Public Safety Advocate: Broadband and/or LMR Yet Again, Self-Powered Cell Sites, Vision Summit

There is a great deal of activity in the world of public safety today. The Public Safety Communications Research (PSCR) organization, which is part of the National Institute of Science and Technology (NIST) just wrapped up its week-long stakeholders meeting in San Diego, APCO, which will be held in Anaheim, Calif., is only two short months away, and the Visions Summit (see below) will be held in September. Even so, some topics keep coming around over and over again. 

This time it is push back from a local government because the public-safety community wants and needs a new Land Mobile Radio (LMR) system, but that’s not all. They will need more tower sites to provide the coverage that is needed. The local government is trying to make a case for switching public safety to broadband-only and not spending the money on a new LMR system.

Unfortunately, this type of financial argument in opposition to LMR systems keeps coming up. As more and more agencies add FirstNet to their communications capabilities, elected officials who, for the most part, have never ridden in a police car on a Friday night, been anywhere near a wildland fire, or even ridden with a paramedic team that has to administer aid to a number of victims of a major traffic accident. 

What elected government officials do know is that they use their smartphone every day and can communicate with anyone simply by dialing a phone number or sending a text, and they can stream video and view pictures. What else do first responders need and why? During the run-up to FirstNet, we had to answer the same questions from Members of Congress and their staffs. Then there was a small earthquake in Northern Virginia. No one at the Capital could make a phone call or even send a text message. That timely little quake demonstrated that priority and pre-emption is a must-have and public safety still needs land mobile radio. 

I had been receiving calls and/or emails about once a month from both public-safety personnel asking how they can convince government officials they need both LMR and broadband, and government officials asking why they need LMR when they have broadband. It seems this topic has once again found its way to those within governments who hold the purse strings for the first-responder community. 

Why does public safety need two different types of communications networks?

As a starting point, I am reprinting below my compare and contrast chart for LMR and broadband that was first published in the Advocate on March 25, 2021.

LMR and FirstNet Attributes

CoverageLocal, Regional, StatewideU.S. Nationwide plus Territories
Type of InformationPush-to-Talk Voice: Analog, P25 Conventional, P25 Trunked (some data)Dial-Up Voice, Push-to-Talk, Text, Photos, Data, Video
DevicesMobile, Handheld LMR DevicesSmartphones, Tablets, Mobile Routers
Spectrum Low-band, VHF, UHF, T-Band, 700-800LTE Band 14, All LTE/5G AT&T Spectrum
System TypesSimplex, Repeater, Simulcast, TrunkingLTE Broadband 
PTT SystemsCommon but by TechnologyAt Present, 7 Vendors (1 MCPTT)
InteroperabilityDepends on Spectrum/TechnologyBasic Network Yes, PTT and Apps Not Yet (see Notes)
Device Tx PowerMobile: 50-100 Watts, Handheld 2-5 Watts, External AntennasBasic: 250 Mw (1/4-Watt) Built-In Antennas, Band 14 Only 1.25 Watts
Rx-Tx MatchingGood, may require Satellite Receivers Network Matched Very Well
In-Building CoverageGood to first wall, many buildings have Distributed Antenna Systems Good to first wall, Inbuilding Build-Out in Progress
Handheld Battery LifeNormally One 8-Hour Shift+, Removable and Replaceable Batteries. Rapid Charging AvailableVery Good, Well More than a Shift, Removable Batteries from only a Few Vendors. Fast Charge Available
Voice Security (see notes)Poor on Analog, Better on P25 Conventional, Better on P25 TrunkedFirstNet Fully Encrypted, Secondary Encryption Available as Needed
Site HardeningMost Sites HardenedSites Hardened as Deployed
Power Back-UpBatteries and Generators Are CommonPrime Sites, Yes, Others as Needed
Backhaul Radio, T-1 Copper, Microwave, FiberFiber/Microwave, Satellite in Rural Areas
Network ResilienceSeveral Layers of Degradation Ending with SimplexVulnerable to Site Failure but Designed for Site Overlap, No Simplex 
Failure RecoveryMost Do Not Have Back-Up Systems to Replace Failed SitesFirstNet Deploys Cells on Wheels, In Air, and Other Devices to Restore Service
Investment RequiredBuy and Own System and Devices, Pay for RepairsFirstNet: System Provided; Device Pricing Varies with Device Type
Network CoreAnalog FM – NoneMultiple-Redundant Cores
 P25 Conventional – None 
 P25 Trunked – One Central Core OR 
 Cores Located at Each Site 
 Range Extension  Vehicular Repeaters (AKA Pac-Rat)    Vehicle router using Wi-Fi to devices, High Power on Band 14 only

Notes:  A number of items do not lend themselves to charts very well, and I did not delve into detailed technology specifications for the various networks as this column is intended to highlight operational similarities and differences. 

Most Important Differences (Today)

Land Mobile Radio systems have been used as local, regional, and statewide systems for many decades. During this time, most LMR networks were expanded to provide coverage for local agencies where needed, especially as metro areas and suburbs continued to grow. While coverage for FirstNet/broadband has expanded over the last few years, LMR usually covers the local area better because it has been built out to serve local agencies. Another factor is that LMR systems use much higher transmit power in both handhelds and mobile devices. 

The Bottom Line

From the 1930s until a few years ago, only push-to-talk voice was available to public safety. Starting in the 1980s, it was possible to send and receive short bursts of text data, and starting in 2000, cellular systems adopted broadband (3G followed by 4G LTE) and agencies began putting broadband services through its paces. In the early days, they found that broadband capabilities added new ways to move data, text, images, and even videos to and from the field. However, they also discovered that there were times when cellular systems were so congested that public safety could not access the networks. 

After years of public safety working with several federal organizations and Congress, FirstNet was authorized in 2012. The FirstNet Authority awarded a contract to AT&T to be the private partner in what has become the most successful large-scale public/private partnership to date. This was followed in 2017 by the first year of the contract with AT&T to build, operate, and maintain the Nationwide Public Safety Broadband Network (NPSBN). The most significant difference for public safety is that from day one, FirstNet users had complete pre-emption and priority on the FirstNet network (and AT&T’s spectrum). Pre-emption and priority enable first responders to access the network when and if it is congested, thus negating previous access issues.

FirstNet/broadband added many capabilities for the public-safety community including dial-up calling, text, push-to-talk over broadband, transmission of images and video to and from the field and, of course, the ability to send and receive high-speed data.

From the beginning of FirstNet/broadband, a faction made up almost entirely of elected officials started thinking about abandoning their agency’s LMR system and relying entirely on FirstNet. On the public-safety side there was, and still is, a very different view. Public safety not only wants to keep its LMR systems, it wants to update them. More and more of today’s LMR systems are being integrated with/or connected to FirstNet at least for push-to-talk. This results in a great combination of two diverse networks that can back up each other and provide instant access to LMR PTT services, which is still public-safety’s lifeline to call for assistance in dangerous situations.

Ultimately, there should be three networks in place for public safety: Next-Generation 9-1-1 (NG911) for incoming calls, pictures, video, and other data; FirstNet, the network for receiving incoming information that can be sent from the dispatch center directly to responding units; and LMR, which will continue to serve multiple functions. Today, LMR networks are important because they are the only networks that support off-network communicate when all their networks are down, when they are out of range of the networks, and probably what is most important is when they need to talk to other responders deep inside buildings, sub-basements, and parking structures. Public safety needs and deserves these three networks to protect all of us and themselves.  


Redundancy and the ability to communicate under extreme conditions needs to be taken into consideration. LMR is designed for what I call “Graceful Degradation.” This means if an LMR radio site fails for some reason, there are several ways to maintain LMR communications. The first is the fallback from P25 trunking to repeater-based communications. Should repeaters at the various sites fail, the final level of fallback is for each LMR user is simplex or off-network one-to-one and one-to-many voice communications. 

Cellular broadband systems do not provide for graceful degradation today though there are ways to replace coverage of a failed cell site. Coverage of one cell site can sometimes be replaced by increasing neighboring cell site coverage. In the case of FirstNet, more than one-hundred deployable devices are ready to be set up to replace lost FirstNet coverage, extend FirstNet coverage into an area not normally covered, or where public-safety traffic is temporarily increased due to an incident.

Today, and well into the future, the most significant difference between LMR and FirstNet/broadband is that FirstNet/broadband is not capable of off-network, unit-to-unit communications. A number of vendors are working on a solution, but off-network communications are not possible today. The Mission Critical Magazine issue being readied for the APCO conference will include an article I wrote about the current status of off-network LMR and broadband communications along with a set of tests I believe will need to be passed before public safety can count on off-network broadband communications. 

Redundancy is very important and it is a focus of FirstNet. FirstNet has added more generators and battery back-up to cell sites than ever before. Still, if a cell site or a group of sites goes down for any reason, there is no way for smartphones and tablets to communicate in that area. Having two networks up and running (FirstNet and LMR) that are, hopefully, able to cross communicate adds a new level of redundancy for the public-safety community. 

FirstNet and other broadband networks are protected against deliberate attacks from outside but as we become better at protecting our networks, so do the bad actors trying to wreak havoc with them. I often think about the possibility of a regional or even nationwide outage of one or more broadband networks. If FirstNet/broadband is the only network public safety can access, a failure caused from the outside could be a real issue. Which is yet another reason I believe LMR systems should remain available for many years to come. LMR features a level of redundancy that will provide reliable push-to-talk voice communications, at least in an agency’s local area, but not everything FirstNet brings to public safety in the way of dial-up voice, text, video, pictures, and data. 

I, among others, do not believe any city, county, state, or federal organization should even consider abandoning its LMR network and moving to FirstNet only. Over time, FirstNet and the industry as a whole will continue to make progress on redundancy and other point-of-failure issues, but I continue to believe in having a second network in place to provide back-up communications and, in many cases today, still have prime communications for public safety.   

I see the greatest issue in financial considerations that could severely impact public-safety communications should not be made by non-public-safety personnel. I have said many times that if there ever comes a time when it is possible to move all of your public-safety communities to FirstNet, the decision must be made by the Chiefs and executives within the public-safety agencies and not by elected officials who have no real understanding of the need for reliable communications for public safety. 

Self-Powered Cell Sites

Today, cell sites that do not need commercial power to the site are being developed. Last week’s Inside Towersreported on a company that has developed a design for a self-powered and fully off the grid cell site. 

Aradatum is a spin-off of parent company Clean Green Energy (CGE). CGE specializes in self-powered infrastructure technology; Aradatum is the company’s venture into the cell tower arena.” The self-powered cell towers should be able to process LTE, 5G, CBRS, private networks, FWA, neutral host applications, and edge computing functions. “Our towers completely redefine where a cell tower can go and how they’re powered.”

Aradatum’s website explains in more detail how this off-the-grid cell tower is powered and its three elements including a wind turbine. Several off-the-grid cell sites I was involved with were powered by solar panels with a back-up generator and batteries, but we still had outages from time to time. This new approach brings a new dimension to what is currently being done to power off-grid communications sites. 

Vision Summit

The Vision Summit will be held in Las Vegas September 19-23, 2022. This Summit is sponsored and produced by the Public Safety Broadband Technology Alliance and it is shaping up to be a great event with exhibits and sessions. The description on the website is as follows: “The Vision 2022 Summit is a FirstNet users conference with a mission to ensure every organization and person involved in safety, security, emergency, and crisis response has the tools, technology, and knowledge they need to keep themselves and their communities safe.

The content is targeted for all FirstNet Eligible users, their Technical Support teams, and Administrative Leadership. Primary and Extended Primary users include First Responders, Dispatch, Emergency Planning, Management Teams, and all First-Responder Supporting Agencies and Services (hospitals, transportation, public utilities, and other agencies providing critical support to an incident).”

I will be providing more details in future Advocates. Do you know where you will be beginning on September 19? Join me at the Vision Summit! I hope to see you there.

Winding Down


Look up! Little Low Earth Orbiting satellites (LEOs) are being launched by the hundreds and now Virgin Media 02 has partnered with Swiss drone company Fotokite to test 5G-enabled tethered drones to provide Internet access to areas of the world that are difficult to cover. I have not yet tried a Little Leo service to see how well it works, but I will say I was impressed when Starlink started providing its ground stations in Ukraine. Now it appears satellite communications are playing an important role in the Ukrainian war. 

Broadband for rural America is advancing slowly and apparently without guidance. I keep wondering how much of the $Billion allocated for projects to close the digital divide will end up as very expensive fiber to the premise and how much will be used for what is really needed, which is a combination of fiber and wireless communications systems. 

Meanwhile, it seems the Federal Aviation Administration (FAA) has given up trying to convince the Federal Communications Commission (FCC) to work together to mitigate questions surrounding airborne altimeters. The FAA sent out a recommendations document to the aviation community to upgrade their altimeters to make sure they are working properly. 

Some states are now asking the FCC for some spectrum in the upper 5.9-GHz band. It seems at least three states want to use this spectrum for what appears to be a rebirth of call boxes. Most people have cell phones and most roads have cellular coverage, so I have not figured out why this spectrum is needed. It appears to be only one of the requests the FCC is receiving for additional or new spectrum. This poses a number of issues for the FCC and existing spectrum license holders whose spectrum may, like the 6-GHz band, be used for both licensed and unlicensed communications with little if any way to deal with potential interference. 

In the next few weeks, I will be revisiting High-Power User Equipment (HPUE) for use on the FirstNet (Built with AT&T) network, but only in the public-safety 700-MHz spectrum known as Band 14. I will also be updating what we continue to learn from our drive tests. Since I can no longer drive due to my sight impairment, one of my folks in the Ventura/Santa Barbara area has been running tests for a few of our clients. Once we have delivered our reports to them, I will share more actual drive data here. Sadly, once this work is concluded, my car will be stripped of all the communications equipment and sold. 

I want to thank Sierra Wireless for providing an MG90 router and Airgain for providing one of its AirgainConnect antenna systems that includes high-power Band 14. With this equipment, we were able to measure and record coverage from Verizon, FirstNet, and FirstNet MegaRange™ and provide detailed coverage maps. In addition to the broadband equipment, L3Harris provided an XL-200M mobile radio, which I believe is the best of the best for LMR interoperability since it provides coverage for VHF, UHF, T-Band, 700 snf, 800-MHz spectrum, and 900-MHz mostly for utility companies using the LTE system in that band. This radio also has FirstNet LTE built in, and for those still using the 30-MHz to 50-MHz band, it comes with a receiver and an exciter that can drive an RF amplifier and provide full low-band coverage. 

Some of this equipment will be relocated to a vehicle in Southern California so, hopefully, we will be able to provide additional drive-testing services. If your agency is still trying to decide which broadband network or networks you need to be using, there is nothing better than actual drive test results where all of your choices can be captured and recorded in real time.  

Until next week… 

Andrew M. Seybold, Sr.
©2022, Andrew Seybold, Inc.


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