10/29/11 — County's new radio system facing interference issues

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County's new radio system facing interference issues

By Steve Herring
Published in News on October 29, 2011 11:28 PM

Older and stronger analog radio systems from other communities are causing problems for Wayne County's new digital communications system, officials say.

County officials say the trouble is not widespread, but that it does pose the potential for disrupting communications during an emergency.

And they say they have installed software that should ferret out problem areas -- whether they are local individual radios or radio systems in other communities using a similar frequency that overpowers and drowns out the newer, lower-powered digital ones being used by the county.

Officials think some of the local interference is incidental, caused by individual radios whose frequencies are similar to the ones being used by the county. While there is no solid evidence, it has been speculated that some of the problem could be caused by people who are improperly using the old radios that were eliminated by the new system.

The price tag for the $10 million system included new radios for all of the county's fire departments, law enforcement offices and rescue units.

"We knew, at the onset, there would be the possibility of some interference," Wayne County Emergency Services Director Joe Gurley said. "There is more interference at this point in time than I think the studies actually said. Certain places like Appomattox, Va., which is up in the northwest corner, mountainous area. They probably have a very tall tower that is pushing a lot of wattage. We are getting a lot of inference from there.

"We are getting a lot of interference from Orange County. There is a place in Myrtle Beach (S.C.). From that point on, it is kind of hit and miss. But then, we are getting some localized interference that we are trying to identify and see if it is a mishap of frequencies that were misplaced or placed in the wrong category. We are trying to record some of that to see what the localized interference is."

Once Appomattox goes to the federally mandated narrow-band digital, as Wayne County has, it will lose one-third to one-half of its (broadcasting) power, Gurley said.

"Which means they won't get out as far," he said.

The fact is that digital signals are not really weaker than analog signals, the officials said. Rather, the FCC has mandated that the power wattage be limited to 50 watts per transmit station. That is the reason for the county's five tower sites instead of the one required for the analog system.

Basically, the officials say, the county is transmitting a more precise or focused signal a shorter distance to much more sensitive receivers or radios. However, the analog systems that are still allowed to broadcast at a higher power can still override the digital one.

One comparison would be the difference in hunting a rabbit with a shotgun versus a rifle. The shotgun covers more area and is more forgiving of the aim and might get the job done. The rifle requires skill and precision, but will always get the job done.

An analog signal gradually diminishes the farther it travels from its source until the transmission fades away, while the digital signal reaches a point and abruptly vanishes.

Another way to view the interference is to think of two commercial radio stations whose frequencies are close together. A person might be listening to nearby Station A only to have Station B, which is farther away but broadcasting with more power, overpower the closer station.

It has been three years since the county decided to replace its 40-year-old hodge-podge analog system with a digital one to comply with the FCC mandate that emergency services "narrow band" their communications frequencies by Jan. 1, 2013.

Only one person spoke three years ago during a public hearing before county commissioners approved the system. He said the county needed tax relief and not a new radio system.

Local fire chiefs at that time said the county was in dire need of a system to replace the old one since communications were not good in outlying sections of the county. Those same people called the system the county settled on "the best system for the county."

The county rejected efforts by some to sign on with the state-owned VIPER radio system saying the county needed to own and control its own system.

The system is designed as 95/95 meaning it provides coverage in 95 percent of the county, 95 percent of the time -- even with portable radios.

There have been grumblings since the approval and particularly since the switch over to the new system began several months ago that it is not delivering on its promises.

Gurley has said the system is not yet performing as it should, but that it will take time to get it to where it should be. That includes cleaning up the interference created by systems like the one in Appomattox, Va.

One option the county will consider is lowering its communications antenna receivers so they won't receive as much of the outside signals. But lowering the receivers could reduce the ability to receive signals from local portable units and would require that additional receivers be installed to better capture them, he said.