Private land mobile radio (LMR) systems - including municipal government and State and local public safety systems - use blocks of radio spectrum called channels. Historically, LMR systems have used 25 kHz-wide channels. In December 2004, the Federal Communications Commission mandated that all private LMR users operating below 512 MHz move to 12.5 kHz narrowband voice channels and highly efficient data channel operations by January 1, 2013. This migration complements a National Telecommunications and Information Administration mandate for more rapid Federal agency migration to 12.5 kHz narrowband operation by January 1, 2008. The earlier Federal deadline affects State and local FCC licensees that interface or share frequencies with Federal radio systems. Using narrowband channels will ensure that agencies take advantage of more efficient technology and, by reducing channel width, will allow additional channels to exist within the same spectrum space


Are your radio system and subscribers ready for Narrowbanding?

The Federal Communications Commission (FCC) has mandated all public safety and industrial/business licensees convert existing 25 kHz radio systems to minimum narrowband 12.5 kHz efficiency technology by January 1, 2013. The purpose of the narrowband mandate is to promote more efficient use of the VHF and UHF land mobile frequency bands.

Who is affected?

All land mobile Part 90, 25 kHz efficiency systems operating on VHF (150-174 MHz) and UHF (421-512 MHz) frequency bands.


The FCC has set the following deadlines for licensees and manufacturers, requiring migration to minimum 12.5 kHz efficiency systems.


January 1, 2011 Applications for new licenses or for license modifications to expand existing service areas must specify at least 12.5 kHz efficiency. The FCC will no longer accept applications for systems operating at 25 kHz efficiency.

January 1, 2013 All licensees must convert to and operate in at least 12.5 kHz efficiency. Existing dual mode (25/12.5 kHz) equipment must have the 25 kHz efficiency mode disabled via software. Equipment capable of operating only at 25 kHz efficiency must be replaced.

Note: The FCC has NOT set any date by which licensees must operate in 6.25 kHz efficiency in these bands.


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

What do I need to do before January 1, 2011 versus January 1, 2013?
After January 1, 2011, users who apply for a new license or modify their existing license must specify 12.5 kHz efficiency. If you need to expand your service area for your existing 25 kHz efficiency system, you will need to submit an application before January 1, 2011. Manufactures can no longer certify equipment capable of operating at 25 kHz efficiency after January 1, 2011. However, per the FCC Order, released June 30, 2010, manufacturers can now manufacture, import, and market equipment capable of operating at 25 kHz efficiency until January 1, 2013. This will allow you to purchase additional or replacement radios until you migrate to 12.5 kHz efficiency by that date, as mandated by the FCC.

By January 1, 2013 all licensees must convert to and operate in at least 12.5 kHz efficiency.

By that date, you must ensure that the 25 kHz mode is disabled via software on your dual mode 25/12.5 kHz radios. And you must replace all radios only capable of operating at 25 kHz efficiency.

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 Motorola equipment is 12.5 kHz capable?
All Motorola radio equipment certified by the FCC since February 14, 1997 is 12.5 kHz efficiency capable. To review the list of Motorola 12.5 kHz capable products please see the chart on the following pages or contact us.

How do I upgrade my existing 12.5 kHz capable equipment?
In most cases, we can use Motorola Customer Programming Software (CPS) to reprogram your subscriber and base station radios to operate at 12.5 kHz. Typically, infrastructure site equipment (duplexers, Multicoupler, window filter) does not require any changes. Please contact us if you need technical assistance.

If I need to upgrade equipment, do I need to implement digital equipment?
No. Licensees can operate in either analog or digital formats as long as you operate at 12.5 kHz efficiency. Motorola 12.5 kHz efficiency equipment is available in both analog and digital formats.

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.

If I currently have a license for a 25 kHz channel, will I automatically be entitled to license two 12.5 kHz channels?
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 any additional 12.5 kHz channels to the FCC through a certified frequency coordinator.

Will migration to 12.5 kHz change my system coverage area?
Maybe. We can help you conduct tests during conversion to ensure your system continues to provide similar coverage. Please contact us to help you determine if transmitter site changes or additions will be required to compensate for possible coverage change.

How can I determine if I have a valid FCC license?
Please contact us.

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.

Does Motorola offer 6.25 kHz efficient products?
For those licensees who want to voluntarily move to 6.25 kHz efficiency, Motorola is currently shipping two complete product families that already meet a 6.25 kHz equivalent efficiency mode. ASTRO® 25 product line for Mission Critical Subscribers and MOTOTRBO™ product line for Commerce and Enterprise clients. Both operate at two voice paths in a 12.5 kHz channel, using a Time Division Multiple Access (TDMA) protocol. This technology allows you to double the capacity of your existing 12.5 kHz or 25 kHz channel.

Where can I get additional help?
For more information on Narrowbanding, please contact us.