P-25 fireground testing delayed, departments still plagued with problems

Urgent Communications reports that the Public Safety Communications Research (PSCR) Project 25 fireground testing scheduled for this month has been delayed until this spring. The delay was forced by an extended comment period.

Two years ago, that same laboratory found that digital radios fared far worse than their analog radios on the fireground. The likely problem? Ambient noise — most notably SCBA masks, SCBA alert bells, PASS communicators, water pumps, and other ambient noises associated with working fires. The ambient noise distorts the audio, because the IMBE vocoder is generally designed to capture human voice and cut the background noise out. But when you have dozens of other competing sounds that are as loud or even louder than the human voice, the vocoder can become confused and the audio is distorted.

These radios, which were designed to help firefighters, are often blamed as a contributing cause of some firefighter injuries and even deaths when mayday calls were not heard by others on the Cincinnati-area digital radio systems. Other complaints include dead spots, an inability to override ongoing radio traffic with more urgent radio traffic (getting a busy signal instead), and a one- to two-second delay for transmitting after squeezing the push-to-talk button.

Fire departments aren’t the only agencies grappling with issues. Police departments are also suffering from dead spots in coverage that cropped up only after the digital systems were deployed.

In Philadelphia, their new Motorola radio system suffered over a dozen complete radio system failures in three years, even putting the police commissioner’s safety in jeopardy once when breaking up a street disturbance.

Similar failures are being reported all across the United States, not only with Motorola P-25 systems but M/A-Com OpenSky systems as well. In some instances, departments are bailing on their multi-million dollar digital radio systems in favor of their older analog systems.