Security snapshot: The Windy City
When it comes to security, Chicago’s public safety networks are protected by design.
The reason? Seven years ago, Chicago amalgamated the radio networks of its police, fire and EMS. Yet in doing so, the city didn’t put all its eggs into one basket. In fact, these networks are a model of decentralization, and thus difficult for terrorists to discount.
Granted, dispatch for police, fire and EMS has been centralized at the new Chicago Emergency Communications Center. (At 1400 W. Madison Street, the 161,000-square-foot CECC can handle as many as six million calls a year.) However, it is not one-of-a-kind — a redundant 9-1-1 dispatch center exists elsewhere in Chicago.
Meanwhile, the nuts and bolts of Chicago’s amalgamated radio networks are anything but centralized. The whole system is a fine example of “distributed networking,” to borrow a term from the computer industry.
“We’ve got about 125 radio sites scattered throughout the city,” said William Carter, supervisor of electronic operations for Chicago’s Office of Emergency Communications. “These are all cross-connected so that if one site suddenly goes down, traffic is automatically re-routed to the next-best transmitter.”
To put this in a Sept. 11 context, if the Sears Tower or any other major Chicago building should collapse, the city’s public safety networks would be unaffected. In contrast, the Port Authority of New York and New Jersey was seriously hurt by the World Trade Center’s collapse — in large part because the WTC was its headquarters — while the New York State Police had to scramble to re-establish radio service in the area.
Actually, the Sears Tower doesn’t even fit into the equation, said Carter, because “it’s too high” for the city’s transmission needs. “All public safety systems are designed for portable operations, so optimal height for locating radio transmitters is about 250 feet, while 150 to 200 feet up is best for receivers,” he said. That’s why the Sears Tower, with its rooftop at 1,450 feet above street level, doesn’t qualify as a public safety site.
Public safety network snapshot
With nearly three million residents and a territory spanning some 228 square miles, Chicago is a seriously big city. That’s why it takes 13,669 police officers, 4,205 firefighters and 612 paramedics to serve this region. In 2000, the Chicago Police alone handled 2,833,788 dispatches.
To do the job, “the police and EMS use UHF radios (460MHz),” said Carter, “while fire operates on VHF (154MHz). All of them operate across 27 zones: 13 police, two data network,” he said. This network supports in-car terminals within the city’s emergency vehicles. “Our police alone make a million inquiries over these terminals each month.”
In addition, the CECC can use the data network to track the whereabouts of fire trucks and ambulances at all times. As Chicago Mayor Richard M. Daley said on Oct. 22, 2001, this tracking system “allows us to reallocate our emergency resources instantly.”
Speaking of data, Chicago’s EMS service has access to a total of 24 telemetry channels (eight frequencies reused across three zones). These channels are used by paramedics to send ECG and other life-sign readings directly to the hospitals that receive emergency patients.
“We’ve modified the paramedics’ portables so that they can plug them directly to these electronic measurement devices,” Carter said. “This means they can send readings back from anywhere in the field.”
Intriguingly, Chicago’s OEC tested the performance of these EMS systems by sending paramedics deep into the Sears Tower’s lower level basement. How well did the portables send voice and data from two stories below ground? “We achieved a 95% reliable communications rate,” Carter said. “It was an impressive performance.”
Radio sites
As Carter mentioned, Chicago has a total of 125 radio sites. Most are on medium-sized buildings, he said. In fact, “only 18 are on tower structures owned by the city.”
In general, Chicago’s radio towers are three-legged, self-supporting and 250 feet tall. Thanks to consulting work by Lyncole XIT Grounding (www.lyncole.com) of Torrance, CA, the towers resist damage from lightning strikes.
Carter hired Lyncole a few years ago when he noticed that equipment at certain towers was suffering far more lightning damage than at other towers. These towers were older and so were poorly grounded because of weathered connections and obsolete grounding practices.
To say the least, this problem worried Carter. After all, these towers are interconnected into the CECC’s 200-mile-long fiber-optic network, which is augmented by 1,000 miles of underground copper. The last thing Carter wanted was to turn the CECC’s equipment into an expensive lightning resistor. So the decision was made to call in Lyncole, which specializes in detecting and fixing grounding faults.
Finally, there are the fiber optics themselves. “All of our primary transmitter sites are connected by fiber optic cables,” Carter said. “Fiber was expensive to deploy, but it gives us a measure of reliability that nothing else can match.” Add to this the CECC’s dynamic switches, which can shift feeds from one transmitter to another as required, and the result is one solid radio system.
One vulnerability exists for now
No system is perfect, of course. In the case of Chicago’s public safety networks, the problem is compatibility. Despite amalgamation, the city’s police, fire and EMS cannot talk to each other by radio. Instead, everything has to be coordinated through the CECC.
This is why — as reported in the November 2001 issue (“Chicago Blazes Affordable Path to Radio Interoperability”) — the city is developing a radio interoperability pilot project. Spearheaded by Rich Nowakowski, Chicago’s project manager for radio interoperability, the Chicago test will use six TRP-1000 transportable interconnect systems to link public safety crews in the field.
Designed to serve as a telephone-style switch, the JPS Communications-built TRP-1000 allows 10 radios and two phone lines to be plugged in, and it interconnects them all. Chicago has already built one switch into a converted 1992 Ford ambulance and will be testing it in the field soon.
Verdict? Chicago’s done it right. Chicago’s public safety networks are well-positioned to resist attack. There are no two ways about it.
“We did the right thing in amalgamating our networks in this way,” said Carter, who designed the system as an economical alternative to expensive upgrades to Chicago’s separate police, fire and EMS networks in 1990.
Even though the new design was not focused on decentralization as a security measure, decentralization is proving to be the best way to protect public safety networks against the kind of failure that can be caused by a terrorist attack.
Careless is a freelance telecommunications writer based in Ottawa, ON, Canada. His email address in [email protected].
