https://urgentcomm.com/wp-content/themes/ucm_child/assets/images/logo/footer-new-logo.png
  • Home
  • News
  • Multimedia
    • Back
    • Multimedia
    • Video
    • Podcasts
    • Galleries
    • IWCE’s Video Showcase
    • Product Guides
  • Commentary
    • Back
    • Commentary
    • Urgent Matters
    • View From The Top
    • All Things IWCE
    • Legal Matters
  • Resources
    • Back
    • Resources
    • Webinars
    • White Papers
    • Reprints & Reuse
  • IWCE
    • Back
    • IWCE
    • Conference
    • Special Events
    • Exhibitor Listings
    • Premier Partners
    • Floor Plan
    • Exhibiting Information
    • Register for IWCE
  • About Us
    • Back
    • About Us
    • Contact Us
    • Advertise
    • Terms of Service
    • Privacy Statement
    • Cookie Policy
  • Related Sites
    • Back
    • American City & County
    • IWCE
    • Light Reading
    • IOT World Today
    • Mission Critical Technologies
    • TU-Auto
  • In the field
    • Back
    • In the field
    • Broadband Push-to-X
    • Internet of Things
    • Project 25
    • Public-Safety Broadband/FirstNet
    • Virtual/Augmented Reality
    • Land Mobile Radio
    • Long Term Evolution (LTE)
    • Applications
    • Drones/Robots
    • IoT/Smart X
    • Software
    • Subscriber Devices
    • Video
  • Call Center/Command
    • Back
    • Call Center/Command
    • Artificial Intelligence
    • NG911
    • Alerting Systems
    • Analytics
    • Dispatch/Call-taking
    • Incident Command/Situational Awareness
    • Tracking, Monitoring & Control
  • Network Tech
    • Back
    • Network Tech
    • Interoperability
    • LMR 100
    • LMR 200
    • Backhaul
    • Deployables
    • Power
    • Tower & Site
    • Wireless Networks
    • Coverage/Interference
    • Security
    • System Design
    • System Installation
    • System Operation
    • Test & Measurement
  • Operations
    • Back
    • Operations
    • Critical Infrastructure
    • Enterprise
    • Federal Government/Military
    • Public Safety
    • State & Local Government
    • Training
  • Regulations
    • Back
    • Regulations
    • Narrowbanding
    • T-Band
    • Rebanding
    • TV White Spaces
    • None
    • Funding
    • Policy
    • Regional Coordination
    • Standards
  • Organizations
    • Back
    • Organizations
    • AASHTO
    • APCO
    • DHS
    • DMR Association
    • ETA
    • EWA
    • FCC
    • IWCE
    • NASEMSO
    • NATE
    • NXDN Forum
    • NENA
    • NIST/PSCR
    • NPSTC
    • NTIA/FirstNet
    • P25 TIG
    • TETRA + CCA
    • UTC
Urgent Communications
  • NEWSLETTER
  • Home
  • News
  • Multimedia
    • Back
    • Video
    • Podcasts
    • Omdia Crit Comms Circle Podcast
    • Galleries
    • IWCE’s Video Showcase
    • Product Guides
  • Commentary
    • Back
    • All Things IWCE
    • Urgent Matters
    • View From The Top
    • Legal Matters
  • Resources
    • Back
    • Webinars
    • White Papers
    • Reprints & Reuse
    • UC eZines
    • Sponsored content
  • IWCE
    • Back
    • Conference
    • Why Attend
    • Exhibitor Listing
    • Floor Plan
    • Exhibiting Information
    • Join the Event Mailing List
  • About Us
    • Back
    • About Us
    • Contact Us
    • Advertise
    • Cookie Policy
    • Terms of Service
    • Privacy Statement
  • Related Sites
    • Back
    • American City & County
    • IWCE
    • Light Reading
    • IOT World Today
    • TU-Auto
  • newsletter
  • In the field
    • Back
    • Internet of Things
    • Broadband Push-to-X
    • Project 25
    • Public-Safety Broadband/FirstNet
    • Virtual/Augmented Reality
    • Land Mobile Radio
    • Long Term Evolution (LTE)
    • Applications
    • Drones/Robots
    • IoT/Smart X
    • Software
    • Subscriber Devices
    • Video
  • Call Center/Command
    • Back
    • Artificial Intelligence
    • NG911
    • Alerting Systems
    • Analytics
    • Dispatch/Call-taking
    • Incident Command/Situational Awareness
    • Tracking, Monitoring & Control
  • Network Tech
    • Back
    • Cybersecurity
    • Interoperability
    • LMR 100
    • LMR 200
    • Backhaul
    • Deployables
    • Power
    • Tower & Site
    • Wireless Networks
    • Coverage/Interference
    • Security
    • System Design
    • System Installation
    • System Operation
    • Test & Measurement
  • Operations
    • Back
    • Critical Infrastructure
    • Enterprise
    • Federal Government/Military
    • Public Safety
    • State & Local Government
    • Training
  • Regulations
    • Back
    • Narrowbanding
    • T-Band
    • Rebanding
    • TV White Spaces
    • None
    • Funding
    • Policy
    • Regional Coordination
    • Standards
  • Organizations
    • Back
    • AASHTO
    • APCO
    • DHS
    • DMR Association
    • ETA
    • EWA
    • FCC
    • IWCE
    • NASEMSO
    • NATE
    • NXDN Forum
    • NENA
    • NIST/PSCR
    • NPSTC
    • NTIA/FirstNet
    • P25 TIG
    • TETRA + CCA
    • UTC
acc.com

Legal Matters


Commentary

Avoid getting into a box

Avoid getting into a box

Because some users perhaps are not properly installing trunked systems — therefore causing significant interference — this is a good time to review the FCC's rules on VHF/UHF trunking.
  • Written by
  • 1st April 2012

As narrowband radio systems are taking hold in the marketplace, more and more users are deploying trunked radio systems, in many cases using digital transmission technologies. However, because some users perhaps are not properly installing trunked systems — therefore causing significant interference — this is a good time to review the FCC's rules on VHF/UHF trunking.

Essentially, there are two types of trunking that may be employed on the Part 90 VHF and UHF channels: centralized and decentralized. Centralized is a traditional trunked system that requires exclusive use of a channel. In contrast, decentralized does not require exclusive use of a channel, but rather requires one to enable monitoring on the shared channel to ensure that the system is locked out when co-channel emissions are detected.

In the FCC's words (from 1998), "[I]n a decentralized trunked system, which is also a system of dynamic channel assignment, the mobile units continually monitor the system's assigned channels until an unused channel is found. This channel is then utilized for communications."

Section 90.187 of the commission's rules provides that centralized trunking requires either that your interference contours do not overlap with the service contours of co-channel and adjacent channel licensees, or that you obtain their consent to the trunking. The spectral separation necessary is listed in Section 90.187(b)(2) of the rules. In addition, you should consult the frequency coordination guidelines established by the Land Mobile Communications Council (LMCC) to determine adjacent channel overlap.

If you fail to achieve exclusive use on your frequencies, you must employ decentralized trunking. For trunked systems that require a control channel, it is advisable to find at least one channel in the system that is available for exclusive use, and employ that channel as the control channel. In some cases, users have asked the FCC for permission to combine shared Part 90 channels with exclusive Part 22 frequencies, to create a trunked system with exclusive channels for control and non-exclusive channels with monitoring.

On Dec. 7, 2001, the FCC issued a public notice about VHF/UHF trunking on shared channels. The commission was very clear that licensees "must employ equipment that prevents transmission on a trunked frequency if a signal from another system is present on that frequency."

The question often is asked, what kind of monitoring is required to be compliant? While the commission stated that "[t]he level of monitoring must be sufficient to avoid causing interference to other systems," it left it to the frequency coordinators to decide what level of monitoring is sufficient in individual cases. In response, the LMCC developed a guide that specifies two levels of monitoring. They are:

  • Level 1 monitoring. The repeater (base station) will monitor the input channel for transmit signals coming from co-channel mobile and portable units. The corresponding repeater output channel will be disabled during the co-channel mobile or portable unit's transmission.
  • Level 2 monitoring. The repeater (base station) will monitor the output channel for transmit signals coming from co-channel base stations. The corresponding repeater output channel will be disabled during the co-channel base station's transmission.

The first monitoring option is the default. However, frequency coordinators may elect the second option in the proper circumstance.

Systems that have channel exclusivity (or impacted licensee consent) are identified easily. Each exclusive channel must have an "FB8" station class code. Only these identified channels are entitled to use centralized trunking.

Licensees failing to follow these rules are subject to enforcement action by the FCC. Make sure that your implementation is done properly.

What do you think? Tell us in the comment box below.

Alan Tilles is counsel to numerous entities in the private radio and Internet industries. He is a partner in the law firm of Shulman Rogers Gandal Pordy & Ecker and can be reached at [email protected].

Tags: Regulation Trunking Commentary FCC Land Mobile Radio Policy Legal Matters Commentary

Most Recent


  • AT&T wireless growth keyed by FirstNet—now provides 24,000 agencies with 4.4 million connections
    AT&T this week reported that FirstNet ended 2022 supporting more than 24,000 public-safety agencies with “about” 4.4 million connections, including 377,000 connections that were added during the last three months of 2022—a total that represents more than half of the carrier’s post-paid wireless growth for the quarter. AT&T officials released these figures in conjunction with […]
  • Report: Remote work causing offices to empty, but walkable cities still in high demand
    Given the reliance on vehicular transportation in the United States, some American cities historically haven’t prioritized being walkable in past planning and or design. But amid an unprecedented shift in the economy toward remote work, those that have are increasingly desirable for prospective residents. A new report from Smart Growth American and Places Platform, “Foot Traffic Ahead […]
  • Federal agencies infested by cyberattackers via legit remote-management systems
    It has come to light that hackers cleverly utilized two off-the-shelf remote monitoring and management systems (RMMs) to breach multiple Federal Civilian Executive Branch (FCEB) agency networks in the US last summer. On Jan. 25, the Cybersecurity and Infrastructure Security Agency (CISA), National Security Agency (NSA), and Multi-State Information Sharing and Analysis Center (MS-ISAC) released […]
  • How 5G is making cities safer, smarter, and more efficient
    It’s a scenario we’ve all experienced: an ambulance with a blaring siren racing against time to get a person in medical distress to a hospital through traffic. What we don’t see is 5G connectivity enabling paramedics to communicate with hospital staff via video conference and coordinate care in real-time before arriving at the emergency room. […]

Related Content

Commentary


How 5G is making cities safer, smarter, and more efficient

26th January 2023

3GPP moves Release 18 freeze date to March 2024

18th January 2023

Do smart cities make safer cities?

  • 1
6th January 2023
view all

Events


UC Ezines


IWCE 2019 Wrap Up

13th May 2019
view all

Twitter


UrgentComm

AT&T wireless growth keyed by FirstNet—now provides 24,000 agencies with 4.4 million connections dlvr.it/ShY5qH

27th January 2023
UrgentComm

Report: Remote work causing offices to empty, but walkable cities still in high demand dlvr.it/ShXM7Z

27th January 2023
UrgentComm

AT&T FirstNet unleashes robotic dogs for emergency services dlvr.it/ShW7p8

27th January 2023
UrgentComm

Federal agencies infested by cyberattackers via legit remote-management systems dlvr.it/ShVhn3

26th January 2023
UrgentComm

How 5G is making cities safer, smarter, and more efficient dlvr.it/ShVS1h

26th January 2023
UrgentComm

MCPTT interworking for critical communications dlvr.it/ShTm3P

26th January 2023
UrgentComm

Self-driving cars present terrorism risk, FBI director says dlvr.it/ShTTHx

26th January 2023
UrgentComm

UK Home Office officially will cut ESN ties with Motorola Solutions in December dlvr.it/ShNjfN

24th January 2023

Newsletter

Sign up for UrgentComm’s newsletters to receive regular news and information updates about Communications and Technology.

Expert Commentary

Learn from experts about the latest technology in automation, machine-learning, big data and cybersecurity.

Business Media

Find the latest videos and media from the market leaders.

Media Kit and Advertising

Want to reach our digital and print audiences? Learn more here.

DISCOVER MORE FROM INFORMA TECH

  • American City & County
  • IWCE
  • Light Reading
  • IOT World Today
  • Mission Critical Technologies
  • TU-Auto

WORKING WITH US

  • About Us
  • Contact Us
  • Events
  • Careers

FOLLOW Urgent Comms ON SOCIAL

  • Privacy
  • CCPA: “Do Not Sell My Data”
  • Cookie Policy
  • Terms
Copyright © 2023 Informa PLC. Informa PLC is registered in England and Wales with company number 8860726 whose registered and Head office is 5 Howick Place, London, SW1P 1WG.