BY MARY JANE DITTMAR
If this were a perfect world, perfect fireground communications would be a “given”: You would be able to rely on your radios 100 percent of the time. Alas, the world of the fireground is far from perfect, and no communications system can be guaranteed to be flawless. Moreover, a communications emergency can occur for a variety of reasons. A failure in fireground communications-even if it occurs only once in the lifetime of a system-could be fatal.
Therefore, the concepts of a backup plan, a plan B, redundancy, preplanning, training, and even innovation are as critical to successful fireground communications as to other fireground functions. But, this does not mean that you cannot achieve successful fireground communications.
“Even though 100 percent radio propagation (which is statistical in nature) is impossible to achieve, the on-scene commander should always be able to talk to the firefighter at the end of the hose or in the structure with a short-range (fireground) channel,” says Frederick G. Griffin, P.E., president of the Frederick G. Griffin, P.C., consulting firm based in Lynchburg, Virginia. Griffin, a registered professional consulting engineer, serves as a consultant for the Toledo (OH) Department of Fire and Rescue, which uses an 800 MHz trunked analog system.1
BEGIN WITH REALISTIC EXPECTATIONS
When beginning the process of searching for or designing a communications system, it might help to begin with realistic expectations.
“If you approach the implementation of a digital-based system methodically and without trying to apply analog experiences and expectations to the process, the transition to this technology can be made far less complicated,” says John M. Buckman, chief of the German Township (IN) Volunteer Fire Department in Evansville, Indiana, and president of the International Association of Fire Chiefs.
“Often, the assumption is that a fire department has 100-percent coverage with the system that is being replaced,” observes Leif Anderson, captain, technical services, Phoenix (AZ) Fire Department. “There is not a single fire service radio system today that has 100 percent coverage,” he says. “Firefighters know of many places within their city where they cannot talk with a fire radio.”
Phoenix, which currently uses a conventional radio system with voter/receivers on VHF and UHF, is in the process of developing an 800 MHz digital trunked system.
As Anderson sees it, “If you throw enough money at your radio system and you built unlimited sites in perfect locations and [with] the optimal signal strength, you get close to 100 percent coverage. The number of sites, their locations, and the signal strength generally determine the coverage,” he explains. However, he hastens to add that every municipality can spend only a designated amount of money for the project.
When working within these monetary parameters, Anderson says, fire departments need to design a modern system for exceptional coverage, at least 95 percent for analog [Editor’s note: and 97 percent for digital] by contract, and commit to installing bidirectional amplifiers in those buildings where testing reveals communications to be problematic. These kinds of improvements must be completed before the system is used for emergency situations where firefighters’ lives are on the line.
UNDERSTANDING THE TECHNOLOGY
Before looking at some of the specific challenges communication systems pose for fire departments, it would be helpful to review some of the major features of modern radio systems.2
•700 MHz and 800 MHz. The entire span of available radio frequencies is called “spectrum.” The 700 MHz and 800 MHz bands of spectrum tend to have better natural building penetration, which is a positive for firefighters. In addition, the Federal Communications Commission has moved nearly all existing commercial use of the 700 MHz band to other areas of the spectrum, dedicating large areas of the 700 MHz spectrum for public safety purposes, as is the 800 MHz spectrum.
Currently, public safety organizations are spread over at least 10 different bands of spectrum. No commercially available radio will cover all 10 bands (in fact, it would take 10 radios to communicate with all of the different public safety organizations-a negative for firefighters). The space available in the 700 MHz and 800 MHz bands makes it possible for multiple agencies to communicate with each other on demand and in real time (this is referred to as “interoperability”).
•Digital. In general, digital technology improves voice clarity. It is a more reliable technology and is easier to encrypt (if encryption is desired) than analog.
Digital systems work by converting a voice into binary information (1s and 0s) and then compressing it. Through modulation and encoding formats, the analog information is converted to digital data, compressed, and then converted back again, while still maintaining acceptable levels of voice quality. Digital technology sound is clearer and easier to understand than analog technology because background noise caused by signal fade is removed.
But, cautions Buckman, analog technology, with which the fire service is familiar, and digital technology couldn’t be more different solutions to fire departments’ ongoing communication challenges. As departments consider making the move to the powerful new digital technology, they will be challenged to open themselves up to new thinking. “Little, if any, of our experience in designing, implementing, and using analog systems will apply to this new technology,” he continues. “We must literally start from scratch.”
The basic complaint firefighters have about digital systems is its electronic digitized voice quality, explains Anderson. You can hear this on some digital cell phones when you are far from a tower or if the radio signal experiences interference (some people call it “ewoking”), he adds. Many choices are available when a system is being designed, Anderson points out. A less expensive system will yield lower-quality audio, he continues: “Both higher Delivered Audio Quality (DAQ) and lower Bit Error Rate (BER) values are equal to higher-quality audio.”
•Trunking. A trunk is simply a communications path. Its function is commonly described by way of analogies. As an example, imagine driving on a single-lane highway. The car in front of you stops. You have no choice but to stop and remain stopped until that driver starts up again. Now, envision driving on a multilane highway. If the driver in front of you stops his car, you can change lanes and pass the vehicle. A trunked system would bypass a nonavailable frequency and enable you to talk over another, available, one.
In a telephone system, each customer does not have a dedicated private line for every call. You dial, and the telephone company places your call on a trunk for the call’s duration. When the call is completed, the trunk becomes available to the next caller. Controllers, computer-switching equipment, at the telephone company automatically allocate the calls to the trunks. Within such a system, many users share a small number of trunks. As an example, several users can call Los Angeles at the same time; however, if too many users want to call there at the same time, the caller would generally be given the message “All circuits are busy” and would be asked to try the call again later. Trunked radio systems perform the same activity by giving the user a “bonk,” or tone, to let the user know the system is busy and to try again later.
In radio systems, trunking technology allows a large number of system users to share a small number of trunks (in this case, radio frequencies). The trunking technology is based on the following premises: (1) The percentage of time any individual user would require a trunk (frequency) is very small compared with the total time available, and (2) the probability that many users will require a trunk at the same time is exceedingly small.
When using a conventional radio system, each radio is operating on the same channel or frequency; therefore, each radio can talk unit-to-unit, and units within a building should be able to hear each other (even if the dispatcher, with a stronger receiver, cannot hear through the building).
When using a trunked radio system, each radio is set to a specific position (talkgroup); however, each push-to-talk is likely to occur on a different frequency (a controller puts your push-to-talk on the first available frequency, seamless to the user). In addition, trunked radio systems also require each portable radio to be able to connect with the radio system (similar to the way your cell phone blinks green once a second if it connects with the system and blinks red if it can’t connect). In other words, all trunked communications must go to the system (repeater) first before coming back to other units, even if the unit you are speaking with is standing next to you. This presents a potential problem to firefighters using a trunked system; you would not be able to communicate with a person standing next to you if your portable radio could not penetrate the building to reach the radio system (a nontrunked, or conventional, frequency is required to communicate radio-to-radio in this situation).
Several frequencies are assigned to each zone; those frequencies within each zone are available in a shared pool. When a user presses the push-to-talk button, the trunking system controller assigns a frequency to that talkgroup for the duration of the transmission. Once the transmission is over, the frequency goes back into the pool for reassignment. With a number of frequencies available, the likelihood that all of them would be unavailable at any one time is very small.
•Simulcast. The basic function of simulcast is to increase the range of a radio system. The main benefit to simulcast technology is the ability to hear tactical communications from great distances. In a nonsimulcast system, portable radio communications can travel only about four miles. A dispatch center with a powerful receiver must capture the voice, and the dispatcher must repeat it for all units outside the range of the initial portable radio to be heard. On the other hand, a simulcast system allows all portable radio users to hear all portable radio communications whenever they are within range of the radio network.
With this method, two or more transmitters (normally repeaters) on the same frequency are located at multiple high locations. The inputs of each repeater transmitter are tied together so they all transmit the same audio signal at the same time. In simulcast, no matter where a unit is within the system area, it will hear all transmissions on the talkgroup to which it is currently assigned. If a unit is close to one repeater, its receiver will be “captured” by the strong signal, and the received audio will be clear.
If, however, the unit is approximately equidistant from two or more repeaters, it will receive multiple signals. If these multiple signals are not exact in frequency, timing, the received audio can be garbled to the point of being unintelligible. This equidistant geographical area is called the “overlap” area.
Some rather expensive technical methods are used to control the transmitter frequency, audio characteristics, and delay so all transmitters transmit the exact same signal at exactly the same time.
On the repeater receive (or “talk-in”) side, all the receivers generally are fed into a device called a “voter” or “comparator.” The voter/comparator electronically checks (or compares) each receiver signal for accuracy of its data and then selects (or votes) the best signal to be sent to the dispatcher and rebroadcast. [The location of the simulcast controller (computer) and other equipment (including the voters) that makes simulcast possible is called the “prime site,” and it may or may not be located at one of the remote site locations.]
•Project 25 (P25). A P25 radio system has open architecture in that it has open interfaces and equipment definitions. P25 specifications cover many topics; however, a major purpose of P25 (at least as far as firefighters are concerned) is called common air interface, which allows any brand of P25 portable or mobile radio to interoperate on a P25 system. End users would not be restricted by the proprietary nature of a manufacturer’s radio system (sometimes referred to as closed architecture). Under P25 guidelines, nonproprietary codes are published so other manufacturers may use them to develop equipment.
Although P25 creates a standard set of features (basic requirements) that should be supported on any vendor’s equipment, each radio system manufacturer can expand on the standard features to include additional features that may be supported only on that manufacturer’s equipment. In other words, all P25 radios will perform all standard P25 capabilities, but if you choose one or more of these extra proprietary features, you may experience difficulties with interoperability.
P25 was created to ensure that all P25 radios will be compatible with those of other agencies (for interoperability), and yet those agencies will still retain the potential to purchase equipment from different manufacturers. (Fire service organizations rarely develop their infrastructure or purchase their radios with consideration for the cities and agencies with which they share borders or response areas. Therefore, each organization responds to a major emergency with a different noncompatible radio.)
At this time, Griffin points out, there is only one manufacturer of P25 equipment, and it has three systems in the process of being installed.
FIRE DEPARTMENT NEEDS ARE “UNIQUE”
The problems some fire departments have experienced with communications can be attributed to various causes. They range from the uniqueness of a fire department’s needs to inadequate participation in the planning process to the locality’s cutting system components after the system has been designed to weather. Some of these situations are avoidable; others must be anticipated and compensated for.
Learning the difference between these two categories and preparing accordingly begins with knowing exactly what your department’s needs are-and how to articulate those needs so they are fully understood by all parties involved in the design-planning phase, especially the manufacturer. “It is up to fire department officers and firefighters to describe their needs clearly, specifically, and in fire service terms,” says Buckman. “It is not helpful just to say that the radio system must work. What must the system be able to do? In what environments must it be able to perform? Specificity is absolutely fundamental,” Buckman stresses.
“If, for example, a portable radio must work effectively inside a hospital building, be prepared to provide examples of precisely where in the building the system must work,” Buckman says. You can determine your department’s specific needs by talking with your department members and networking with other fire departments that have gone to digital or are considering the shift now, Buckman suggests. “Digital systems are relatively new for the fire service, but there is a body of knowledge and experience available that a department can access,” he adds. “This is not the type of transition in which one should rely solely on his own experience.”
William Goldfeder, battalion chief of the Loveland-Symmes (OH) Fire District and Fire Engineering editorial advisory board member, sounds the following crucial reminder: “It is critical that radios work well under the worst conditions. Make sure those specifying your radios cross every ‘t’ and dot every ‘i’ to ensure your safety. It is worth the time. If you don’t, you are losing before the game even starts.”
Goldfeder continues: “Make sure the system is working before it is accepted and, even before that, make sure the specifications fully match firefighters’ requirements and needs. Make the manufacturer prove it, and not to some ‘suit’ in the budget office. Consider using your most experienced company fire officers (field officers, not the training bureau or others who don’t use the system under the toughest conditions), and have them participate in the testing of the system. They know where the system will be stressed and needed, the toughest spots, the deepest basements, the highest floors, the most remote rural areas, and so on. We are talking about a radio system that will be firefighters’ lifeline. It must be designed with that in mind.”
UNDERSTANDING THE MARKETPLACE
The digital systems are currently priced higher than the comparative analog systems by +15 to 20 percent on the infrastructure and by +90 to 100 percent on the subscriber units, according to Griffin.
CHALLENGES AND STRATEGIES
Fire departments facing communications challenges have employed different strategies, with varying degrees of results. A few examples follow.
Miami-Dade (FL) Fire Rescue
Miami-Dade County, Florida, has an 800 MHz trunked simulcast countywide system. Planning for the system began in 1993; the fire department was not involved in the initial planning process, according to Karl Oltz, division chief in charge of communications. The department, he said, gave its specifications at the end of the process and went on the system for eight days in June 1998.
The department experienced two major problems-radio failure and in-building coverage. “We theoretically couldn’t get the radios to work; the firefighting scenario is not a suitable environment for this system,” Oltz says. “It was not specifically built for firefighters. It worked satisfactorily under outside normal conditions, but the radios shorted out in hot, moist environments.”
And, he added, because of the trunked system, you sometimes had to wait to communicate until a line became free.
According to Oltz, there also was a problem with overlapping. Transmissions emanated from six towers. If a radio were sitting in the middle of two towers, no connection was made because the radio couldn’t select a tower. The remedy was to turn down the power. When that was done, the signal couldn’t penetrate buildings. It was especially hard for firefighters crawling on the floor inside the structures-the way firefighters normally fight fires-to receive messages.
The department went back to its conventional simplex, radio-to-radio UHF system (the dispatcher cannot hear the firefighters on the fireground). If the system’s signal can’t get inside, the department can now go radio-to-radio. The department uses the old system; the other agencies use the new one. With regard to interoperability, Oltz says his preference is to have face-to-face communications through an agency liaison in the command post.
Oltz’s offers advice to other fire departments: “Do your homework; decide what your requirements are before you choose a system. If you are going to buy a new system, you have to know the operational requirements, check out the vendor and equipment, and know the density of buildings in your geographical area.” The department hired an outside consultant after the fact, he says.
The radios, he explained, had never been tested in an atmosphere with temperatures of from 1,000
Ottawa, Canada3
In a move to consolidate local governments and to reduce municipal transfer payments, the Ontario, Canada, government mandated that, as of January 1, 2001, the 11 municipalities that constituted the former region of Ottawa-Carleton form a new city. Among other things, this involved integrating a minimum of 11 public safety networks (some municipalities had more than one); some smaller towns had systems that were 20 years old. Some departments were using VHF, others UHF. The Ottawa Transition Board, the provincial agency charged with creating the amalgamated city, hired the consulting firm Lapp-Hancock to assist with the project. Garry Rolston, working with Lapp-Hancock, said the fire department needs radios that work well indoors-not just in houses but also inside offices, malls, and parking garages.
He cites similar difficulties with the fire service in Vancouver. When the ambulance department was added to the police 800 MHz network in Vancouver, Rolston explains, the ambulance service was ecstatic. The coverage was exceptional. But, Rolston adds, when Vancouver Fire & Rescue moved onto the network, it encountered major problems in the downtown area. In some locations, the signal couldn’t get out. Vancouver Fire & Rescue turned to vehicular repeaters and installed transmitters on the trucks to boost the signals going to the firefighters’ radios, keeping the firefighters in touch with each other on the fireground.
Bidirectional repeaters may be another option in this situation, says Rolston. These repeaters are already mounted in the tunnels of Ottawa’s sewage treatment plant. The repeater system retransmits signals traveling in either direction. Both these options could potentially work for the Ottawa Fire Department, Rolston says.
The Ottawa Emergency Measures Committee is funding a study to determine whether the city’s 800 MHz network can serve all agencies, including the fire department. If not, the 800 MHz system would link the fire trucks to the city’s other services, and a second band would link firefighters to their vehicles. Another option would be to keep the fire agencies on separate frequencies as they are now, an arrangement Ottawa would prefer to abandon.
As of March 15, Rolston explained in an interview that Ottawa Fire Department mobile radios were still not operating on the 800 MHz system and that the fire trucks will be part of the trunked system. Rolston says consideration is being given to installing vehicular and/or on-site portable repeaters to improve fireground communications, but, he adds: “I don’t believe anyone is fully convinced that it’s the full solution. From the beginning, we have felt that the problems of the fire agency are unique. You cannot say a solution for police and ambulance services can be applied to fire.”
Meeting National Fire Protection Association (NFPA) 1221, Standard for the Installation, Maintenance, and Use of Emergency Services Communication Systems-1999, minimum requirements combined with the experience acquired may help the department to arrive at a satisfactory solution, Rolston says.
Delaware
The Claymont (DE) Fire Department is part of an 800 MHz statewide system. “We have had problems with the system since Day 1,” says Chief Eric J. Haley. On one occasion, firefighters were on a stairway in the fire structure. The fire spread to the stairs. Firefighters outside could not hear their radio message for help; it was unintelligible. Fortunately, the two firefighters were able to escape by way of a second-floor window that had been laddered.
In another instance, firefighters fell through the floor while fighting a house fire. Again, the firefighters outside the structure did not receive the call for help.
Haley describes the system as “very limited.” Firefighters talk on a conventional channel with a one-mile range. The message is unrepeated, and the panic button doesn’t work on the conventional channel.
An intelligent repeater didn’t help, Haley says: “The message has to go back to the dispatcher. We can’t hear him, and the dispatcher can’t hear what’s going on.”
Even the erection of a tower a couple of miles away didn’t help, according to Haley. There are plans to add another tower, but there is some disagreement in the community about whether the tower should be erected at the location considered as the optimal site for it. Some officials and citizens would prefer to see a park on that site. Haley says the tower may be erected on the site of second choice. At press time, town officials were holding hearings related to awarding a variance for putting up a new tower.
Maryland
In St. Mary’s County, Maryland, plans are underway to develop a countywide 800 MHz radio system. The county hired a consultant and established a large committee for the project, according to Charles Mattingly, past chief and president of the Hollywood (MD) Fire Department and president of the Maryland State Firemen’s Association. Five towers are presently transmitting in the county, and the dispatch center sits in the middle of the towers. Mattingly says there is too much traffic on the 800 MHz frequency. The county is hoping it can go on the 700 MHz frequency instead. The more towers, the better, Mattingly says, but it takes time and money.
In the meantime, all fire officers have portable radios with four channels; when calls back up, they go to a different channel.
Calvert County, Maryland, was experiencing an intermittent loss of calls at press time, according to Don Hall of the county’s Federal Emergency Management Agency office. He said he has received complaints about incomplete messages or intermittent missed calls and noted that there is interference on the county’s 800 MHz simulcast radio system. The cause of the problem had not been determined at press time. One explanation proposed was Nextel’s erection of a tower on a water tank next to the fire station; the towers appear to be interfering with each other.
Fire Department of New York (FDNY)
The topic of fire department communications in New York City was widely covered in the press even before the September 11, 2001, attacks on the World Trade Center (WTC). The city had issued its new digital radios to firefighters and almost immediately began experiencing communications difficulties on the fireground. Ultimately, former Fire Commissioner Thomas Von Essen withdrew the radios from service. The radios were recalled last spring and were reprogrammed from digital to analog mode by the manufacturer and an FDNY communications technician. They were to undergo testing at the city’s fire academy. Then, the attacks on the WTC occurred.
Deputy Commissioner Francis Gribbon says the radios are currently being tested in simulated fire scenarios at the training academy.
There were reports that the fire department’s radio failed at the WTC and some firefighters did not hear an order to evacuate the north tower. Rudy Giuliani, then the mayor of New York City, said at the time that the extent of the problem had not been determined, but communication problems would not be unexpected in that situation. Giuliani added that some firefighters with whom he spoke did hear the evacuation order. Reportedly, a repeater installed in the WTC to boost the radio signal after the 1993 attack was damaged by falling debris.4
Gribbon said in an interview that the department has hired a consulting firm to assist it in analyzing and evaluating how the department’s communications performed during the World Trade Center operations; the study will include communications at independent locations and cover analog and digital modalities. Another objective of the study will be to determine what will work best on the fireground. The differences between analog and digital must be addressed through training, usage, and technology itself, Gribbon adds.
Part of the problem, says Captain Peter Gorman, president of the FDNY Uniformed Fire Officers Association, is that the chief of the department never saw the radios and members of the command structure never tested them. “We worked with the radios for two weeks and received 15 reports of lost messages from incident commanders, among them one from a firefighter trapped in a basement.” The union is part of the current testing and evaluation phase.
FDNY uses an apparatus-mounted system for communicating with the central dispatcher and radios (handie-talkies) for communicating on the fireground. An internal repeater system is used for high-rise buildings; internal repeaters have been installed in certain strategic locations such as train stations and some high-rise buildings. There was a repeater in the World Trade Center. Battalion chiefs’ cars have a separate crossband repeater system onboard; the chief’s car has a booster signal, according to Gorman.
The city has approximately 600 buildings that are higher than 20 stories, and only about a handful of them have repeaters, Gribbon explains. He adds that the department has asked the Federal Emergency Management Agency for $60 million to install repeaters in these high-rise buildings.
Cedar Hammock (FL) Fire Rescue
Cedar Hammock Fire Rescue in Manatee County, Florida, uses an 800 MHz analog trunked system, as do most county and emergency agencies in Manatee County, says Battalion Chief Leigh Hollins.
In “Digital vs. Analog Radio Systems” (Roundtable, November 2001), Hollins reported the following: All of the 911 station notification and dispatch services are provided by the Manatee County Department of Public Safety, through the Emergency Communications Center (ECC). The district has communication “dead spots,” and there are buildings where the portable radios do not perform well inside.
According to Hollins, the department has had limited success by switching over to the conventional simplex radio-to-radio communications when a problem arises. But, changing the radio to the simplex mode is not easy. All on the apparatus must know which knobs to turn or which buttons to push, or an individual familiar with the various mobile radios has to make the rounds and change all apparatus radios, including the portables, to simplex mode. Interior crews would find it extremely difficult to do so in darkness and with gloves on. In addition, when in the simplex mode, the emergency communications center cannot hear the firefighters on the fireground, and the firefighters cannot hear the dispatcher.
The department has also purchased and used-with limited success-a com-link to address dead spots or dead buildings. The link allows communications between two different systems, such as 800 MHz and VHF systems or the analog and simplex modes, or the analog and digital modes. The com-links must be custom engineered.
Cedar Hammock, as most other fire departments in the country, has communications issues that cannot always be solved, Hollins says. The department uses alternative communications strategies to address problem areas most prone to losing radio communications. They may include providing SCBAs with integrated PASS; verifying that every firefighter entering the building has his PASS turned on, assigning an officer at the entry door to “listen” for trouble and “shout” instructions, establishing an independent (nonradio) “evacuate” signal, and training personnel to think outside the box in case radio communications are lost.
Washington, D.C.
In Washington, D.C., the fire department switched to an 800 MHz trunked system expecting expanded communications capabilities, enhanced incident command, and the ability to communicate with suburban fire departments and other emergency agencies, explained Battalion Chief Richard G. Sterne, of the District of Columbia Fire Department, in the November 2001 Roundtable on radio communications. Instead, he asserted, “The new radios were my worst nightmare come true. We did not get what was promised.”
Among the problems he listed were the following. Firefighters operating in large buildings routinely get “honked out,” as do units covering the rear position in the alley behind large buildings on the fireground. When the reception area is borderline, the radios “think” they are in range, but what comes out of the speaker is unintelligible gibberish.
In addition, the system often does not work in the basement of two-story rowhouses or in some underground parking levels. In these instances, the radio does not even honk; therefore, the inside firefighter mistakenly thinks he is communicating.
When this occurs, Sterne adds, the department switches to the one analog talk-around channel available. Units are assigned an operating or tactical channel when dispatched to an alarm; mobile and portable radios are switched to the assigned channel while responding. The chief carries an extra portable radio and monitors the analog talk-around channel as well as the assigned digital tactical channel-and he talks to the dispatcher over another channel. Since all these channels must be covered, the chief’s aide must assist with communications and must stay in the vehicle instead of tending to tasks such as reconnaissance of the building and assessing fire conditions.
According to Alan Etter, public information officer for the D.C. Fire Department, the 800 MHz system had been in development for 10 years. “At a certain point in the development process,” he explains, “the previous administration decided basically to gut the innards of the system. They cut the appropriation for the system from $65 million to $6 million.” The system, Etter explains, “would be optimized with 19 antennas at strategic sites; they gave us four antennas. The system could work better if we added antenna sites.”
As an alternative, Etter notes, the city built an analog channel into the 15 digital channels. One analog talk-around channel was reserved for subsurfaces and tall buildings. There are plans to test some portable antennas, which would act as a relay, in the command vehicle. In the meantime, Etter explains, five engines are dispatched for a regular box alarm. The fifth engine is used as a communications vehicle; messages are relayed using portable radios.
Communications with firefighters inside the fire structure are maintained with a chain of radios. When the firefighters are in a basement, the number of portable radios is increased or, even better, the talk-around analog channel is used, Etter says.
AVOIDING PITFALLS IN The Planning Process
When planning for a communications system, the department and the vendor should have the same degree of capability, experience, and time, to ensure parity on both sides of the table, says Griffin. “All product lines are vendor proprietary; therefore, the purchaser is entering into what is akin to a franchising arrangement-not a contracting process-for 10 to 15 years,” cautions Griffin. “In general,” he says, “fire departments should be careful about buying into other contracts, state purchase contracts, and sole source or designated vendor relationships.”
Griffin offers the following suggestions to fire departments engaged in planning for a new communications system:
- Ensure that all parties involved fully understand all aspects of the project.
- Hold monthly project meetings during the implementation period.
- Document all changes that must be made.
- Keep the project team intact until all changes have been made and all claims and warranty agreements have been resolved to the department’s satisfaction.
- Devise a testing plan. A group that represents the vendor, a consultant, and the users-dispatch, firefighters, as well as other agencies-should coordinate the testing procedure to ensure adequate coverage and audio quality. The testing should be completed before a considerable portion of the system is positioned and functional.
“Do not lock into a vendor early by putting insufficient sites just to get a system up with the anticipation of fixing it later,” cautions Griffin. “Do it right the first time, or do not do it at all. A new computer trunked radio system is an embedded high-capital-cost utility and should be appropriated in that manner.”
You can save time and money and minimize the potential for failure by consulting with other agencies in your locality, says FDNY’s Gorman. He says that had the fire department spoken with the city’s police department beforehand, it would have learned that the police had experienced problems with digital radios. The police had tried the system and abandoned it. You can get valuable information such as this from your local agencies, Gorman says. “Talk with them during your planning process. Sometimes, the information that may help you is available in another department in your locality.”
ANATOMY OF ONE DEPARTMENT’S PLANNING/DESIGN PROCESS
Following is an overview of the Phoenix (AZ) Fire Department’s planning/design process, as reported by Captain Leif Anderson, a firefighter assigned to Technical Services. The department is switching from an analog voter/receiver radio system, primarily on VHF frequencies, to an 800 MHz P25 digital trunked system. The Phoenix system, known as the Phoenix Regional Wireless Network (PRWN), will be interconnected with an identical project in Mesa, Arizona. The PRWN is designed to support public safety, public works, and the area’s international airport (Phoenix Sky Harbor).
Phoenix Fire
The Phoenix Fire Department dispatches for 19 fire service agencies within Maricopa County. Most of these agencies border Phoenix and share automatic-aid agreements with the city. All operate on the same radio frequencies, and, regardless of where the call for help originates, the closest appropriate fire truck(s) will respond.
Specifically, the city of Phoenix is more than 500 square miles in size and has a population of approximately 1.5 million people. The Phoenix Fire Department has 1,325 sworn members and responded to 133,458 incidents last year.
Interoperability is a key feature of any modern radio system. The PRWN will improve current automatic-aid agreements and also allow Phoenix Fire to interoperate with the East Valley fire departments, police, and municipal workers.
Planning History
In the late 1980s and the early 1990s, the city of Phoenix hired separate consultants to review choices for a new radio system. In the late 1990s, Phoenix consolidated the PRWN with the Mesa TOPAZ project, creating a regional system with wide area coverage. In 2000, the project received council authorization, and the detailed design was completed. Staging tests were completed at the end of 2000; actual installation began earlier this year. A separate request for proposal (contract) was issued for the subscriber equipment (portable/mobile radios) to increase competition and allow more time for product development.
Features
The PRWN system was designed to include the following features: 800 MHz frequencies, digital voice technology, trunking technology, simulcast technology, and P25 compatibility.
The PRWN is actually several trunked radio systems linked together. These systems (commonly called “zones”) provide radio coverage in a specific geographical area. The PRWN is made up four such zones with interconnection to the Mesa TOPAZ zone.
Project Organization
As Phoenix began to research trunked radio systems around the country, the fire department became concerned that it needed an advocate within the management of the project. A comprehensive organization of project teams and a management system were already in place. A project manager, who reports to a Steering Committee, basically manages the project. Other important project teams include a Transition Managers Committee (department managers) and a Technical Team (radio systems specialists). The fire and police departments wanted a stronger role in the project development and wanted to provide more input into the day-to-day events. They formally requested to be involved. This led to the development of a new committee, called the Public Safety Steering Committee. It is comprised of representatives from both the fire and police departments and an equal number of union representatives. This committee has the authority to bring issues before the Steering Committee. Fire department members were also assigned to the Steering Committee, the Transition Managers Committee, the Technical Team, and the User Needs Subscriber Committee.
System Design
The PRWN was designed to cover 95 percent of Phoenix’s total service area. It was designed with an initial Grade of Service (GOS) of 5 percent. A 5 percent GOS is basically equal to a 95 percent chance of getting through when you push-to-talk under the designed load. Public Safety Steering Committee input led to a revised GOS of 98 percent with a revised design load based on user input, actual data, and computer simulations.
The PRWN was designed to provide in-building coverage. Zero dB (0 dB) represents a signal strength that would result in a 95 percent reliable signal. The PRWN provides +12 dB to residential areas (16 times greater than baseline), +17 dB to moderately dense industrial areas (60 times greater than baseline), and +23 dB to dense or high-rise areas (250 times greater than baseline). In addition, the project is budgeted to provide extensive building treatment through the use of bidirectional amplifiers, as needed, based on system testing.
The PRWN system is designed to have a DAQ of 3.4. Committee members believe this level of digital sound quality will decrease the number of speaking/listening errors, improving the ability to communicate. Systems with a DAQ of less than 2.5 to 3.0 may experience the voice digitizing more frequently.
The PRWN and Mesa TOPAZ are divided into five zones comprising more than 35 sites. Two zones lie directly on top of each other and cover the city of Phoenix proper. Zone “A” supports police and some municipal activity, Zone “B” supports fire and some municipal activity, Zone “C” covers the southeast valley, Zone “D” covers the east valley, and Zone “E” covers the west valley.
Guard Channel
A guard channel is a “car-to-car” nontrunked/conventional channel that bypasses the trunked system when firefighters are not able to communicate on the trunked system. A guard channel allows firefighters who are reasonably close to each other to communicate directly with each other in cases where their portable radios cannot reach the trunked system.
The PRWN was designed to provide radio coverage on the street and in-building; however, some areas may not be covered by the trunked system. To ensure that our firefighters always have radio communications, we have proposed to use NPSPAC mutual-aid frequencies.
Since the guard channel is not trunked, the dispatch center may not be able to monitor the radio traffic that may occur. To enhance firefighter safety, a network of receivers could be placed on the guard channel. The audio from these receivers would be routed to the dispatch center by phone lines. The Receiver Voter System (RVS) would select the best signal and route it to the dispatch console. This concept is the basis of the current radio system.
Motorola has recently announced an 800 MHz in-band repeater. This repeater would allow the guard channel (nontrunked/conventional) to be repeated in the trunked system. The repeaters could be mounted on fire apparatus. If multiple units arrive on-scene during an incident, the repeaters would be able to sense other repeaters. This feature prevents interference from multiple units. These units can also be controlled from the dispatch center. The ability to repeat the conventional channel to the trunked system is a safety enhancement. It will allow the dispatch center to monitor the nontrunked/conventional channel and enable it to patch it to the assigned tactical channel.
Status of the PRWN
The equipment was constructed and assembled in Schaumburg, Illinois. It was disassembled and shipped to Phoenix, where it is currently being installed at the various site locations. Current estimates indicate the system will be installed and ready before the end of the year. However, Phoenix’s acceptance of the system is not scheduled to occur until June 2003. Beginning in July 2003, the following phases will be implemented: a burn-in period, test loading, various system testing, and actual use loading. The request for proposal for subscriber equipment (a separate contract from the design/infrastructure) is currently being written. Equipment installation department-by-department transition will begin soon after all testing is performed.
ADDITIONAL RECOMMENDATIONS
- Storms and other natural disasters can knock out a communications system. So can improper maintenance. In the state of Maryland, for example, a circuit breaker blew out in a radio signal booster, resulting in firefighters inside a burning house failing to hear an emergency evacuation alert. There was no alarm to indicate to local or state officials that the communication system was down. When planning for your system, ask if there is an alarm system that warns when there is no communications, and establish a plan to ensure that the equipment-including the alarm system-will be properly maintained and regularly inspected for functionality.
- This cannot be said too many times: To ensure communication in on-site buildings with dead spots, build some form of direct walkie-talkie compatibility into your system. In the traditional conventional systems, this might be a specific fireground channel or a talkaround channel that uses the portable receiver frequency. All newer, properly designed trunked systems should have this capability. The product lines of the major suppliers have this capability if it is specified and implemented, stresses Griffin.
- If you are on a countywide or statewide system, make sure you establish a committee to work with the government agency concerning your communications needs.
- Technology is ahead of applications in the fire service, FDNY’s Gorman points out. “When you lose a signal in a digital system, it drops off completely; in the analog system, you would get the message even if there’s static,” he explains.
- A fire department should develop positions on the project committees so its members can serve as department advocates. In Phoenix, Anderson says, research has shown that a lack of user input and involvement directly led to problems. Each department needs to have full-time representatives who can track the project, participate in decision making, and forecast risk assessment, he adds. “Somebody needs to be there to force the technical people to translate what they are saying and doing into firefighter-friendly language. It will slow them down but improve the project by eliminating problems before they occur,” Anderson says.
Endnotes
- Some suggestions for conducting a search for a public safety consultant can be found in “Public Safety Consultants,” by Frederick G. Griffin, P.E., 9-1-1 Magazine, Nov/Dec 1997, 36-38. Griffin may be reached by e-mail at [email protected]. You may also consult the Web site www.fggpc.com.
- Source for the descriptions is Leif Anderson, captain, technical services, Phoenix (AZ) Fire Department. He may be reached at [email protected].
- “Ottawa’s communications consomm
MARY JANE DITTMAR is senior associate editor of Fire Engineering. Prior to joining the Fire Engineering staff in 1981, she had served as editor of a trade journal in the health/nutrition industry and headed MJD Promotional Services. She has a bachelor’s degree in English/journalism and a master’s degree in communications arts.
