Narrowband? What's narrowband? So what?
PowerPoint (right click to Save As....) from Illinois Association of Fire Districts June 24, 2004
Narrowband, what is it?
Background: All two-way radios
use a radio channel that has a particular size, called bandwidth. In the past, all radio channels
were 25 kHz wide. Any older radio, designed to work on a 25 kHz channel, will
now be referred to as "wideband".
As far back as 1992, FCC began a process known as "refarming". One of the goals of refarming was to create more radio channels to meet the needs of two-way radio users. In short, the FCC decided to create "new" radio channels that were one half the size of the older ones. Changing the channel size effectively makes twice as many radio channels. So, the new two-way radio channels will now be 12.5 kHz in size and known as "narrowband".
Quite often, in an effort to explain refarming in layman's terms, it was stated that "It's like taking a four-lane superhighway and narrowing each lane to get eight lanes total." This sounds good - doubling the available lanes, or in this case, radio channels. Except that if you fail to also narrow the cars and trucks, the vehicles will be sideswiping each other, or at the very least, smacking mirrors - a layman's explanation of "interference"! If some vehicles are narrow, and some wide, the highway will be chaotic - just as the radio interference will be chaotic if the change is not coordinated.
As the process of "refarming" moved along, the FCC created
mandates for the two-way radio equipment manufacturers. In 1997, all new two-way
radio models had to be capable of operation on the "new 12.5 kHz narrowband"
channels. This is often called "dual-mode" equipment since the radio can
accommodate both narrow- and wide-band channels. The idea was to begin to move gently toward narrowband channel
operation over time. At that time, the FCC did not create any mandates to remove
older wideband radio units from service or require you to use a new narrowband
channel.
FCC Actions, narrowband mandates:
On February 25, 2003 the FCC released updated "narrowband"
mandates. These actions are designed to phase in narrowband (12.5 kHz) and phase
out older wideband (25 kHz) channels over the next 10 years. The process
consists of 4 main mandates. A final set of rules were posted in the Federal
Register on July 17th, 2003. FCC
Rule in PDF format.
Mandate 1)
All existing wideband (older) radios may
continue to operate until January 1, 2013. Public Safety has until January 1,
2018. After that date, two-way radios must operate completely on the new
"narrowband" (12.5 kHz) channels.
Mandate 2)
Two-way radio manufacturers cannot
manufacture, import or sell any models of wideband (25 kHz) equipment after
January 1, 2008.
Mandate 3)
Manufacturers who submit any new two-way
radio models for FCC certification after January 1, 2005 may not offer new
radios that contain the ability to operate on older wideband (25 kHz)
channels. This means no more "dual-mode" radios - they will ONLY work in
narrow-band mode and NOT be compatible with existing wide-band systems.
Mandate 4)
After January 17, 2004, FCC license
applications for new radio systems will not be accepted for older wideband (25
kHz) channels. This portion of the Rule, despite the Petitions for
Reconsideration, HAS BEEN
STAYED as of December 3, 2003. In addition, limitations will be placed upon modifications
(changes) to any existing wideband FCC licenses. This may be up to
interpretation by a frequency coordinator, but any new system, or an existing
system that expands it's service area or relocates a base station may be
required to move the entire system to narrowband - a costly proposition.
Summary of the Mandates
Starting January 17, 2004, you may not license any new two-way
radio systems in the older wideband mode. You will be limited in making any
changes to your existing wideband license. In fact, the coordinators will likely
ask that applications be submitted October-November of 2003 is order to process
the license. After 2005, the radio manufacturers
must begin to eliminate older wideband mode from any new models of two-way
radio. After 2008, you will not be able to purchase any new two-way radio
equipment that will operate in the wideband mode. In 2018 you will have to take all older wideband equipment out of service.
How this affects you:
For now, all older two-way radio systems will continue to operate
as they have in the past. Short term, do not let your existing FCC license
expire under any circumstances. If you should receive anything in the
mail concerning your FCC license, contact
IMSA or APCO
immediately for assistance. You may also contact a co-chairmen of the
MABAS Radio Communications Committee listed on the bottom of the
home page. You do not want to lose your current wideband
license.
Over the next year, it would seem prudent to evaluate how many older wideband two-way radio units you have in service. These older units will need to be phased out over time. Some of your newest two-way radios are likely to be "narrowband ready" right now because they are "dual-mode".
Over the next 5 years, updating your older two-way radio units, a few at a time, will put you in the best position to be "narrowband" ready for the future.