Trending Topics

Keeping critical police communications fast, clear & protected

By Capt. Eddie Reyes
Sponsored by Cisco Systems

Have you ever just paused for a moment to think about what happens to your transmission after you push to talk (PTT) your radio microphone? If you stop to think about it, it’s amazing how a radio transmission in one part of a city or state can reach its destination within a fraction of a second, often traveling hundreds of miles and passing through very complex infrastructures.

Before communications and interoperability issues became a part of my life, I used to be like the average public safety professional. I never cared how it happened nor did I stop to think about it. All I knew was I would key the microphone on my radio and normally within a few moments I would get a reply from others.

I say normally because in the late 90’s something strange started happening. I started experiencing radio interference from outside sources and sometimes my radio transmissions would not go through because of competition for my assigned radio spectrum, like Joe’s Towing Services or some of the cellular telephones in use nearby, would interfere with my critical communication.

Or how about when you depress the “send” button on your mobile data computer and somehow that message you just submitted, containing lots of data, is sent to multiple locations? It does not just happen magically, but pretty close.

This month I decided to try and help others to better understand that often elusive and misunderstood term we call “radio spectrum” and some emerging technologies that are coming our way. Not that I understand it very well myself, but well enough to know that it is a precious commodity which is becoming increasingly scarce to public safety agencies across the United States, and which every department head should give very careful consideration to when planning long term communications projects.

As you know, the public today demands that we respond very effectively and efficiently to today’s events because after all, television shows like “CSI” leads them to believe we know everything about everyone all the time and communications is never a problem.

Coupled with today’s public safety officials who demand better information and communications systems in order to stay safe, you have a very challenging dilemma.

”...with advances come significant challenges towards maintaining the integrity and security of our communications systems.”

Public safety personnel simply do not tolerate poor radio systems and lack of critical information anymore. While I am not a fan of frivolous lawsuits or labor unions that bully their way into some agencies, in this case, these two have been instrumental in getting public safety better communications and information systems.

Better information and communications systems like being able to see streaming video coming from a bank being robbed on the mobile data computer of a police cruiser while the officer is enroute. Better communications systems like the state trooper who can now talk from his portable radio to another trooper in another part of the state that has a dangerous felon detained. None of this would be possible without the significant advances humans have made with the finite amount of radio spectrum that exists.

Yet with advances come significant challenges towards maintaining the integrity and security of our communications systems.

Not that long ago, public safety did not have to compete with the millions of people who now own cellular telephones, PDA’s and laptop computers that now operate on similar radio spectrum that we use everyday.

How you noticed how many cellular telephones there are around you? They are everywhere! According to CTIA, the international association for the wireless telecommunications industry, it is estimated that by the end of 2005 there were approximately 208 million cellular telephones in the US market. That is a clear example of the potential for interference with public safety communications systems, especially in very populated locations.

Radio Waves

Almost all the critical communications tools that we use daily in order to get our jobs done operate on radio waves. I’m talking about the radios on our belts, in our vehicles, our pagers, PDA’s, cellular telephones and mobile data computers.

As you well know, some are much more robust than others, but they all rely on radio waves in order to transmit or receive data. Most voice messages today are tiny digital packets of data coming across radio waves bundled neatly for seamless delivery. The reason radio waves are called “waves” is because they function very much like dropping a small rock in the middle of a perfectly still pond. When you drop the rock, the ripples (waves) begin to work outward in a series of repeating peaks and valleys until they reach the outer limits of the pond.

This pattern, before it repeats itself, is known as a “cycle” and the number times a wave repeats itself in a second is called a “frequency”.


In my April, 2006 column I briefly mentioned the public safety frequencies that range from 25 MHz to 869 MHz. The aggregate and finite amount of state and local public safety spectrum allocated within these bands is 97 MHz.

What I failed to describe was the effects that each band had out in the field.

Communications systems that operate at or close to the 25 MHz end of the spectrum are capable of reaching great distances with very little infrastructure, such as antenna or repeater sites. These radio systems were the favorite of large state agencies or large municipalities who had lots of ground to cover but could only afford little infrastructure.

While this low band of frequencies is extremely effective in covering large areas with very little infrastructure for voice communications, it is not effective in penetrating buildings and officers on foot cannot safely rely on portable radio communications in this band. Furthermore it is virtually impossible to transmit data at this end of the spectrum.

The good news for public safety regarding additional frequency availability is that twenty-four MHz in the 700 MHz band has been reallocated by the Federal Communications Commission (FCC) for exclusive use by public safety once TV channels 60-69 relinquish this band (expected to be completed by 2009). Additionally, fifty MHz in the 4.9 MHz band has been allocated for broadband data applications.

Because these are new and emerging technologies, for the most part, technical and operational standards are not in place. Fortunately, neither is the infrastructure or equipment at any government level.

Organizations like the National Public Safety Telecommunications Council (NPSTC) and the Association for Public Safety Communications Officials (APCO) are working hard to set these standards in preparation for the arrival of the infrastructure and equipment that operates in these frequency bands. There is no doubt this new technology will be purchased by public safety as funding becomes available.

This development in standards really excites me because for once, it appears that the standards will be in place before lots of the equipment and this will significantly improve the potential for interoperability using equipment in these frequency bands. This is a very different approach from the past where almost each radio vendor established their own standards for their radios and systems and they often would not work seamlessly with other vendor’s products.

Emerging Technologies

Emerging technologies in the public safety communications arena are appearing quicker than anyone expected. This is an exciting trend, because in practice, the average household has more advanced telecommunications options than most first responders.

Multi-band radios aren’t that far away. Some of these radios will operate in the 148 MHz band all the way to 512 MHz. Imagine a radio that will operate in any frequency, can be turned on and off remotely as needed, control power consumption to obtain maximum use of a battery and can augment communication with a mixed-networking software stack. Multi-band radios are virtually mini computers with an antenna capable of staying connected regardless of location and spectrum available.

“I saw this system provide chemical/biological alarm information to first responders, remote video monitoring at command sites, cross-jurisdictional database messaging, and ambulance-hospital video links.”

Here in the National Capital Region, the District of Columbia, a founding member of the Spectrum Coalition, was one of the first government agencies to be successful in obtaining a temporary license from the FCC in the 700 MHz band for public safety communications purposes. I was an honorary charter user of this system during the early pilot phase and my experience was terrific.

For starters, this spectrum allowed me to access criminal justice data at broadband Internet speed virtually anywhere in the District provided by their ten antenna sites located throughout the City.

I saw this system provide chemical/biological alarm information to first responders, remote video monitoring at command sites, cross-jurisdictional database messaging, and ambulance-hospital video links.

But as you can imagine, with emerging technologies come unintended consequences.

The interference problem and competition for the same radio spectrum between public safety and one of the major cellular providers became so severe that in 1999 the FCC brought together representatives from public safety and the commercial industry to discuss the problem aimed at adopting a plan that would separate public safety, critical infrastructure and other non-cellular users from systems that employ a cellular architecture in the band.

While the relocation process is the right thing to do in order to stop this interference, it has been a logistical nightmare for regions in the 800 MHz band.

Although it sounds simple enough, we are no closer today to rebanding than we were in 1999 when we started focusing on this problem. It has been virtually impossible to accomplish in regions that have superb interoperability in place because regions with 800 MHz users, where top level of interoperability has been accomplished at the radio level, re-banding, or reprogramming requires that all agencies (radio systems) do it simultaneously. Because if one agency reprograms to the new band and the others don’t do it simultaneously, those agencies will lose interoperability.

Some public safety agencies rely on their radio system to transmit data to their mobile data terminals. This is one reason why many large metropolitan areas have chosen radio systems in the 764 - 806 MHz range. The higher the end of the radio spectrum, the more data you are able to transmit at faster speeds in a wireless environment.

Some agencies, however, have chosen commercial wireless providers, such as Verizon, Sprint-Nextel or Sprint to provide them with spectrum for high speed broadband data. My agency has been using Verizon’s wireless network for mobile data since the late 90’s when Cellular Digital Packet Data (CDPD was debuting. Back then the best we could receive was small written messages (car-to-car, registration/wanted checks, etc).

But now that more robust wireless communication is readily available for public safety, such as CDMA (Code-Division Multiple Access), EV-DO (Evolution Data Optimized) and Wi-Max (Worldwide Interoperability for Microwave Access), multiple color photos of wanted persons and streaming video to the police vehicle is completely possible.

Cyren Call

A new development for public safety communications in the upper 700 MHz band is being proposed by a company called Cyren Call. They are proposing to build a nationwide, seamless broadband network for better public safety communications.

Their plan calls for a nationwide network that could transmit signals up to 30 miles with the potential to penetrate walls and foliage. If this development is completed, it has the potential to provide public safety nationwide coverage, reliability since it would be a private network and have redundancy.

I recommend you follow the progress of this emerging technology.


The Wi-Max Forum has designated two license bands - 2.5 GHz and 3.5 GHz. It is supposed to deliver much faster data speeds across greater distances than cellular. This type of spectrum is ideal for transferring video and hefty data loads in a challenging mobile environment.

It is predicted that Wi-Max will cover up to two miles from one base station and potentially deliver up to 12 Mbps, compared with the average128 Kbps that most cellular providers deliver today.

Just imagine being able to use a handheld device (PDA) to browse multiple criminal justice databases, including photo spreads or downloading video from a school’s security camera before entering the building.

It is anticipated that this technology will be commercially available by the end of 2007. But don’t be in a big hurry to jump on this wagon once it reaches your town. Equipment for this spectrum is scarce and untested in a public safety environment. Engineers and equipment providers don’t have the experience with Wi-Max deployments as those with today’s cellular technology, so they will be learning as they go along.

In Summary

I told you at the beginning of the article that most public safety officials take radio spectrum for granted and now you know why - it’s dry! But how in the world would we be able to function without all the wonderful technology and communications tools that we all use so much every day.

Radio spectrum is becoming increasingly scarce to public safety agencies across the United States and every department head should carefully consider the different options that exist today when planning long-term communications projects.

Remember that with advances come significant challenges towards maintaining the integrity and security of our communications systems. Those of you in the communications business know how often your systems are taken for granted until they go off the air for a split second. Like the rest of you with 800 MHz radio systems, I will be glad when the rebanding process is complete because the interference on public safety radio systems continues to grow each day.

The daily progress with the development of 700 MHz, 4.9 MHz, and Wi-Max really excites me because, in addition to being much more robust networks compared to what public safety is accustomed to, the focus on standards for these networks can only mean one thing - better interoperability.

But let’s not lose sight of the most important feature with these new developments - network security. Sure, it is exciting to think of the endless possibilities these emerging technologies will bring to public safety, but we have to remember that evil lurks around every corner.

We must triple protect our communications systems against potential hackers and never take anything for granted.

Sponsored by Cisco Systems

Capt. Reyes, Alexandria (VA) PD, is currently the Arlandria Area Commander in Alexandria. He was formerly assigned to the CommTech Program (formerly the AGILE Program), one of the most successful programs of the National Institute of Justice.

While at NIJ, he managed public safety radio interoperability operations for the City of Alexandria. Captain Reyes commanded the Emergency Communications Section of the Alexandria PD and chaired the Metro Washington Council of Governments Police Technology Subcommittee, which focuses on regional technology issues impacting law enforcement.

He chairs the VA State Interoperability Executive Committee and sits on the Law Enforcement Information Management Section of the International Association of Chiefs of Police and the US Department of Homeland Security’s SAFECOM Advisory Working Group.

Captain Reyes is a native of New Mexico and holds a Bachelor’s degree in Criminal Justice from New Mexico State University. He is presently working on his Master’s Degree in Public Administration with a concentration in Administration of Justice at George Mason University in Fairfax, VA.