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FCC Narrowbanding Compliance

FCC Narrowbanding Compliance

FCC logo Frequently Asked Questions

What is Narrowbanding?

In an effort to promote more efficient use of spectrum, the FCC mandated all VHF and UHF Public Safety and Industrial /Business licensees using 25 kHz land mobile radio (LMR) systems migrate to narrowband 12.5 kHz efficiency technology by January 1, 2013.

What is spectrum efficiency?

Currently the UHF and VHF frequency bands are congested and often there is not enough spectrum available for licensees to expand their existing systems or implement new systems. This mandate requires licensees to operate more efficiently, either on narrower channel bandwidths or increased voice paths on existing channels. This will allow creation of additional channels within the same spectrum, thereby supporting more users.

What does Equivalent Efficiency mean?

The FCC does not mandate channel width, it mandates spectrum efficiency. FCC rules require 12.5 kHz or equivalent efficiency. Any of the following meet the 12.5 kHz equivalent efficiency requirement:

  • One voice path in a 12.5 kHz channel
  • Two voice paths in a 25 kHz channel
  • 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

Does Narrowbanding require me to implement digital equipment?

No. Licensees can operate in either analog or digital formats as long as you operate at 12.5 kHz efficiency.

Does Narrowbanding require me to change frequencies or obtain new channels?

No. Narrowbanding does not require moving to another frequency band or different channels. Licensees stay on the same channel center(s), but reduce the bandwidth of the channel(s) currently used, from 25 kHz to 12.5 kHz and change the emission designator on the license. Alternatively, licensees stay on the same 25 kHz channel but implement a 12.5 kHz equivalent technology on that channel.

Will I receive two 12.5 kHz channels when I change from my currently licensed 25 kHz channel?

No. As noted above, you remain on the same 25 kHz channel center, not splitting the channel into two 25 kHz channels. If you need additional capacity, you will need to apply for additional 12.5 kHz channels to the FCC through your frequency coordinator.

What will happen if I fail to comply with the FCC Narrowbanding mandate? Can I continue to operate at 25 kHz efficiency on a secondary status after January 1, 2013?

No. The FCC will prohibit licensees from operating 25 kHz efficiency equipment on a secondary basis. Non-compliance will be considered a violation subject to FCC Enforcement Bureau action, which may include admonishment, monetary fines and loss of license.

How can I tell if my radio equipment is 12.5 kHz capable?

All radio equipment certified by the FCC since February 14, 1997 is 12.5 kHz efficiency capable. If you are unsure if your equipment falls under this mandate, call your local two-way radio dealer and ask them  to assist you in this matter.

How do I upgrade my existing 12.5 kHz capable equipment?

In most cases, the Programming Software can be used to reprogram the subscriber and base station radios to operate at 12.5 kHz. Typically, infrastructure site equipment (duplexers, multicoupler, window filter) does not require any changes. Contact your radio local two way radio dealer if you need assistance or call us here at Skye Rentals

Has the FCC established a schedule for mandatory migration to 6.25 kHz efficiency?

No. 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 by January 1. 2013. Based on the 12.5 kHz migration time line, we believe that any potential future FCC decision to require users to migrate to 6.25 kHz efficiency will take a considerable number of years.

- Rick Gamboa


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