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11 If the direction for delivering improvement to public safety land mobile radio systems in Anoka County follows the path of enhancement of existing systems, a relatively small number of circuits, five or less, will be required on each link. If an 800 MHz trunked radio alternative is selected, a minimum of 13 circuits will be required on each link. From a pure cost perspective, microwave radio could not be justified if enhancement of the existing radio systems is the direction selected. There would be a reasonable payback period for the microwave links if an 800 MHz trunked radio system alternative is selected assuming that the regional 800 MHz radio system microwave network currently being constructed can be used as a backbone and only spur microwave links would need to be added. The reliability of microwave is generally far better than the reliability of leased telephone facilities. Microwave circuits tend to be quite stable while telephone circuits are often unstable due to many factors including the moisture level surrounding lines and other facilities. Audio clarity of microwave is excellent while audio clarity on telephone lines is often negatively impacted by noise caused by many factors. Microwave can be cost justified if an 800 MHz trunked radio system alternative is the direction selected to provide improvements to the land mobile radio system. In addition, microwave will provide a greater level ofreliability and better quality circuits. Use of microwave cannot be cost justified if the direction selected for improving public safety land mobile radio systems in Anoka County is to enhance existing systems. Use of microwave, if existing systems are to be enhanced, will likely provide a higher level of communications link reliability and quality, but at a higher cost than use of telephone lines. It is recommended that the backbone microwave network currently under construction for the regional 800 MHz radio system be used provided the Metropolitan Radio Board grants permission for that use. Additional hot-standby point-to-point links from that regional backbone microwave to remote radio sites should be selected regardless of the direction decided upon for improving land mobile radio systems in Anoka County if the additional cost can be justified. In the event that enhancing the existing systems is the direction selected to improve the land mobile radio system, and the additional cost of the microwave links cannot be funded, then it is recommended that all stations be controlled through in-band tone signalling over regular telephone lines. This will mean that all DC continuous lines will have to be eliminated. Ronald Vegemast Engineering, Inc. -32- Report: Anoka County