The FCC's Narrowbanding RegulationsOn 1 January 2013, you must transmit data in one of two narrowbanding modes:
- In 12.5 kHz channels (at any link rate)
- In 25 kHz channels at 19,200 bps
What does it mean?
ALL radios will remain legal and all licenses will remain valid as long as you transmit data in either of the above narrowbanding modes. Transmitting at 19,200 bps in the 25 kHz channel achieves the equivalent technology of transmitting at 12.5 kHz, according to the FCC. Operating in either of these narrowbanding modes will significantly reduce performance unless you use one of the new radio protocols developed for narrowbanding. The narrowbanding regulations do not affect receivers, so you can use a 25 kHz receiver with a 12.5 kHz transmitter.
Why did the FCC mandate Narrowbanding?
Public safety communications continue to evolve as more challenging user requirements and technology considerations put pressure on municipalities and their local public safety organizations to enhance and improve their systems. This evolution to other services such as data and video applications is increasing the demand for higher capacity channels and is driving the need for improved spectral efficiency for public safety spectrum allocations.
This was accomplished by reducing the single voice channel bandwidth from the traditional analog value of 25 kHz to 12.5 kHz. Data radios used in commercial applications must remain secondary to voice radios used for public safety. Not only must they operate with CSMA, on 1/1/13 they will be required to transmit either in 12.5 kHz channels (“narrow”) or at 19200 bps in 25 kHz channels (“fast”). In this way, the availability of usable channels is effectively doubled or quadrupled in the same equivalent bandwidth. Narrowbanding, as the process has become known, is being used to improve spectrum efficiency especially in the crowded VHF high (150-170 MHz) and UHF (421-512 MHz) land mobile radio (LMR) frequency bands.
All 25 kHz radios will be illegal on 1/1/13?
This is true for voice radios, but is not true for data radios. You can continue to transmit data in 25 kHz channels if you use a link rate of 19,200 bps or higher.
Does your radio operate in the 25 kHz narrowbanding mode?
Check with your supplier to determine whether your existing radio is narrowband-capable or needs replacement.
Radio license status on 1/1/13
You do not need to contact the FCC regarding existing licenses. Their expiration dates will remain unchanged and existing radios will remain legal as long as you transmit in either of the above narrowband modes. Note that on January 1, 2013, the Narrowbanding requirements will supersede the terms of any license and you will not be permitted to transmit in 25 kHz channels with a radio link rate less than 19,200 bps.
If you need a new license or wish to renew or modify an existing license, you may do so online with the FCC’s Universal Licensing Service, http://wireless.fcc.gov/uls/. If you wish to transmit in the 25 kHz / 19200 bps narrowband mode, you will be prompted to fill out a special on-line form. Your radio supplier can help you fill out this form.
How will Narrowbanding affect your system?
Operating in either Narrowbanding mode will significantly reduce the performance of older radios in either range or throughput. You should upgrade your radio to one with new technology that is designed to operate under the FCC’s upcoming Narrowbanding regulations.
Unchanged FCC Restrictions
As always, you must have a valid license to transmit, at any power level, between 421 and 512 MHz. You must set CSMA to ON so that voice transmissions have priority over data transmissions. You must configure your radios to transmit a call sign at the required frequency and speed.