ft |
|
Install timeline |
Days to 2 weeks |
A few weeks |
6 to 18 months |
|
Carrier approval needed |
No |
No (most setups) |
Yes, from each carrier separately |
|
Works with all carriers |
Yes, automatically |
Yes |
Only the carriers that participate |
|
Adds network capacity |
No (coverage only) |
Some |
Yes |
The cost difference alone tells most of the story. For a 200,000 sq ft building, passive DAS runs $60,000 to $200,000. Active DAS for that same building runs $400,000 to $2,000,000 depending on how many carriers participate. Same building, same signal problem, wildly different price tags.
Passive DAS
The One Most Buildings Actually Need
Passive DAS is the simplest of the three and the one that fits the widest range of buildings. It works the same way a home signal booster works, just on a larger scale with more antennas spread across a bigger area.
An outside antenna on the roof captures cell signal from nearby towers. A commercial amplifier boosts it. Coaxial cable carries that boosted signal through the building, with splitters dividing it to feed multiple indoor antennas mounted in ceilings, hallways, and common areas. No fiber, no powered equipment at each antenna, no carrier involvement.
Here's a stat that puts things in perspective. 88% of commercial buildings in the US are 25,000 square feet or smaller. For those buildings, a single commercial signal booster with a handful of well-placed antennas solves the problem completely. Even buildings up to 100,000 square feet can be covered with a single commercial amplifier. For larger buildings, you add more amplifiers. A children's hospital in Southern California covers over 450,000 square feet using 34 amplifiers and 370 antennas, all passive DAS. It saved 80% compared to the active DAS quotes they received.
What makes passive DAS appealing
The practical advantages go beyond cost. Installation takes days, not months. There's no carrier coordination required because signal boosters are FCC pre-approved to work with all carriers simultaneously. You don't need to call T-Mobile, Verizon, and AT&T and wait for each one to sign off. The system amplifies whatever signal exists outside and broadcasts it inside, all carriers at once.
If your building situation changes (you move, expand, or reconfigure), the equipment can be repositioned. Try doing that with an active DAS that has fiber running through every wall.
The equipment itself is low-maintenance. There are no monthly fees, no subscriptions, and the hardware typically lasts 7 to 10 years. Most systems include cloud-based monitoring so you (or we) can check on performance remotely without sending someone to the building.
Whether you own the building or lease your space matters, though. Tenants typically need landlord approval for the roof antenna, so that's a conversation to have early. Some landlords handle cell signal as a building amenity, especially in newer Class A offices where they know the Low-E glass is killing coverage for every tenant.
Where passive DAS hits its limits
The constraint is coaxial cable. Every foot of cable between the amplifier and the antenna costs you signal. At cellular frequencies, a good quality cable loses about 3 to 7 dB per 100 feet (with higher frequency bands losing more). Run 300 feet of cable and you've lost a significant chunk of the signal the amplifier worked so hard to boost.
This is why passive DAS works best when cable runs stay under about 300 feet. In buildings much larger than 100,000 square feet (with a single amplifier), the cable runs get too long and the signal at the far antennas gets too weak. You can solve this by adding more amplifiers in different zones, which is how that 450,000 square foot hospital made it work. At some point, though, it makes more sense to use fiber for the long runs, which is where hybrid DAS comes in.
The other limitation is capacity. Passive DAS improves signal strength (coverage), but it doesn't add capacity to the network. For most buildings, that's totally fine. An office with 200 people doesn't need extra capacity, it just needs the signal to reach everyone's phone. Capacity only becomes an issue when dealing with thousands of simultaneous users in one place, like a stadium or convention center.
Active DAS
The Heavy Hitter for Massive Venues
Active DAS is a completely different animal. Instead of coaxial cable carrying the signal, it uses fiber optic cable and powered radio units throughout the building.
The system starts with a headend (a central unit, usually in an equipment room) that converts the cell signal into light and sends it across fiber optic cable. At the other end, powered remote radio units convert the light back into cell signal and feed it to nearby antennas. Because fiber doesn't lose signal the way coax does, active DAS can cover enormous buildings, think stadiums, airports, convention centers, and sprawling hospital campuses.
AT&T Stadium in Arlington, Texas has over 2,300 remote radio units. The Las Vegas Convention Center spent $18 million on its Corning active DAS system. These are massive installations that take a year or more to design and build.
When active DAS is the right call
Active DAS earns its price tag in situations where nothing else will work.
Venues with tens of thousands of people using their phones at once (stadiums, arenas, major convention centers) need the capacity management that only active DAS provides. The system can add real network capacity, not just amplify existing signal, which means it can handle the spike when 70,000 fans are streaming video and posting to social media at halftime.
Buildings over 500,000 square feet with complex layouts (multi-tower hospital campuses, major airports) need the distance advantage of fiber. Coax simply can't carry signal far enough without losing too much.
Multi-carrier environments where each wireless carrier needs their own dedicated connection also require active DAS. This means coordinating with each carrier individually, which adds months (sometimes years) to the timeline and significant cost to the project.
Why most buildings don't need it
For the vast majority of commercial buildings, active DAS is overkill. The cost is 5 to 10 times higher than passive DAS. Installation takes 6 to 18 months instead of days. You need carrier approval from every carrier you want to support, and getting on a carrier's deployment queue can take a year or more by itself. You need a dedicated equipment room with power and cooling. You need professional RF engineering.
If your building is under 500,000 square feet and you don't have a stadium-level crowd problem, there's almost certainly a simpler and cheaper way to solve your signal issues.
Hybrid DAS
The Middle Ground
Hybrid DAS borrows from both approaches, though "hybrid" can mean different things depending on the system. The general idea is the same in every case. Use a longer-distance cable technology for the backbone (getting signal across the building), then use shorter coax runs for the last stretch to each antenna. The remote units at the far end are powered, not passive, so they can actively amplify the signal in their zone.
Some hybrid systems use fiber optic cable for the backbone. Others use standard Cat 6 ethernet cable, the same type of cable most buildings already have for their computer networks. The ethernet approach has become increasingly popular because it's cheaper, most electricians already know how to run it, many buildings already have unused cable in the walls and ceilings from previous network buildouts, and the system can deliver both signal and power to the remote units over the same cable. No need for someone to wire a separate power outlet at every antenna location.
The most common ethernet-based hybrid systems digitize the cell signal at a central unit, send it digitally over Cat 5e or Cat 6 ethernet cable to powered remote units throughout the building, and those remote units convert it back to RF and broadcast it through connected antennas. Because the signal travels digitally over the cable (not as raw RF like in passive DAS), there's essentially no signal loss between the central unit and the remote units regardless of cable length, up to about 330 feet on Cat 5e or 490 feet on Cat 6. Range extenders can double those distances, and an optional fiber module can push the system out to over a mile for campus-style deployments.
These systems also provide up to 100 dB of gain per carrier, which is significantly more than a standard commercial signal booster (typically 65 to 72 dB). That extra gain translates to better coverage per antenna, especially in buildings with heavy signal loss from materials like concrete or Low-E glass.
Where hybrid makes sense
Hybrid DAS fills the gap between passive and active. For buildings in the 100,000 to 500,000 square foot range (universities, large hotels, multi-building campuses, mid-size hospitals), it's often the sweet spot. It costs $1.00 to $2.00 per square foot, which is meaningfully cheaper than active DAS while handling buildings that would stretch passive DAS to its limits.
Most hybrid setups don't require carrier coordination, especially when the signal source is an off-air donor antenna (capturing tower signal) rather than a direct carrier feed. That means the timeline stays in the weeks range, not months.
The tradeoff
Hybrid is more complex to design than passive DAS. You're working with powered remote units and either fiber or ethernet infrastructure, which means the engineering takes more planning. Some hybrid systems are carrier-specific, meaning you configure the system for specific carriers rather than amplifying all carriers at once the way a wideband booster does. In practice, most systems support all three major carriers simultaneously, you just configure each one during setup.
Hybrid is still meaningfully simpler than active DAS, though, and the install timeline reflects that. A skilled team can have a hybrid system running in a few weeks versus the 6 to 18 months a full active DAS requires.
How to Figure Out What You Need
The decision comes down to a handful of practical questions.
Start with building size
Under 25,000 sq ft. A commercial signal booster with a few indoor antennas handles this. Most buildings in the US fall into this category. This is a days-to-install, under-$25,000 solution.
25,000 to 100,000 sq ft. Still passive DAS territory. A commercial amplifier with a network of splitters, couplers, and strategically placed antennas. Professional DAS solution design helps here, though the installation is still straightforward.
100,000 to 500,000 sq ft. This is the hybrid zone, or multi-amplifier passive DAS. The right answer depends on building layout, budget, and how complex the cable runs would be. If the building is relatively compact (a single large structure), passive DAS with multiple amplifiers can work beautifully. If it's spread across multiple buildings or wings, hybrid's fiber backbone makes more sense.
Over 500,000 sq ft. Active DAS, especially if you also have a high-density crowd situation. This is stadium, airport, and major campus territory.
Then consider user density
Most buildings don't have a capacity problem, they have a coverage problem. If you're an office with 50 to 500 people, a warehouse with a crew of 30, a hotel with 200 rooms, or a school with 1,000 students, you don't need to add network capacity. You need the existing signal to actually reach people's phones inside the building. Passive DAS handles this.
If you're a stadium with 70,000 fans or a convention center hosting 30,000 attendees, that's a capacity problem. Active DAS is the only technology that adds real network capacity alongside coverage.
Think about timeline and budget
If you need a fix this month, active DAS isn't an option. Carrier coordination alone adds a minimum of 6 months, and the total project from design to go-live typically takes a year or longer. Passive DAS installs in days to weeks. Hybrid takes a few weeks.
On budget, the math is stark. A 50,000 square foot building can be covered with passive DAS for roughly $15,000 to $50,000. Active DAS for that same building runs $100,000 to $500,000. For most building owners, that price gap is the entire conversation.
Public Safety Radio Requirements. Worth Knowing About
Here's something worth knowing if you own or manage a commercial building. Many local fire codes now require in-building radio coverage for first responders. The International Fire Code (Section 510) and NFPA 1225 mandate that buildings provide adequate radio signal for police, fire, and EMS communications inside the structure.
This is a completely separate system from commercial DAS (it operates on different frequencies for first responder radio networks), though it often gets designed and installed alongside a commercial signal solution. New construction over 50,000 square feet commonly triggers this requirement, and the penalties for non-compliance can be serious. If you're evaluating DAS for your building, ask your local fire marshal about ERRC (Emergency Responder Radio Coverage) requirements while you're at it.
Why Buildings Kill Cell Signal in the First Place
If you're wondering why this is even necessary, the answer is building materials. Modern construction is getting better at blocking cell signal, not worse.
|
Material |
How Much Signal It Blocks |
|---|---|
|
Drywall |
2 to 4 dB. Barely matters. |
|
Clear glass (single pane) |
2 to 3 dB. Minor. |
|
Low-E glass (energy-efficient) |
24 to 40 dB. This is the big one. |
|
Concrete (6 inches) |
10 to 19 dB. Serious. |
|
Metal walls or roofing |
32 to 50 dB. Almost total block. |
Low-E glass deserves special attention. Those energy-efficient windows going into every modern office building and hospital block over 99% of cellular signal. The metallic coating that reflects heat reflects radio waves right along with it. We talk to building owners constantly who can't figure out why their brand-new building has worse cell signal than the 40-year-old one next door, and this is almost always the answer.
Metal buildings (warehouses, factories, distribution centers) are essentially Faraday cages. Signal doesn't get in. If you're running a warehouse operation and your team can't use their phones or scanners inside, this is why. We've done metal warehouses, concrete office buildings, old brick hospitals, you name it. The building materials block cell signal, it just confirms that you need one.
The Bottom Line
If you're in a building under 100,000 square feet with dead zones and dropped calls, a commercial signal booster with a passive DAS antenna layout is almost certainly the right answer. It costs a fraction of active DAS, installs in days, works with all carriers automatically, and doesn't require a single call to a wireless carrier for approval.
If you're running a 300,000 square foot hospital campus or a multi-building university, hybrid DAS gives you the reach of fiber without the cost and complexity of a full active system.
If you're managing a stadium, airport, or convention center where tens of thousands of people need to be online simultaneously, active DAS is the only technology that can handle both the coverage and the capacity.
For most commercial buildings, though, the answer is simpler and cheaper than people expect. Give us a call at 1-888-974-8237 and we'll help you figure out what your building actually needs. We'll ask about your building, check the tower coverage in your area, and give you a straight recommendation and quote. No obligation, no pressure. We've designed systems for everything from 5,000 square foot offices to 60,000 square foot metal warehouses to 450,000 square foot hospitals, and the right answer is rarely the most expensive one.