Digital-to-analog interference may be an opportunity for dealers

Digital-to-analog interference also could occur if frequency coordinators pack adjacent-channel licensees too closely together.

“That’s a potentially serious problem,” Jacobsmeyer said.

There are a few remedies that users can consider, with the help of their dealers. One would be to identify the culprit and then determine the root cause of the interference. If the interferer is operating at transmit power that is too high, the licensee might be convinced to dial it down. If the interferer is operating without a license, the culprit might not even be aware that one is needed. If the operator applies for a license, the system would be subject to frequency coordination.

“Most people want to be good neighbors, and LMR is like a neighborhood,” Guller said.

But doing that due diligence can be a costly, time-consuming and mind-numbing process that involves drive testing and combing through the FCC’s voluminous licensing database; it’s a process made more complicated, if the offending entity has multiple licenses.

“In one case, the system that was causing the interference was 45 miles away,” said Steve Keller. “We never would have guessed that they would be the culprit.”

Dave Keller said the ideal solution would be for the FCC to start designating certain channels as analog-only.

But there is no chance of that happening, according to Alan Tilles, chair of the telecommunications practice at Shulman Rogers and a longtime contributor to IWCE’s Urgent Communications.

“Number one, they’re not making more spectrum,” Tilles said. “That means you’re taking existing spectrum and saying to those on that frequency, that from now on it’s going to be analog only. So you’ve taken somebody’s spectrum and totally devalued it. How many years are we going to be fighting at the FCC over the fact that we’ve just devalued this guy’s spectrum? Does the commission have the ability to do this? Yes. But they’ll never tackle it.”

Guller has a far simpler solution that could provide a very lucrative opportunity for two-way radio dealers in areas where this problem exists: convince analog customers to upgrade to digital technology.

“You should be selling more digital radios, and your customers should be buying them,” Guller said. “If you’re operating an analog system and sharing channels, you’re going to experience digital interference.”

Dave Keller agreed.

 “There are going to be more and more digital systems out there, so analog quality is going to go down over time,” he said.