David Schoenberger

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APCO Survey on Cellular Interference to 800 MHz Public Safety Radio Systems

Location Agency Name Type of Service Type of System Frequency Interference Source Resolution Comments
Chandler, AZ City of Chandler Police, Fire, and Public Works Trunked 800-MHz, MDT Data 800-MHz 806-821 Nextel, and possibly others None Depending on cell site, a cone of silence may be from 200 yards to 1/4 mile.
Phoenix, AZ Phoenix Police and Fire Dept. Police and Fire Mobile Data 821-824 Nextel None Currently 3/4 mile interference radius around Nextel towers.  Boosting power to mitigate interference and Nextel experimenting with filters.
Victoria, BC Corp of the City of Victoria Police, Fire, EMS, Public Works Conventional VHF N/A Clearnet? None Portables talkout problems, static in mobiles, blocking.
Ontario, CA N/A Police, Fire, EMS, Public Works N/A N/A N/A N/A  
Richmond, CA State Department of Transportation Public Safety/Special Emergency Trunked, Analog, Voice 806-821 Nextel? None Coverage marginal when system installed.  Now significant signal on data channel but radios are unable to access trunk site (Big Rock).  Interference at Richmond/San Rafael Bridge Toll and adjacent maintenance station.
Denver, CO Denver Police Department EEB Police, Fire, EMS, and Public Works Trunked Analog and Digital Voice with MDTs 806-821 Nextel and possibly cellular None Changed frequencies many times without success.  Numerous sites cause loss of control channel.
Lakewood, CO Lakewood PD, West Metro FD Police, Fire, EMS, Public Works, Parks, College Security, and Mall Security Trunked, Analog, and Digital Voice 821-824 Nextel None Appears to have front end overload which Nextel is working on.  
Ft. Lauderdale, FL City of Fort Lauderdale Police, Fire, EMS, Public Works, and Beach Patrol Trunked 821-824 Nextel None MTS-2000 handhelds desense near Nextel Sites.
Ft. Lauderdale, FL Broward County Telecommunications Police, Fire, EMS, and Local Government Trunked, Simulcast, Voice, and Analog 806-821 Cellular sites None Noise floor raised by near-by cellular sites.  Mobiles not able to access system. Use of spectrum analyzer does not identify discrete interfering signals.
Largo, FL Pinellas County Government - Radio Division Police, Fire, EMS, and Public Works Trunked Analog Voice System 806-821 Nextel RFI addressed on case-by-case basis.  Nextel then changes frequency  
Miami, FL Information Technology Department Police, Fire, EMS, Local Government, Public Works, and Transit Trunked, Analog, and Digital N/A Nextel None Nextel has a new site that caused new coverage holes.
Orlando, FL Orange County Sheriffs Office Sheriff Analog 806/821 Trunked 806-821 Nextel OrlaVista Site None  
Stuart, FL Martin County Fire Rescue Fire and Rescue Trunked 800 821-824 N/A N/A  
Atlanta, GA Fulton County Emergency Communications Police, Fire, EMS, Public Works Trunked, Analog, Data 806-821 Cellular providers in Fulton Industrial Boulevard Area None Portables desensed in industrial blvd area
DeKalb County, GA DeKalb County Public Safety All public safety Trunked 806-821 Nextel and Southern Linc  None Both systems have frequencies adjacent to control channels.  When close to commercial site, blanks out radio.  
Douglasville, GA City of Douglasville Police, Fire, Hospital, and Public Works Trunked 806-824 Cell Towers None New holes have appeared where coverage had been present.  New cell towers installed.  Radio system operating within specifications.
Savannah, GA City of Savannah Police, Fire, EMS, Public Works, and City Motorola 800-MHz Smartzone Analog 806-824 Nextel  None Some commercial subscriber units operate only 100 kHz away from the city's control channels.  The filters on the city's equipment are maxed out.  A safety concern was expressed. Receiver desense due to frequency proximity and distance of Nextel units.
Lahaina/Kihei, HI Maui County Police Department Police, Fire, EMS, Public Works Trunked 821-824 Nextel None Noise floor raised.  Radios in vicinity of cellular transmitters are unusable
Olathe, KS Johnson County Sheriff's Office Police, Fire, EMS, Wastewater Water District, Airport, and County Bus Security Analog Trunking System and Mobile Data System. 806-824 Nextel and some other identified source. None Pulse-like interfering signal that moved randomly across three channels and caused bursts of static.
Baton Rouge, LA Louisiana State Police State Police/Other State and Federal Trunked 806-824 N/A None  
Duxbury, MA N/A           No other information provided.
Baltimore, MD N/A Police, Fire, Public Works, Schools, Highways, Utilities Trunked 806-821 Nextel None Overloading front end
Auburn and Lewiston, ME Lewiston/Auburn 911 Emergency Comm Police, Fire, EMS, Public Works, and City Digital, Motorola Astro N/A Paging, and other commercial transmissions Relocating transmitters and adding voting receivers Working with Comp Communications of Verooes, NJ
Howell, MI Michigan State Police Police, Fire, EMS, and Public Works APCO 25 Compliant Digital Trunked 821-824 Cellular 870-MHz Band None Intermittent loss of audio, garbled audio, and loss of ability of one unit to hear audio.  New monopole towers with sectorized panel arrays have been installed in area.
Gladstone, MO Gladstone Department - Public Safety Police, Fire, EMS, Public Works Conventional 806-821 Licensed Nextel tower site in Liberty None Nextel has obtained licensing on 851.4875 and 854.6375 at 1,000 watts.  These are mobile transmitter frequencies for this agency.
Cary, NC Town of Cary Police, Fire, EMS, Public Works, Inspections, and General Government Analog Trunked 806-821 N/A None Interference on one channel.
Tigard, OR WCCCA Police, Fire, and EMS MDT and Analog Trunked 806-824 Nextel None Two years of problem with a documented officer safety issue as a direct result.  Radio had out-of-range tone due to Nextel overloading portable.
Memphis, TN City of Memphis Police, Fire, EMS, Public Works, Gen. Services., Park, and Local Government. Trunked 821-824 N/A None Carrier on M859.4625. Carriers usually on control channels.
Missouri City, TX Missouri City Police Department Police, Fire, EMS, and Public Works Trunked Analog 806-821 N/A N/A  
Bellingham, WA Wiztronics, Inc (Private) Backup for public safety system Fire, Public Works Trunked, Analog, Voice N/A Nextel None Digital signals in combining stages caused broadband noise. 
Seattle, WA City of Seattle Police, Fire, EMS, Public Works SmartZone trunked system and Motorola/MDI MDT system 806-821 Nextel Site at 45th and Roosevelt None  
Seattle, WA King County Police, Fire, EMS, and Public Works Analog and Digital Trunked, MDT 806-824 Nextel  Nextel reduced power, removed some frequencies, changed antennas and uptilted new antennas  
Seattle, WA Port of Seattle Police, Fire, Maintenance, Operations Trunked 806-821 Nextel None  
Vancouver, WA Clark Regional Communication Agency PSAP, Police, Fire, EMS, Public Works, and Transit Trunked Analog, Data 806-824 Nextel None Desense within 1/4 to 1/2 mile of Nextel sites.  
Vancouver, WA WSDOT Highway Maintenance EF Johnson Multinet 806-824 Nextel site at I-205 and SR 500 None Four sites overlap area and have moderate signal levels.  Signals drop out and receivers squelch up tight.  No communications are possible in the clover-leaf.  Measured -20 dbm carriers from Nextel site about 1/4 mile away.  Several cell sites in area do 
Green Bay, WI Green Bay Police Police, Fire, EMS, Public Works, Transit, Parks Trunked 810-816          855-861 Other Public Safety Agency None  

Copyright 2012 David Schoenberger