P25 Radios Make Strides Toward Interoperability

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The EF Johnson 5100ES series is offered in colors to distinguish between user functions.
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A firefighter listens to a handset transmission on a Harris Public Safety P25-capable radio prior to making an attack.
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Vertex Standard offers P25 portable radios in its VX 820 and VX 920 models, both in multiband, Mil Spec submersible configurations.
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The Thales Liberty multiband land mobile radio covers the FCC approved public safety spectrum.

Most handheld radios made for the fire service today owe their designs to a complex, ambitious endeavor called Project 25 that was created 20 years ago to improve communication among public safety agencies operating on different systems.

Making progress toward that goal of interoperability has been a major undertaking. It depended on cooperation among police, fire and emergency agencies, state and federal communications officials and competing manufacturers with their proprietary technologies to develop standards for digital two-way wireless products that everyone could accept.

In the years after Project 25 was established, a sense of urgency grew out of communications difficulties encountered by agencies responding to the two most deadly incidents of terrorism on American soil – the 1995 bombing of the Alfred P. Murrah Federal Building in Oklahoma City and the Sept. 11, 2001 suicide attacks by al-Quaida.

Not Smart Phones

Today Project 25 has completed one set of standards and has entered into a second phase. While P25 handheld portable radios have robust chips and software, as well as added displays and data handling capabilities, they are not in the same league as smart phones. That type of additional potential would require the development of software and interfaces to link portables to the Internet. But radio makers caution that putting too much information capability on a portable might distract a firefighter from the radio’s chief function – voice communication.
It is difficult to assess the popularity of P25 radios, according to manufacturers, because of their higher cost compared to other models and the vastly different requirements of career and volunteer departments.

Steve Frackleton, director of marketing for Harris Public Safety and Professional Communications, said his company has been active in developing Project 25 phase 1 and 2 standards and offers a full line of P25 compliant networks and products.

“From a portable standpoint of P25-capable radios, we’ve been shipping our P7100 for a number of years,” he said, “and since 2008 have offered the Unity XG 100 that’s capable of both analog and P25 digital communication. It complies with the [military specification] standard of 30 minutes of immersion at one meter, and is rated as approved for intrinsically safe operation.”

Intrinsically safe operation, certified in the United States by FM Global, refers to a series of ratings for radios used in a potentially explosive atmosphere, where certain concentrations of gasses or particles in the atmosphere hold the risk of explosion in the presence of a spark.

Frackleton noted that the key differences in the Unity XG 100 from Harris’s other radios are that it operates multi bands (VHF, UHF, 700 MHz, 800 MHz and LMR spectrum), has front keypad programming and includes internal capabilities for Bluetooth, GPS and noise suppression.

“The Unity and our other radios are computer terminals that are fully programmable with full feature sets,” Frackleton said. “It’s up to the user agency to identify a template that’s a subset of functionality for them.”

He noted the noise suppression built into the Unity was in response to firefighter complaints about digital radio voice quality being poor when accompanied by background noise.
“The fireground is a high noise environment,” he pointed out, “with noise sources from pump panels, chainsaws and even PASS alarms. The Unity has two microphones, a classic front-mounted one and a second on the back of the radio for picking up ambient noise.”

Frackleton said that an algorithm in the unit detects the differences in frequency and sound pressure levels on the two microphones and subtracts out the background noise before feeding it to the radio’s vocoder, the device that digitizes an analog voice signal to P25, which then gets transmitted over the air.

Digital Communication

“So now there’s no more switching out of digital to analog because of background noise,” he said, “because now you can hear the digital voice clearly.”

Crisp and clear digital communication is the goal of EF Johnson Technologies, according to Kevin Nolan, the company’s marketing communications director.

“When the Project 25 standard for interoperability was announced, we were among the first to sign up to develop Project 25-compliant equipment,” Nolan noted. “We introduced our ES series of portable handheld radios in 2007 and the ES mobile series in 2008.”

Nolan said all of EF Johnson’s digital radios “ship with the enhanced Project 25 AMBE+2 vocoder, which is the sound engine on a chip inside the radio that produces extremely loud, clear and crisp digital sound.” He said the ES series “has been assessed as the loudest and clearest digital radio because of how well it filters out background noise.”

Compatibility Problems

Project 25 gained momentum when radio system compatibility problems became evident following the Oklahoma City bombing and the Sept. 11, 2001, terrorist attacks. After 9/11, according to Nolan, no federal grants were awarded to any municipality or agency that didn’t purchase interoperable P25-compliant radio equipment.

He said that P25’s phase 2 will center on a modulation scheme, time division and multiple access features. “Essentially,” he said, “they’ll be putting more people on a single frequency.”

Loud Audio

Mike Peterson, engineering director for Motorola, said his firm has been a leader in two-way communications for public safety from the early days of its World War II-era “Handie-Talkie” to the recent launch of the APX 7000 radio.

With the APX 7000, he said Motorola is addressing instant multi-agency interoperability for mission critical first responders.

“The APX radios are multi-band in 700 MHz, 800 MHz and VHF, communicate with current and future FDMA and TDMA networks, and have integrated GPS,” he said. “It’s also a double-sided radio with a data interface, large display and user keypad on one side, while the opposite side has a large speaker that gives 50 percent more audio with noise cancellation capability.”

From a fireground standpoint, he said, “the loud audio when you’re in a high background noise environment is very important.”

The control top of the radio is larger on the APX than previous radios, Peterson said, which resulted in a T-grip at the APX’s top, where a display is located. The top display can be flipped at the push of a button and can be changed at any time, depending on how a firefighter carries the radio.

Both the top and front displays on the radio use intelligent lighting. “If you get an emergency call while you’re on the fireground, the display illuminates in different colors, depending on the call,” Peterson said. “For an emergency, it’s orange/amber. If you lose contact with your control system, the backlight turns red to indicate lost communication. Call alerts will turn green.”

The radio provides for different colors to be programmed into the system. “It’s easier for the user to recognize the condition the radio is alerting them to when there’s color involved.” Peterson said.

He noted that Motorola uses researchers with anthropology and psychology backgrounds to assess the skills and human factors involved with a how a firefighter uses a radio.

Designing Batteries

“Firefighters and police have said that when replacing a battery, they want confirmation it’s seated properly, and many police officers likened it to replacing the ammunition magazine in a gun,” he said. “So now our battery clicks into the bottom of the radio and makes a sound like a cartridge chambering.”

In addition, because firefighters wanted batteries with longer life that would not be bulkier in their hands, he said Motorola extended the length of its batteries, but not their width.

Chris Lyons, director of global product operations for Vertex Standard, said his company offers the industry’s smallest P25 portable radio, in terms of height, thickness and volume.

“Our VX-820 and VX-920 offer a wide range of features in several packages, especially superior protection from dust and water intrusion and an unsurpassed receive audio output,” he said.

Each model offers three versions – one with no display or keypad application, a second with a display and limited keypad and a third with a display and full numeric keypad.

“They all meet the Mil Spec for driving rain and driving water communications,” Lyons said, “and have multi-bands up to 512 channels, plus are available in VHF and UHF.”

The VX-920, he said, is in a slightly larger housing that allows the option of adding a second receiver, has signaling options to do five-tone signaling, and can be ordered in intrinsically safe models.

With P25 digital radios, he said there’s more functionality available, where a great deal of signaling data can be imbedded into the radio’s digital stream, moving data and voice simultaneously.

Biggest Challenge

Steve Nichols, director of homeland security and public safety for Thales Communications Inc., called communications interoperability the biggest challenge with handheld radios.

“Our Liberty multiband land mobile radio covers all the bands,” Nichols said. “It operates in legacy analog, Project 25 conventional and Project 25 digital trunked, as well as offering full encryption.”

In addition, the Liberty has multiband scanning, priority scanning, meets Mil Spec environmental conditions and is submersible to two meters.

Nichols noted that firefighters have requested smaller and lighter radios because of all the gear they carry, but that they still need to be able to operate them while wearing fire gloves.

“We did testing with the Boise Fire Department, and they told us our emergency button was too small and too close to the antenna,” he said. “So we moved the button and made it larger in response to their hands-on testing.”

The Liberty radio also carries a GPS chip in its lapel microphone.

Lyons of Vertex Standard thinks that the future will see more two-way radio products come out with GPS receivers imbedded in them.

“We need some infrastructure to make the location information of GPS useful on the fireground, though,” he said. “In the marine world, you can get marine handhelds with imbedded GPS to display latitude and longitude, but I don’t believe GPS is the solution to fireground position requirements.”

The reason, he said, is that GPS doesn’t work inside of buildings and doesn’t provide the kind of positional accuracy needed by a fireground commander. For instance, it can’t tell the commander which floor a firefighter is on or which side of a wall.

GPS Systems

Lyons said experimental GPS systems in the ultra wide band are being developed by several companies that allow tracking to within a meter and can distinguish between floors. However, he said the systems are in development and would need a special truck, or several of them, depending on the size of the fireground, to operate effectively.

Frackleton of Harris Public Safety and Professional Communications said GPS technology has migrated during the last 10 to 15 years from tactical military applications to public safety, commercial and consumer products.

“GPS can be used to track personnel in outdoor environments like wildland firefighting,” Frackleton said. “The next challenge is tracking personnel inside buildings.”

He suggested radio-frequency identification (RFID) chip technology, used to track products through wholesale and retail distribution channels, might hold an answer for fireground personnel tracking if handheld radios can transmit locations to an incident commander.

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