Narrowbanding Rules

I. Impacted Bands
Part 90 Frequencies in the following Bands:

1. VHF – 150-174 MHz
2. UHF – 450-470 MHz
3. UHF – 421-430 MHz (Detroit, Buffalo and Cleveland)
4. UHF – 470-512 MHz in largest urban areas

II. Spectrum Not Included in This Proceeding

1. Part 22 Frequencies
2. Paging-Only Frequencies Are Excluded:
   1. VHF Public Safety – 152.0075 and 157.4500 MHz;
   2. VHF and UHF Business/Industrial Paging Only Frequencies;
3. 800/900 MHz Public Safety/Business/Industrial Pool Channels;
4. 700 MHz Public Safety channels (handled in another proceeding);
5. Important Notes:
   1. 163.250 MHz MUST be narrowbanded – See Detroit Medical Center, DA 07-1075, released March 7, 2006; Report and Order, ET Docket No. 04-243, released March 11, 2005.
   2. Paging systems operating on voice channels must narrowband!
6. Marine Operations
7. Amateur Radio Service

III. Chart Of Deadlines

IV. Equivalent Efficiency

12.5 kHz Equivalent Efficiency

1. Voice Operations
   1. One Voice Channel Per 12.5 kHz of Bandwidth
   2. Two Voice Channels Per 25 kHz of Bandwidth
2. Data Operations
   1. 4800 Bits Per Second Per 6.25 kHz of Bandwidth
   2. 9600 BPS Per 12.5 kHz of Bandwidth
   3. 19,200 BPS Per 25 kHz of Bandwidth

6.25 kHz Equivalent Efficiency

1. Voice Operations
1. One Voice Channel Per 6.25 kHz of Bandwidth
2. Two Voice Channels Per 12.5 kHz of Bandwidth
3. Four Voice Channels Per 25 kHz of Bandwidth
2. Data Operations
1. 4800 Bits Per Second Per 6.25 kHz of Bandwidth
2. 9600 BPS Per 12.5 kHz of Bandwidth
3. 19,200 BPS Per 25 kHz of Bandwidth

V. Trunking At VHF And UHF
Trunking is permitted pursuant to Section 90.187. There are two types of trunking: (1) Decentralized, meaning that the system does not have exclusive use of the channels(s) and therefore must monitor the channel for co-channel traffic prior to transmission; and (2) Centralized, meaning that the system has exclusive use of the channels, and therefore the system does not need to monitor the channel for co-channel traffic prior to transmission. There are also mixed systems, with some channels exclusive (and used for control channels) and some channels shared. Only channels with a service code of FB8 (for infrastructure) and MO8 (for mobile units) received co-channel protection. Co-channel protection is not available for conventional and data systems.

VI. LMCC Frequency Coordination Guidelines
The Land Mobile Communications Council (LMCC) is an umbrella group consisting of all of the private land mobile radio frequency coordinators. LMCC members cooperated in creating a series of coordination guidelines to be used for coordinating disparate systems operating on adjacent frequencies where there is spectral overlap. Primarily, the guidelines involve taking the current co-channel overlap guidelines, and “de-rating” the criteria to reflect the additional protection gained from channel offsetting. Below are the de-rating factors in a chart with regard to the introduction of 6.25 kHz systems into the VHF and UHF Bands:

6.25 kHz vs. Adjacent 12.5 kHz

For More Information
on how we can help, email
us or contact Alan Tilles at
(301) 231-0930

Sponsorship provided by