Narrowbanding FAQs
Wednesday, May 26, 2010 | Comments
Photo courtesy Tait Radio Communications
FCC officials agreed to answer technical questions submitted by MissionCritical Communications readers. Following are questions from readers and answers from FCC technical and policy experts.
Question: If an existing license has wideband and narrowband designations for the same frequency, will the FCC automatically drop the wideband (leaving the narrowband) and issue a revised license after Jan. 1, 2013, or will the license holder be responsible for the wideband emission deletion and for requesting a revised license?
Answer: Licensees with both wideband and narrowband emission designators are not required to take any action to delete wideband emission designators to demonstrate compliance with the Jan. 1, 2013, deadline

Question: Will any license, containing frequencies that are affected, that has only wideband emissions be automatically canceled after Jan. 1, 2013?
Answer: No. The rules permit narrowband equivalent (such as two or four slots in a 25-kilohertz channel, or 4,800 bits per second per 6.25-kilohertz for data) after Jan. 1, 2013. Therefore, licenses that have only wideband emissions will still be valid for such operations.

Question: Do systems now operating as wideband digital networks (20K0F3D) qualify to remain wideband through Jan. 1, 2013, by meeting the efficiency standard if operating at 19.2 kilobits per second (kbps)? And if so, are any notifications to the FCC or other license modifications required?
Answer: After Jan. 1, 2013, licensees may operate with an authorized bandwidth exceeding 11.25-kilohertz only if they operate with equivalent efficiency (such as two or four slots in a 25-kilohertz channel for voice or 4,800 bits per second per 6.25-kilohertz for data).

Question: Is it legal to continue using legacy equipment designed for 25-kilohertz operation after Jan. 1, 2013, by adjusting its modulation to meet the 12.5-kilohertz requirements of narrowband emissions?
Answer: No. To be compliant with the commission’s rules, the radio must be specifically certificated for narrowband use under Part 90.

Editor’s Note: If you have a technical question regarding VHF or UHF narrowbanding, e-mail, and we will request an answer from the FCC and run the information as soon as possible. For more narrowbanding information, visit
You can also contact the FCC directly via Robert Kenny, FCC spokesman, 202-418-2668, In addition, visit the FCC's Narrowbanding FAQs here. Also see Tech Topic 16: Narrow Banding Public Safety Communication Channels and Tech Topic 12: National Interoperability Channels. The FCC's spectrum home page is at

For more on narrowbanding...
Click here for "Narrowbanding FAQs" from April 5.
Click here for "Narrowbanding FAQs: Week of Feb. 15."
Click here for "More Narrowbanding FAQs" from Feb. 2.
Click here for "Narrowbanding FAQs: The FCC Responds to Readers' Questions."
Click here for "Narrowbanding: Helpful Tips from Spokane."
Your comments are welcome, click here.


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