Examining The Digital Radio Conversion

When’s the last time your cell phone dropped a call?  Or you hit a dead zone?  First responders depend on digital tools, too—switching from analog to digital radios.  Their communication can, often, mean life or death, but with reports of black holes and spotty coverage in the emergency system around Chatham County, is this new equipment helping or hindering those you depend on when you need help?

The change over to digital hasn’t been cheap for Chatham County neighbors.  Local taxpayers alone coughed up 6 and a half million dollars…millions more came from federal grants, and that’s not including what municipalities spent on the radios for their departments.  Is it worth all the money? And can those black holes be fixed?  News 3 asked the questions.

They’re vital in an emergency…and you may not have noticed, but a changeover has been more than a decade in the making.  “The city of Savannah and Chatham County have been working on this since 1996 - is when we put the first part of the network in place - and then in 2005 we upgraded the network to where it would work analog and digital on the same network,” says City of Savannah IT Administrator Bob Davis.  Despite a multimillion dollar price tag… Metro Police Captain Ben Herron says the advantages of digital are what make it worth the expense, “One of the major benefits of moving to digital is where we went from as an agency having maybe 10 channels - I mean it opened up the number to almost limitless.  There are specific channels designated for specific agencies, but then there are common channels that we all have access to, so if there’s an event where you have multiple responders from multiple disciplines - everybody can coordinate.“  And he says the overall sound quality is better, “The audio has a lot more clarity.“

“Analog’s not perfect, and digital’s not perfect - I mean they all have their downfalls and their great things.  The magnificent part about digital is that right up to the very edge of where it can possibly talk to the system - the communication is absolutely crystal clear with zero noise at all,” says Davis.  But it’s those areas on the edge that have led to some complaints. “Initially, we got a lot of complaints in some of the kind of more outlying areas in reference to and even in some areas within the city - this phenomena called digitization - where the audio would come over kind of with some distortion,“ says Capt. Herron.  “The same issues exist with analog radios, it’s just that they manifest themselves differently on a digital radio,” says Davis.

There are also areas of interference due to the bands cellular companies use being too close to bands being used by public safety organizations.  “We have known areas that you drive into and it’s quite honestly a black hole - and it’s this interference from those cellular companies that’s causing the problem,“ says Davis.  The dropout occurs in about 14 known sites around Chatham County - affecting small areas from 250 to 1000 meters around the site.  It’s something Davis says should be corrected soon as work continues to better separate the cellular bands from those used for public safety. 

About 60-percent of the county’s emergency responders - including the Savannah Fire Department - are still using analog.  Davis says that’s a situation that should change over the next few years as the old equipment wears out and is replaced with new digital systems. The transition to all-digital radio is expected to be completed in the next few years.