Jan 26, 2012 6:52 PM, By Glenn Bischoff (glenn.bischoff@penton.com)

The FCC’s recent decision to permit the use of two 6.25 kHz channels utilizing the NXDN 4 kHz emission mask within a single 12.5 kHz channel not only offers greater spectrum efficiency to licensees operating trunked systems in the UHF band (from 450 MHz to 470 MHz), it also greatly simplifies the narrowbanding process, according to Ralph Haller, chairman of the National Public Safety Telecommunications Council.

“It allows someone, without doing additional work other than changing the emission designator on their license, to get two channels where they previously had one,” Haller said. “It’s an easy way to convert a single channel into two without having to do much engineering.”

According to Mark Crosby, president and CEO of the Enterprise Wireless Alliance, the ruling only applies to exclusive-use channels, which are “like diamonds,” highly coveted by trunked system operators because they don’t have to be monitored. In contrast, a control channel that is shared always must monitor to determine whether another licensee is using the channel, or interference will occur. The result is a certain measure of unwanted latency. Such shared channels represent at least 85% of the channels utilized between 450 MHz and 470 MHz, Crosby said.

“Most people want them for their control frequencies, and people who invest in those technologies, their systems hum, and it really supports the investment in that trunk system,” Crosby said. “So, exclusive-use channels are very important for any public-safety or business-and-industrial entity investing in digital trunked systems.”

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© 2012 Penton Media, Inc.