Hytera-Cobb TETRA collaboration might be the start of something big
“We were going to be spending a lot of money, so it was important that we got the most bang for the buck,” said Jay Kenyon, a Cobb vice president.
Last September, the FCC sanctioned the use of Terrestrial Trunked Radio (TETRA) technology in the U.S. The action was the culmination of a long lobbying battle to bring the popular technology that is being used worldwide—predominantly in Europe—to the U.S. to provide a digital radio option that was less expensive than Project 25, but more feature-rich and hardened than Digital Mobile Radio (DMR) technology. But, in the ensuing months, TETRA’s arrival has been more about promise than actual deployments, though some experts believe that significant activity has been bubbling beneath the surface.
A couple of weeks ago, Cobb EMC—an electrical cooperative that serves metropolitan Atlanta and southeast Georgia—announced what is believed to be the first TETRA deployment in the United States. Previously, PowerTrunk conducted TETRA trials with New Jersey Transit and MTA New York City Transit, but no deployments have been announced as yet.
Cobb’s four-site system will be installed by Norcross, Ga.-based two-way radio dealer Radio One and will leverage infrastructure and subscriber gear manufactured by Hytera. Testing is expected to begin by Thanksgiving, and the system is scheduled to be operational by the first of 2014.
At the beginning, all Cobb officials knew was that their existing digital radio system had reached the end of its life—they had no preconceived notions as to what would replace it. Their vendor had suggested an upgrade to the latest version of the existing technology, but the utility’s officials suspected that there were a lot more options to consider. To ensure a thorough vetting of the myriad options, Cobb hired a consultant.
“We were going to be spending a lot of money, so it was important that we got the most bang for the buck,” said Jay Kenyon, a Cobb vice president. “Our consultant didn’t tell us what to buy but instead gave us all of the options.”
That was accomplished by conducting an open-house event, where representatives of 12 companies made their pitches, not just to Cobb executives, but also to stakeholders—a wrinkle that impressed Gary Lorenz, Hytera’s vice president of sales and marketing.
“They brought in the people in the bucket trucks, the ones who are out in horrible storms trying to restore power,” Lorenz said. “I was struck by that. The whole process was very thorough—they wanted to get this exactly right.”
The choice came down to Hytera’s TETRA system and another vendor’s DMR system. Though the TETRA system was more expensive, it had a few significant advantages. One is that it will cover Cobb’s 400 square-mile footprint with just four sites, compared with the seven sites that the DMR system would have required, resulting in significantly reduced infrastructure costs. Another is that TETRA gear is public-safety rugged, an important consideration given the harsh conditions in which utility workers often find themselves.
But the tipping point was that TETRA is based on four-slot TDMA, while DMR is based on two-slot TDMA.
“With TETRA, we could have one control channel and three talk paths,” Kenyon said. “So we had full-duplex capability. In contrast, DMR [requires] two control channels, so if we had a full-duplex conversation on a four-channel site, there wouldn’t be any channels left for any standard radio communications.”
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Source: Urgentcomm
