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DAS Coverage Testing — Why You Should Do it


Coverage testing is important to make sure buildings have the wireless coverage they need. It can help determine whether or not a distributed antenna system (DAS) needs to be installed to improve coverage, as well as serve as a baseline test for pre and post DAS installation performance.

Buildings throughout the country are getting DAS’ installed, or may already have them to remediate coverage issues. Buildings of different sizes and types have to worry about public safety radio and cellular coverage for code compliance, safety, and convenience reasons.

Here, we’ll dive deeper into what coverage testing is, how it’s done, who needs it, and why you should do it.

DAS and Coverage Testing

Businesses are concerned with in-building wireless coverage, as concrete, metal, and low-E glass will decrease the signal that you would get outside. Coverage testing is the act of measuring signal strength and quality of radio frequencies, often testing for wireless cellular and radio coverage. These measurements are then processed by software into reports for easier consumption.

For public safety radio coverage, coverage testing is often a requirement by the Authority Having Jurisdiction, (AHJ) such as a Fire Marshal, in order to approve a building inspection as a part of fire code. This is often referred to as Emergency Responder Radio Coverage (ERRC) testing. This ensures that first responders have the ability to receive and transmit critical communication when they are in your facility. Most public safety radio tests involve creating a grid of 20 or 40 squares per floor in a building, after which a signal strength measurement is taken within each of the grids.

Some common elements across multiple fire codes include:

  • Signal strength measurement of at least -95 dBm is considered passing in that grid.

  • Passing coverage must be in 90% of the squares.

  • If adjacent squares have failing coverage, a DAS will be required.

If the building fails the coverage test, a DAS will need to be installed to remediate the coverage issues. If the building passes the coverage test, the AHJ will often approve the building without needing any additional enhancements.*

*Some jurisdictions require a DAS to be installed based on square footage or other parameters regardless of existing in-building coverage.

Cellular coverage, on the other hand, is not a building code requirement. And most “evidence” of poor coverage is usually anecdotal. “My Verizon signal is terrible in the warehouse!” Cellular coverage can be very complex due to multiple carriers, multiple frequency bands used by each carrier, and multiple devices that may utilize different frequencies or have differing performance. Cellular coverage testing using professional grade test equipment is the only way to get real scientific data across multiple carriers, and all bands, providing a holistic view of your in-building coverage.

How Is Coverage Testing Done?

Day Wireless Systems provides coverage testing services using sophisticated equipment and software from PCTEL. Inspection of a property is performed on foot, with equipment worn in a backpack in what’s referred to as the “walk test.” The equipment is capable of measuring many data sets, but most important to us is RSRP and SINR.

Reference Signals Received Power (RSRP) is the signal strength, while Signal to Interference Ratio (SINR) is an indicator of signal quality. Thousands of readings are taken at numerous locations within a building, after which the data is processed.

Reports can be created to give the customer easily digestible maps, charts, and graphs of what exists “organically” and what could be done to remediate poor coverage areas. By having a complete picture of what exists, you don’t need to rely on “cookie cutter” designs for remediating coverage. You know exactly what, and where you need amplification. Therefore you save time and headaches by not over or under-designing a system.

The beauty of the testing hardware & software we use is it has the ability to measure all cellular carriers & bands (including 5G on some of our newer test sets), private land mobile radio, and public safety radio all during the same walk test. Many of our customers have an immediate need for one of these tests, but are able to test the other signals at the same time!

Why Is Coverage Testing Important?

Annual (or sometimes biannual) coverage testing of Emergency Responder Radio Coverage is already a requirement in municipalities where customers have a Public Safety DAS installed. It is a life safety issue for first responders to have the communication lifeline they need. Regular testing ensures that the DAS is working as it should.

As for cellular, poor coverage was once something you just had to deal with. Today, your tenants, employees, and customers all have the expectation that their device is going to work for convenience and safety reasons. Having professional cellular testing done gives you a holistic view of your organic cellular coverage and provides you a baseline of scientific data, not anecdotal evidence.

Land Mobile Radio (LMR) is used by many businesses for their on-site communication, yet very few have ever had their radio coverage mapped and tested. LMR is a key tool used for productivity and safety of workers.

Coverage testing can determine exactly where problem areas lie and helps integrators like Day Wireless with hard data so that we can provide the appropriately designed solutions instead of cookie cutter ones. This saves the customer time, money, and provides a better working system.

Want to learn more about our in-building coverage testing service?


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