by Alan Henney (

Charles County -- one of the fastest growing counties in the state -- has issued a request for proposals for a trunked radio system.  Complaints about the county's existing radio systems include dead spots in the western and southern areas of the county, chronic interference from nearby school districts, and aging equipment.

Charles County seeks to lease or purchase an 800 MHz mixed analog/digital trunked system.  The system will provide emergency call, private call, call alert, telephone interconnect, unit identification, and encryption.  The system architecture will be compliant with the Association of Public-Safety Communications Officials (APCO) Project 16 standards for public safety trunked radio systems.

Although not a requirement, the county desires the trunked system to conform with the objectives of APCO Project 25 in terms of digital modulation; interoperability with equipment from other manufacturers; ability to support at least two simultaneous messages within a single 25 KHz channel assignment through either FDMA or TDMA technology; 9600 BPS working and control channel speed; ability to support Improved Multiband Excitation (IMBE) vocoder; advanced digital encryption such as DES; superior audio clarity through advanced error correction; data interface for MDTs; and ability to expand and grow.

The county seeks a system that can be cost-effectively modified to accommodate mobile data and vehicle locator systems (AVL) in the future.

The project will include: the installation of a digital-loop microwave system to connect the antenna sites; furnishing and installing remote site and monitoring and control systems; communications center equipment; system controller and audio switch; mobiles, portables and control stations; a fire station alerting sub-system; and integration of the new system with certain existing sub-systems.

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portable coverage within all buildings within the service area with 15 dB loss characteristics.  In addition, buildings identified as "critical coverage buildings" require 95 percent portable coverage regardless of the building loss.

All existing county radio users are anticipated to migrate to the new system.  So far, a total of 25 talkgroups have been identified.  The proposed analog agencies are fire/EMS, Van Go, Building & Trade, Utilities Field Ops, meter readers, Growth Management, Zoning Management, Water & Waste, and Utilities Office.

The only planned digital users are animal control, and the sheriff, including the sheriff's road patrol, corrections and deputies assigned to the LaPlata headquarters.

The proposal calls for 267 analog mobiles, 250 digital mobiles, 379 analog portables and 249 digital portables.  All digital radios, and only digital radios, will provide encryption too.

"Spectrum efficiency," states the 138-page proposal, "is not the highest priority to the county, and it is a tertiary issue overshadowed by interoperability, audio quality and multiple equipment source concerns."

The county seeks "some level of interoperability" with other nearby public safety systems using similar technology.  In addition, the five 866-869 MHz mutual aid channels will be installed at each base site but will not operate in a simulcast manner.  A couple conventional simplex "talkaround" channels are also planned.  Charles County has coordinated eight 866-869 MHz channels.  The regional coordination committee has cleared three channels for use and the remaining five are still pending.  They are: 866.325, 866.625, 867.05, 867.45, 868.65, 868.675, 868.9 and 868.925

In the county's "give-back statement," the county promises to relinquish: 45.14, 46.1, 46.42, 46.54, 155.61/154.755, 155.535, 155.64/154.875, 155.67, 453.725 and 453.625.  Note that 46.1 is not licensed to the county (perhaps they meant 45.4, 45.64 or 46.36).  Several channels would be retained, including those used by the detention center (453.425 and 453.65).

The county plans to continue to use 158.775 for fire/EMS paging and alerting.  But the existing system

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tion (1D, 2D, 3D, etc.) has a primary dispatch position and an assistant position (on my visit, some districts only had a primary dispatcher).  Dispatchers sit in clusters organized by their regional operations commands, ROC-North (2D and 4D), ROC-Central (1D, 3D and 5D), and ROC-East (6D and 7D).  Most dispatch positions feature three monitors -- one each for CAD, mapping, and the radio system.

Dispatchers and call-takers are ready for each and every call with their Watson furniture specially designed for 9-1-1 centers.  Counter tops and consoles rest on adjustable risers so personnel have the option of sitting in "air chairs" or standing.  Foot humps permit users to rest their feet on the ground or at an angle while sitting.

An Intergraph Windows NT-based CAD system interfaces directly with mapping software with data purportedly supplied by the Naval District of Washington.

Dictaphone's Freedom Enterprise Recording System allows users to easily review the last 20 minutes and can supposedly retrieve online recordings stored from the past two years.

The Motorola Centracom Elite radio consoles are graphical-user computer interfaces that display the channels selected by the dispatcher.  Each channel appears in its own sub-window with pertinent information such as transmit/receive status, volume level, and a "show PTT ID" option that displays the PTT (press-to-talk) user ID when an officer keys a radio that has the "signaling" option enabled.  No big surprises, but here are the channels the MPD supervisor console may access.  The display actually indicates the FCC-assigned call sign.

MPD Supervisor PSCC Console Channels:
460.350 KLG604 1D DISP
460.250 KLG610 2D DISP
460.025 KLG617 3D DISP
460.500 KLG614 4D DISP
460.200 KLG616 5D DISP
460.150 KLG609 6D DISP
460.475 KLG603 7D DISP
460.325 KLG615 METRO (tunnel version of Citywide)
158.790 KRJ859 ISB (Investigative Services Bureau)
460.325 KLG615 CW (Citywide)
158.850 KLG608 CID (Criminal Investigations
460.275 KLG611 SOD (Special Operations Division)
LINE 01 and 02 (phone lines used for patching)
460.100 KLG605 TAC1
460.400 KLG613 TAC2

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460.450 KLG607 TAC3
866.3625 PMARS
460.425 KLG606 COMM (Command channel)

In the middle of the large room are the MPD call-takers.  All 9-1-1 calls are initially received by them, then may be transferred to the appropriate agency such as U.S. Park, White House, U.S. Capitol, Metro Transit, DC Fire/EMS, etc.  Instead of transferring the fire or EMS calls across town, the transfer is literally across the room, and the uniform CAD system makes it especially easy for calls that require both agencies.

A Windows NT-based Vesta phone system and automatic call distributor (ACD) directs calls to an available call-taker and transfers them if necessary to one of the other emergency agencies, AT&T Language Line Services for foreign callers, or to poison control.  A special feature automatically identifies TDD (telecommunications device for the deaf) callers and allows the call-takers to communicate directly with them using the same system.  Plantronics headsets are standard throughout the facility.

Also in the middle of the room, on the walls above the call-takers, LED screens display the number of call-takers online, and the number of calls pending by queue:  non-emergency (727-1010), 3-1-1, 9-1-1 and cellular.  In addition, call-takers' supervisors sit on a platform off to the left side in the middle of the room.

Continuing through the room from the lobby, the next set of rows include fire/medical call-takers.  They have the same equipment as MPD call-takers, however, their training is different.  They are certified EMDs (emergency medical dispatchers) through Medical Priority Consultants.  They are always the second point of contact as they would not receive an initial 9-1-1 call; their calls are transferred from the MPD call-takers.

At the far end of the room are the fire/EMS dispatchers.  Sitting in a "pod" and appear huddled together, each has the same equipment as the MPD dispatchers, but their radio consoles mostly access digital trunked system talkgroups.  The fire/EMS radio consoles feature the department's standard trunked system line-up, with a few conventional channels such as the former VHF channels used by the department.  Also included is a specially designed radio patch that connects to the Naval District of Washington's FD EDACS trunked radio system, and a private-call feature that allows the

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The Prince George's County Police Department is planning to start an 11th police sector this September.  The "W" (William) sector will be in the southern part of the county, and will cover parts of "F" and "J" sectors.  This includes Accokeek, Tantallon and portions of Brandywine.  According to the plan, each station will give up 10 officers (in effect, a squad) to the new sector.  As of this writing, sector headquarters location and channel assignment have not been finalized.

The new District 4 (Oxon Hill) police station is open at 5135 Indian Head Highway in the Eastover Shopping Center.  The sign out front reads "Eastover Police Station," though we are assured it is a county police district station!

The $40 million needed to fund the county's proposed public safety trunked radio system project was reportedly rejected by the county council.  The county intends to retain its 800 MHz channels and its two sparsely used five-channel EDACS systems, which are used by a few county police speciality units, the county's central services and a handful of local government users.

The department's Sierra Wireless mobile data modems have been suffering a few bugs.  They perform fine for a while (a week or so) and suddenly a message appears that Windows is unable to locate the modem.  Airinc, the company that installs them, tells officers to simply open the trunk and unplug the modem from power, then plug it back in again!  Hopefully a patch will be found by the time you read this.

The department still has no idea when the CAD interface will be in place so county officers can get case numbers and dispatches over the mobile data computers.  There is no plan, right now, for a direct connection with the county sheriff's warrant computer.  The plan is that, every night, the police department's server will download the open-warrant data, which officers will then query the next day.  Any hits will have to be verified with the dispatcher.  There is no plan for a live feed between the two agencies, although we are told the MNCPPC (Maryland Park) police have such a connection to the sheriff's system.

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Ellicott City.  The state plans to build the tower and share it with the county.  The tower would be part of the county's new 800 MHz communications network.  Some residents, says the June 26 Baltimore Sun, oppose construction of the tower next to the state's District Court building because it would be visible within the county seat's historic district.  Critics contend it should be built farther from the historic district.

Preservationists filed a complaint with the FCC in June requesting an extension to comment on a public document that they say officials withheld from them.  The state had planned to finish building the structure in March and wanted more than a year to test and correct any problems with the communications equipment.  The county's newest emergency communications tower is a 400-footer in Savage that was completed in June at a cost of $800,000.  Towers are to be installed in Woodstock and Ellicott City.  The county is adding a total of five new towers for its 800 MHz system which will consist of nine towers.  They hope to have the system running by late next year.

Residents discovered that they may have little recourse against a state project to build a 340-foot-tall communications tower.  As part of a project to install a statewide 700 MHz emergency communications system, and upgrade Frederick County's system at the same time, the State Highway Administration is allowing the tower to be built on Bridgeport Road land that currently houses a salt dome.  The tower, reports the July 3
Frederick News-Post, will be a three-legged, self-supporting, lattice-style tower that will ultimately support antennas for county, state, federal and local emergency communications.

The tower will join a network of five or so other locations in the county that will be interconnected using high-capacity microwave circuits.  That network will be a part of Maryland's statewide 700 MHz emergency communications system sometime around 2006.  The state seeks such partnerships with local governments to construct this network of radio towers which will create needed infrastructure for the state's 700 MHz system, while allowing local governments and state agencies to use them now.

Other proposed sites include Frederick Municipal Airport, Brunswick, Mar-Lou Ridge, Mount Airy and Gambrill.  The Emmitsburg site purportedly offers the best possible reach of signals without costing the county or state any money for rent on established towers or forc

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ing them to buy or rent land.  Maryland State Police, Maryland Institute for EMS Systems, DNR and the county's emergency communications are planning to participate.  Tower construction is scheduled to begin this fall.

FAUQUIER COUNTY NEGOTIATES RADIO SYSTEMS.  In a 3-2 vote during June, Fauquier County supervisors decided to begin contract negotiations for an 800 MHz trunked radio system.  The June 21 Fauquier Citizen Web page reports that the county shelved consideration of an alternative 150 MHz system until September.

Motorola and M/A-Com (formerly ComNet Ericsson) submitted bids on building the 800 MHz system.  The board will keep those bid prices secret during contract negotiations.  But cost estimates received by the county for an 800 MHz system have ranged from $8 million to $12 million.

One county supervisor argued that a 150 MHz trunked simulcast system left too many technical problems unanswered, suggesting that there is no similar 150 MHz simulcast trunked system in use in the public safety arena.  Virginia is developing such a system.  A six-member team of county officials and consultants will negotiate the 800 MHz system contract later this summer.  In an investigative editorial, Jim Borland challenges the idea that the 150 MHz band is unsuitable and stresses that a trunked system is overkill, and a conventional 150 MHz system would cost a fraction of the price of an 800 MHz system.  Related information can be found at:

NEW HELICOPTERS FOR BALTIMORE.  Baltimore police helicopters returned to the city's skies in July for the first time since a 1998 fatal crash grounded the unit.  The city's new police helicopters, states the July 3 Baltimore Sun, are the sleek black $1.4 million Canadian-built American Eurocopter EC-120s.  The department says each EC-120 will be outfitted with cameras with infrared and zoom lenses.  And by year's end, images from the cameras will be able to be beamed to commanders on the ground.  The copters also will have equipment that can pinpoint the locations of stolen vehicles.

Two EC-120s arrived in July and two more are expected by September.  The helicopters, which can carry up to five people, will eventually fly between 9 a.m. and 2 a.m.  The helicopters can fly about 145 m.p.h. and stay airborne for about three or four hours.  The city esti

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