Augusta, we have a problem
The mighty oak tree springs forth from the tiny acorn. Where public-safety land-mobile radio systems are concerned, the acorn takes many forms. For the state of Maine and its statewide radio system that’s currently being deployed, the acorn was interference to state police communications in the southern portion of the state caused by a system in neighboring New Hampshire more than a decade ago.
At the time, Ray Bessette was a sergeant with the Maine State Police and newly appointed as the agency’s communications officer. He was assigned the task of figuring out what to do about New Hampshire’s new digital narrowband system, which not only was wreaking havoc in Maine — where the state police was on an analog wideband VHF system — but also in portions of Rhode Island and New York State. According to Bessette, New Hampshire tried to mitigate the interference by deploying directional antennas and adjusting power output but to no avail.
“The interference was so annoying that we had troopers punching the frequency out of their scan bank — this was the primary frequency for all of southern Maine — and calling the barracks from their cell phones,” Bessette said. “So, I had a pretty bad situation that I needed to fix.”
His first instinct was to contact the FCC, because the commission’s rules prohibit one licensee from interfering with the operations of another licensee. That seemed simple enough. But when it comes to dealing with the FCC, nothing ever is simple, as Bessette quickly learned.
“I really got educated quickly as to regulatory priority,” Bessette said. “Basically, New Hampshire was putting in a system that was more efficient and heading in the direction that the FCC wanted. The commission basically said to the state of Maine, ‘You fix it.'”
That soon led Bessette to his second harsh lesson — there was no easy fix to this problem. Bessette first tried adding PL tones in an attempt to filter out the noise. “But the guys could still see it lighting up their radios and in their minds, if they weren’t able to reach a dispatch center, it was because of the interference, even if they couldn’t hear it,” he said.
Bessette then considered moving the state police system to another frequency, but no open airwaves were available. “What a rude awakening that was,” he said.
The situation seemed hopeless. But then Bessette, who now is a major with the state police, experienced an epiphany.
“I was getting pretty frustrated, but then one night, I said to myself, ‘My gosh, the state aircraft frequency,'” he said. “It was a simplex frequency, but it obviously was licensed for statewide use. I figured that if we had been interfering with anybody, we already would have heard about it. So we stole a frequency from our state aircraft and changed over thousands of end-user radios, tower sites and communications consoles in southern Maine.”
That was one big problem solved, but others were looming. The New Hampshire dilemma, which occurred in 1998, first put narrowbanding on Bessette’s radar screen. But when the FCC issued its order that all LMR systems operating below 512 MHz must use 12.5 kHz-wide channels or equivalent by Jan. 1, 2013 — from the previous 25 kHz-wide channels — to improve spectral efficiency, Bessette was forced to take a hard look at the state police’s legacy system, which had been constructed in 1974. He didn’t like what he saw. “Legacy is just a nice term for antique,” Bessette said.
The system had numerous coverage gaps — thousands of square miles in some cases — and would routinely fail. The latter was particularly problematic, because many of the 76 towers that comprised the system had only one radio, so redundancy was a major issue. Also, replacement parts were difficult to find, which resulted in significant downtime — a huge issue for troopers in the field.
The tipping point occurred after Bessette hired a consultant to conduct a user-needs analysis. Part of the process involved monitoring channel utilization. What they found was startling, Bessette said.
“Through the normal course of actions … we were maxing out past 100% several times throughout the day on some of our primary frequencies,” Bessette said. “At times, troopers were pulling into their driveways, and they wanted to let the barracks know that they were off-duty and at home, and they would sit there with the microphone in their hands waiting for a break — and they eventually would give up, go inside the house and call on the phone.
“I knew I had a problem.”
- Read our next story, “Gestalt principle on display in Maine,” for more on this story, including how disparate networks coalesce to create a statewide system that is far more robust, reliable and secure.
