Does Your Building Need a Passive or Active DAS?

Posted on October 29, 2021October 29, 2021 by rfsolutions

Does Your Building Need a Passive or Active DAS?

At RF Solutions, we design public safety and cellular enhancement distributed antenna systems (DAS) for high-rise buildings and other large venues. Cell DAS installations are almost always active solutions, but public safety systems can be passive, active, or hybrid. Before we begin to design a system, there are many factors to be considered. The optimal system design will depend on the unique characteristics of the building in which it will live and the communications requirements of local first responders. These factors include the coverage area, the design of the building, the building materials, signal source(s), and the project timeline. Once we’ve gathered the building particulars, we can determine whether the system should be passive, active, or a hybrid of the two.

A passive system uses “passive” components like coaxial cable and splitters to distribute RF signals. Using coax to distribute the signal will produce a higher signal loss than an active solution. The further the antennas are located from the head end, the higher the signal loss, which results in lower downlink output power. These restrictions are the reasons why a passive system may not be appropriate for a specific building.

An active system uses fiber optic cable to distribute signal between a centralized signal source (head end) and remote nodes placed strategically throughout the building. A hybrid solution is built upon an active system using fiber to distribute signal but relies on a passive DAS design for most signal distribution. Buildings with unique challenges might benefit from a hybrid solution.

When determining if a building needs an active system, there is no magic size (square footage) number per se, but it usually falls around the 1million sq. ft. mark. However, there are many sub-1mm sq ft buildings where we’d choose an active system. You could easily have a 750,000 sq ft legacy hospital facility with dense walls and floors that will need to use an active system to meet the required coverage because RF signals will have poor penetration. Many older (pre-war) buildings present these same issues. A new, smaller building might require an active system if it’s steel reinforced. A warehouse with heavy shelving and dense stored materials may need one as well. Conversely, a +1mm sq. ft football stadium might not require an active system due to the open architecture. That’s why it’s so important to understand the propagation characteristics, like wall density, building composition, and building age, before starting the design.

You might ask why not always use an active solution? The simple answer is cost. Active systems are expensive, but an added benefit of using a fiber DAS is that it’s future-proofed. Using fiber provides the unique ability to upgrade when new technologies or frequencies must be added to a system. Converting the radio signals to light over fiber allows the use of multiple distribution points (nodes) with little or no loss in the transport system.

So, you see, there isn’t a hard and fast rule you can use to determine which way to go with your public safety DAS but knowing all the building’s characteristics and technology requirements beforehand will steer you in the right direction.

The Call for Robust, Reliable Communications for First Responders Nationwide

Posted on January 28, 2020July 21, 2021 by rfsolutions

The Call for Robust, Reliable Communications for First Responders Nationwide

In 2005, the US National Institute of Standards and Technology (NIST) issued its Final Report on the Collapse of the World Trade Center Towers (NCSTAR1). This comprehensive report included 30 detailed recommendations for improving the safety of buildings, occupants, and emergency responders. One of the essential elements addressed the need for robust, reliable radio communications for first responders. The general public had a misconception that such in-building coverage already existed when, in fact, it was inadequate in almost every circumstance.

National Standards Created for ERRCS

In response to this report two standards organizations, the International Code Council (ICC) and the National Fire Protection Association (NFPA), created standards for the design and installation of Emergency Responder Radio Communications Systems (ERRCS). These standards are similar in scope and are incorporated into the statewide building “Fire Code.” A few major cities (such as NYC, Boston, Philadelphia, District of Columbia) have developed their own, more stringent requirements based on comprehensive planning for various response scenarios. Outside of these cities, the national codes empower local AHJs (Agencies Having Jurisdiction) – typically the local fire departments – to regulate specific in-building radio coverage. These regulations are based on planned first responder operations within their communities. Under the enacted codes, building owners are responsible for installing infrastructure within their buildings to meet the requirements set forth by the local AHJ.

A Failure to Communicate

Public Safety Agencies (PSA) typically have their own radio communications system for coverage throughout their area of operation. Unfortunately, radio signals do not penetrate buildings well. Large buildings typically have many “dead areas,” especially in the center of the building, on floors housing mechanical and electrical equipment, and in below-ground levels. These are critical areas where firefighters and other first responders must have reliable wireless communications, in addition to areas that have incidental coverage from transmitter sites outside of the building. It’s a fact; failure to communicate effectively puts lives at risk.

We Have the Solution

When RF Solutions starts a project, we begin by first consulting with the AHJ and any other known stakeholders. We identify the types of communication that may be required – internal communications between responders inside the building, and external communications to allow responders to talk back to their dispatcher. Once the specific requirements are confirmed, it is necessary to visit the actual building’s location and measure signal levels for each system to determine what enhancements (if any) are required. A 3-dimensional propagation model of the building is constructed to optimize antenna placement and determine what signal amplification is needed and where to locate the amplification equipment. Our experienced and certified engineers perform design work using iBwave software. iBwave is the global industry-standard technology for developing accurate wireless propagation. The result is an efficient design which complies with local, state, and national code requirements, and ensures that no “dead areas” will hinder effective communication.

Leaders in the Public Safety Field

RF Solutions was founded in 2016 by experienced telecom professionals who wanted to use the best available technology and engineering services to make buildings safer and to protect critical infrastructure. Starting in the New York Metro area and branching out to adjoining states and beyond, we have received recognition for our leadership in the industry. In New York City and other locations with more stringent codes, we adhere to the established requirements and processes. In all other instances, RF Solutions takes a consultative approach because each municipality has a unique combination of first responder communications systems utilizing various frequencies and technologies. Additionally, every building has its requirements depending on the building’s construction and its location relative to transmitter sites of these systems.

RF Solutions Serves New Jersey and Beyond

As a result of our strict adherence to local and state ordinances, we have received many Letters of Authorization from FDNY as well as approval for numerous systems in New Jersey. Our systems are often approved on the first inspection, allowing the owners to obtain their Certificates of Occupancy without delay. RF Solutions currently has over a hundred projects underway in the Tri-State Metropolitan Area including overseeing one of the largest two-way radio projects in Manhattan and consulting on a large and complex Emergency Responder Radio Communications System in New Jersey.