BDA systems: the equipment that fixes in-building radio coverage.
A bi-directional amplifier is what gets installed when a building cannot pass its radio coverage test. This page covers what is in one, the choice between Class A and Class B, and what the installation actually involves.
- Testing that tells you whether you even need a system
- Design and installation by our own crew
- Yearly testing after, so you stay compliant
Ask us about your building
Tell us where it is and what it is. We’ll tell you what’s required and what testing costs. No obligation.
A BDA is an amplifier, plus everything that makes it legal
BDA stands for bi-directional amplifier. On its own it is one box on a wall. A system that passes inspection is that box plus the antenna that feeds it, the cabling that distributes it, the battery that keeps it alive and the panel that reports when something is wrong.
Donor antenna
On the roof, aimed at the public safety tower. It picks up the signal the building is blocking. Aiming it is survey work, not guesswork — the wrong heading undoes everything downstream.
The amplifier
The BDA itself, in a NEMA-rated enclosure. It boosts the signal in both directions: tower to handheld, and handheld back out to the tower.
Distributed antennas
Coax and antennas carrying the signal to every floor, stairwell, elevator lobby and basement. This is most of the labour on a job.
Battery backup
Generally 12 hours of standby, in a monitored enclosure, so the system survives the power loss that often accompanies the emergency.
Annunciator panel
Usually in the fire command centre. It reports antenna failure, amplifier failure, low battery — so a dead system announces itself instead of being discovered during a fire.
UL 2524 listing
The product standard for this equipment. Unlisted hardware fails inspection regardless of how well it performs.
Class A or Class B, and why it matters to you
The distinction is the one specification question worth understanding before you buy, because it decides whether your system can be fixed when the radio landscape changes around it.
Class A — channelised
Amplifies only the specific channels your responders use. Cleaner, far less likely to interfere with the public safety network, and easier to get approved. Costs more.
Class B — broadband
Amplifies the whole band. Cheaper, quicker to configure, but it amplifies everything in the band including noise, and some jurisdictions will not accept it.
What we do
We size it to the building and to what the local system actually uses. A Class B on a site that needed Class A is the kind of saving that gets paid back at the inspection.
What the work actually looks like on site
Mostly it is cabling. The schedule is driven by access to risers, stairwells and occupied floors far more than by the equipment itself.
Survey and test
Before anything is specified, the building is measured. This tells us how much gain is needed and where the antennas have to go.
Design and submittal
Drawings, equipment schedule and the cut sheets your fire official will want to see. We do not handle permitting in house, but we provide the documentation your permit needs.
Rough-in and install
Our own crew — not subcontractors. Coax, antennas, the amplifier, the battery enclosure and the annunciator, co-ordinated around whoever else is in the building.
Commission and certify
The installed system is tested against the same grid as the original survey. That comparison is the proof it works.
Tell us about the building.
We’ll tell you what’s required and what it costs to find out. No obligation.
What people ask us about this
In everyday use, yes. ERRC is the requirement, BDA is the main piece of equipment used to meet it, and public safety DAS is another name for the same installation. If someone quoted you for one and someone else specified the other, they are talking about the same job.
It depends on the size of the building, how many floors need covering and how strong the outside signal is — a weak donor signal means more equipment. Anyone giving a firm number before testing is guessing. We price it once the test says what is actually needed.
Class A amplifies only the specific channels your responders use. Class B amplifies the whole band. Class A is cleaner, less likely to interfere with the public safety network and easier to get approved; Class B is cheaper. Some jurisdictions will not accept Class B at all.
Yes. UL 2524 is the product standard for this equipment, and hardware that is not listed to it will not be accepted at inspection no matter how it performs on the day.
No. Design and installation are done by our own crew. It is the main reason we can stand behind the commissioning results rather than pointing at someone else when a system does not perform.
A badly configured one can. An amplifier set too broad or driven too hard can raise the noise floor for the very network it is meant to support, which is why jurisdictions care so much about how these are specified and commissioned. It is also the practical argument for Class A over Class B — amplifying only the channels in use rather than the whole band. The protection is measurement: the finished system is commissioned against the same grid used to test the building, so what it actually does is documented rather than assumed.
Most of the work is cable — risers, ceilings, stairwells. The equipment itself goes in quickly. In an occupied building the schedule is driven by access rather than by the installation: which areas we can be in, at what hours, and how much notice tenants need. It is worth raising at the survey, because it changes the sequence of the work more than it changes the price.