Narrowbanding – in the homestretch
Ready or not, the Federal Communication Commission’s effort to make more efficient use of the VHF and UHF radio and television spectrum frequencies goes into effect in less than a year. Under the looming requirement, all non-federal public safety and private entities using larger, 25 Hz bandwidths make the change by Jan. 1, 2013.
It has been almost 20 years since the U.S. government first began planning for a switch, according to David Firth, associate deputy of FCC’s public safety and homeland security bureau. At that point in time the number of available channels had already begun to dwindle, and leaders were confident technology would continue improving to a point where a narrowband platform would be feasible.
In 2004 a drop-dead date of Jan. 1, 2013, was set for the switch. Licensees were given seven years to purchase equipment that would accommodate 12.5 kHz technology.
Narrowbanding is an effort to ensure more efficient use of the VHF and UHF spectrum by requiring all VHF and UHF public safety and industrial/business land mobile radio systems to migrate to at least 12.5 kHz efficiency technology. Meeting the Jan. 1, 2013, deadline means FCC licensees must meet a 12.5 kHz equivalent efficiency requirement, specifically one voice path in a 12.5 kHz channel, two voice paths in a 25 kHz channel and data rates of 4.8 kbps per 6.25 kHz channel, such as 9.6 kbps per 12.5 kHz and 19.2 kbps per 25 kHz channel.
More specifically, all existing Part 90 radio systems operating in the 150-174 MHz and 421-512 MHz bands have until the date to convert those systems either to a maximum bandwidth of 12.5 kHz or to a technology that provides at least one voice path per 12.5 kHz of bandwidth or equivalent efficiency.
Probably half of the users in the FCC’s licensee database have already complied with the regulation, Firth said. In April, 32,000 letters went out to U.S. licensees who had not yet notified the FCC they had fully narrowbanded. Licensees need to modify their license with the FCC when the change is complete.
Failure to comply with the regulation will make a licensee eligible for enforcement consequences. Firth said the bureau could investigate and impose sanctions or fines. Additionally, users may find they have inoperability issues after Jan. 1, 2013, due to interference by those who did convert. Stragglers may also encounter interface issues with narrowband equipment.
Licensees who feel they have a legitimate reason for not completing the switch will be required to seek a temporary waiver and prove extenuating circumstances beyond what most users had to deal with. Firth said the excuse had better be good.
“We know that this isn’t something anyone can do overnight, but that’s why we gave them seven years – more, really, since we started warning everyone about the direction we were headed.”
The FCC supposes in many cases, municipal departments are aware of the deadline and are working to meet it. Their town councils, mayors, etc., may not be, though, so the department contacted state governors at the beginning of 2011 to make sure their agencies and municipalities were implementing the change.
The FCC stopped selling licenses that include wideband channels Jan. 1, 2011. During a grace period, equipment capable of transmitting on either wide or narrowband could be sold to accommodate businesses or municipal departments who needed to implement the change slowly. As of the official switch date, the sale of any wideband-capable equipment will be prohibited across the nation.
In December, Firth said licensees should not notice a difference in the quality of voice transmissions on handheld radios.
“Users should notice nothing, but you’ll need a radio that will do it – that can get useable voice channels on half the bandwidth,” Firth said. “It’s not a question of clarity, because there’s enough data in the signal so it can be understood.”
The FCC has not set any date by which licensees must operate in 6.25 kHz efficiency. The current mandate only requires users to migrate to 12.5 kHz efficiency. Based on the 12.5 kHz migration time line, the agency has said, any future decision to require users to migrate to 6.25 kHz efficiency will take a considerable number of years to implement.
By Jodi Magallanes
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