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Narrowbanding Letter - FAQ
What is Narrowbanding?
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 (LMR) systems to migrate to at least 12.5 kHz efficiency technology by January 1, 2013. More specifically, all existing Part 90 radio systems operating in the 150-174 MHz and 421-470 MHz bands have until Janurary 1, 2013 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. 

What is the purpose of Narrowbanding?
Currently, the majority of UHF and VHF LMR licensees operate using 25 kHz efficiency technology; however, the UHF and VHF frequency bands are congested with limited spectrum available for system expansion or implementation of new systems. The migration to at least 12.5 kHz efficiency technology will require licensees to operate more efficiently, either on narrower channel bandwidths or increased voice paths on existing channels. This will allow the creation of additional channels within the same spectrum, thereby supporting more users. 

What frequency bands are subject to the Narrowbanding mandate? 
The 150 - 174 MHz and 421 - 470 MHz bands are subject to the Narrowbanding mandate. 

What is the deadline to modify? 
After January 1, 2013, all licensees must operate in at least 12.5 kHz efficiency. Additionally, after January 1, 2013, the Commission no longer allows manufacturing or importation of equipment that includes a 25 kHz mode. 

What will happen if I fail to comply with the FCC Narowbanding mandate? Can I continue to operate at 25 kHz efficiency on a secondary status after January 1, 2013?
No. Licensees are prohibited from operating 25 kHz efficiency equipment after January 1, 2013. Non-compliance will be considered a violation that could lead to FCC enforcement action. View the following link for details. 

FCC ENFORCEMENT ADVISORY    (August 22, 2012)

"The Enforcement Bureau is committed to aggressively enforcing the narrowbanding transition deadline and violators may be subject to enforcement action. Penalties for non-compliance may include license revocation, and/or monetary forfeitures of up to $16,000 for each such violation or each day of a continuing violation, and up to $112,500 for any single act or failure to act.7"  

If I need to Narrowband, do I need to implement digital technology?
​No. Licensees can operate in either analog or digital formats as long as they 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 channel. Licensees stay on the same channel center(s) but reduce the bandwidth of the channel(s) currently used, from 25 kHz to at least 12.5 kHz and change the emission designator on the license. Alternatively, licensees may stay on the same 25 kHz channel but implement at least 12.5 kHz equivalent technology on that channel. 

If I currently have a license for a 25 kHz channel, will I automatically be entitled to license two 12.5 kHz channels after I Narrowband?
No. Your 12.5 kHz channel will remain on the same 25 kHz channel center. Your current 25 kHz channel will not be split into two 12.5 kHz channels. You will need to justify and apply for additional 12.5 kHz channels through a certified frequency coordinator. 

Will I lose coverage area when I Narrowband? 
It has been estimated that Narrowband compliance can result in a 3 dB loss in signal strength; however, this rule of thumb is based upon a "plain vanilla" Narrowbanding scenario where a 25 kHz analog system converts to a 12.5 kHz analog system. Consult with a manufacturer and/or consulting engineer for a better estimate of how Narrowbanding will affect your particular system. 

Has the FCC established a schedule for mandatory migration to 6.25 kHz efficiency?
No. The Commission has not set any date by which licensees must operate in 6.25 kHz efficiency. The current mandate only requires users to migrate to at least 12.5 kHz efficiency by January 1, 2013.


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