2000-11-08 CC - Laserfiche WebLink

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. Monitoring of radio channels is rated a critical concern even though most law enforcement personnel have mobile data communications available that eliminates monitoring. Mobile data communications does require typing out messages, which is much slower than short voice messages between personnel and is only a partial solution to the monitoring problem. The law enforcement questionnaire responders also indicated that an improved ability to intercommunicate with other agencies within Anoka County and with agencies outside the County is a very important need for improvement. 2.3 ANALYTICAL DETERMINATION OF RADIO COVERAGE The questionnaire results of both fire and law enforcement indicate that coverage needs to be improved. The questionnaire is an empirical method for determining deficiencies and needs for improvement. There are analytical methods that can also be used to determine coverage performance for comparison to the empirical data obtained from radio users. One of those analytical methods is actually measuring radio field strength during a drive in a vehicle throughout the County. A drive test was performed on the fire main county-wide dispatch channel and on the" two law enforcement main dispatch channels. Detailed maps of the actual field strength have been provided to Mr. John Tonding at Anoka County Central Communications. The next three pages of this report show the area in which coverage with a portable radio attached to a belt would be predicted in light industrial and commercial, as well as residential buildings. That area is within the line marked "-87 dBm Measured" on the maps. There is a fourth map that shows the area in which reliable radio page reception can be expected for a radio page receiver mounted on a belt inside light industrial, commercial buildings and residential buildings. That area is within the line marked "-77 dBm Measured" on the map. The field measurement maps on the next four pages are for light industrial, commercial buildings and residential buildings. Larger buildings such as schools, community complexes, hospitals and shopping centers would have spotty areas of coverage. Smaller industrial and commercial buildings that are metal skinned and/or have few or no windows would also have spotty or poor radio coverage performance with a portable radio worn on the belt indoors. In addition to the actual radio field measurements, computer predictions of coverage from the radio sites were also produced and they are also shown on the maps on the next four pages of this report. The computer predicted coverage 95% ofthe time to a portable radio carried on a belt is under the fan shaped pattern of radial lines. Computer predictions are not as accurate as the actual field measurement because there are variations which are treated county-wide on a statistical basis in the computer but are actual conditions when the field measurements are made. Nevertheless, the computer predictions are reasonably close to what was determined to be the actual conditions during field measurements. Ronald Vegemast Engineering, Inc. -10- Report: Anoka County