Voting Systems | |||
Voting systems are used where
walkies may be on the fringe of their ability to talk back to the repeater. A repeater is
typically 25, 50, or 75 watts; a walkie is typically 4 watts. The walkie can hear the
repeater much farther than it can talk back. Properly and strategically placed satellite receiver bays extend the useful range of walkies and insure perfect reception. Repeater transmitters can be placed at locations where they have the best range and penetration into buildings. Voting systems can be integrated with repeaters, or they can be integrated with stand-alone transmitters. Voting Receivers Voting systems utilize special receivers, called Satellite receivers; and Voting Comparators. Satellite receivers are connected back to a comparator at a central point by way of microwave links, phone lines, or voice circuits on T-1's. Voting systems can cover a large geographical area (county or area-wide), or they can be concentrated to provide absolutely solid portable communications in a small area (city-wide). |
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Each satellite receiver places a signal on the audio circuit which indicates that it is idle (no signal). The comparator senses that signal and is idle also. When a user transmits, he will hit several receivers at once on that channel. One of those receivers will have the best signal. The comparator chooses or "votes for" the receiver with the best signal quality and routes the audio to the transmitter. |
Temporary Receiver Bank Emplacement |
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Roof Of Dispatch location. The left path (black line) goes to the truck (above left) and the right path goes to a remote receiver location (above right) |
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Comparators The comparator looks at the audio from all the receivers and "votes" for the one with the best signal-to-noise ratio. The comparator sends a signal to the transmitter causing it to key up and then routes the receiver audio to the transmitter. The comparator continues to examine the signals from all the receivers during the transmission. If a different receiver begins to hear the user better than the original voted receiver, the comparator will switch to that receiver without interrupting the transmission. This switching between receivers may occur several times in a few seconds. When the system is properly set up, the switching is inaudible and transparent.
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Voting Repeaters Voting repeaters are different from normal repeaters in that their receivers are not directly connected to their transmitters. The receiver in a voting repeater is instead connected to a voting comparator along with the satellite receivers for that channel. In a voting repeater, the receiver which is being repeated by the transmitter may be 30 miles away from the transmitter. The voting repeater transmitter and the voting repeater receiver are connected back to the voting comparator via microwave circuits, phone lines, or by voice circuits on T-1's. In the event of a comparator failure or the loss of a microwave path, phone line, or T-1, our custom configured voting repeaters automatically sense the fault and revert to standalone normal repeater operation until connectivity is restored.
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Voting systems can also be linked so that they cross-vote. |