If it’s not broken, why fix it?
March 1, 2011
During the past decade, operators of land-mobile radio (LMR) networks have faced two major changes to their systems mandated by the FCC: reconfiguration of the 800 MHz band and narrowbanding of the UHF and VHF frequencies. Both initiatives have proved to be significant undertakings, with rebanding likely taking at least a decade and many LMR operators expressing concern that they will not be able to meet the FCC’s Jan. 1, 2013, deadline for narrowbanding, despite having 15 years’ notice of the requirement.
But a potentially even greater challenge awaits LMR operators intent on maintaining intrinsically safe (IS) radio systems, because the new standard — set to become effective on Jan. 1, 2012, a year before the narrowbanding deadline — for handheld devices promises to force changes to IS handsets that most engineers believe can be met only by reducing the power levels of portable radios significantly. Instead of transmitting at 3 to 6 watts as LMR radios do today in the U.S., the new IS radios likely will support power outputs of 0.5 to 2 watts, according to multiple industry sources.
For LMR operators in the U.S., this is problematic. Not only would the change mean replacing portable radios that may have been purchased recently to satisfy rebanding or narrowbanding requirements — at a time when money is scarce for enterprises and public-safety agencies — but it also would mean redesigning entire LMR systems with additional base-station sites to maintain the same portable coverage for IS radios that is enjoyed today.
These realities translate to considerable added expense to existing LMR systems, as a model from Pinellas County, Fla., indicates. But even these kinds of projections reflect only the basic costs, because securing additional sites for an LMR network can be extremely difficult, said Fred Moloznik, senior director of product safety and regulatory compliance for Motorola Solutions.
“You can’t go out and say, ‘I think I’m going to add five sites,’ and just do it,” Moloznik said. “There are spectrum considerations and frequency-coordination considerations, so that’s another concern customers have.”
Furthermore, many firefighters and oil-refinery personnel rely regularly on direct radio-to-radio communications, so as not to be dependent on a network. The expected reduction in transmission power for new IS radios would mean reduced range in such instances and would make in-building communications much more challenging, according to several industry sources.
Given these negative impacts and the fact that there has been no indication that current intrinsically safe LMR radios have created any safety issues, many question whether a new IS standard is needed.
“I hate to use a cliché, but it seems to be a solution in search of a problem,” said Doug Aiken, chief of Lakes Region Mutual Fire Aid in New Hampshire. “Nobody I’ve talked to understands why we need to make these changes.
“It’s just very frustrating. If it’s not broken, why are we fixing it? I don’t understand what the rush is to harmonize [IS standards] with Europe.”
Most LMR operators only learned of the impact of the proposed intrinsic-safety standards last summer, giving them less than 18 months to comply, while they were given several years’ notice to meet rebanding and narrowbanding mandates. With this in mind — as well as the fact that no LMR products are available in the U.S. for purchase that meet the new IS standard — they want implementation of the IS standard delayed or waived completely.
Meanwhile, officials for FM Approvals and Underwriters Laboratories (UL) note that manufacturers have known since 2006 that the intrinsic-safety standard was being changed but opted to ignore it and not notify their customers. In fact, they say that the IS standard was supposed to become effective on Jan. 1, 2010, but a two-year extension was granted, resulting in the current 2012 implementation date.
Caught in the middle of the debate between the manufacturers and the standards bodies are LMR network directors, who find themselves in the unpleasant predicament of having to tell their company or government employer that the recent time and money investments in rebanding or narrowbanding may have to be redone to meet the new IS standards.
“People have put their jobs on the line with a lot of money at stake, and you have this [intrinsic-safety standard] that’s totally irrational,” said Greg Kunkle, a partner in the Washington, D.C., law firm of Keller and Heckman. “They’re between a rock and a hard place on this one.”
Tangled web of standards
At the heart of the controversy is intrinsic safety, a time-honored standard certified by UL and FM Approvals that is designed to ensure that electronic equipment can operate in hazardous atmospheric environments — for instance, a monitoring device in a gas tank — without risk of explosion. In the latest intrinsic-safety standard, a key goal of UL and FM Approvals officials is to harmonize the traditionally separate North American standard — last approved in 1988 — with the standard used throughout the rest of the world.
“Motorola believes that the new intrinsic-safety standard is really not appropriate for a land-mobile radio product,” Moloznik said. “We understand why you would want a global standard, but we think there should be an option that if you just want to have a North American standard, you can have that, too — as long as there’s no safety issues with it.”
The IS standard does not mention transmission power levels limits for portable radios, but it does reference a standard set by the International Society of Automation (ISA) that mandates changes in radio design — already implemented in European LMR technologies such as TETRA — that effectively would require power outputs from portable radios to be reduced, if the current LMR portable form factors are maintained, according to most industry sources.
Vendors such as Motorola and Harris sell TETRA equipment in other parts of the world, but the equipment is not certified in the United States. Even if the TETRA certification issues could be addressed in a timely manner, U.S. LMR operators would have to revamp their system designs to maintain their current portable-radio coverage while using TETRA radios, which typically transmit at 1 or 2 watts, Moloznik said.
“It isn’t just a simple matter of, ‘What product can you sell me?’” he said. “It goes back to the whole system-coverage issue. Am I going to buy a product that has less power if I don’t — at the same time — figure out system coverage?
“I don’t think most of the customers are going to sit back and say, ‘OK, now I’m going to start buying this 1- or 2-watt radio. They’re going to say, ‘Before I make that decision, what are my system-coverage considerations here? So there’s a lot of planning that has to go on before everybody’s ready to buy one of these radios.’”
At Harris, engineers are trying to design portable radios that meet the new IS specifications but operate at the power levels traditionally used for LMR in the United States, so that existing LMR system designs and infrastructure can be maintained to provide similar coverage, said Don Martz, director of engineering at Harris. However, the physics involved in meeting the new IS standard specifications will require the proposed portable radio design to be noticeably larger, he said.
“The design concepts that we’ve run by [FM Approvals] may allow us to meet current power levels,” Martz said. “It’s not a sure thing by any means and there are some challenges, but that is our goal — to try to meet the current power levels. If it’s going to make the radio … too much larger, it’s going to make it impractical, so we may have to go back to rebalance those design trade-offs.”
Even if the Harris design for a new IS radio is blessed by FM Approvals and customers from a functionality standpoint, cost still would still loom as an issue for many, if not most, LMR operators. Currently, vendors are able to use many of the same components in both IS and non-IS radios, allowing them to leverage economies of scale to secure better pricing. If IS radios are redesigned to meet the new standard, many of the parts promise to be unique to the IS radios that are sold to a relatively small market.