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Difference between revisions of "Simulcast"

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'''Simulcast''' refers to the process of transmitting the same signal from ''multiple sites'' on ''the same frequency'' at ''the same time''.   
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'''Simulcast''' refers to the process of transmitting the same signal from ''different tower locations'' over ''the same frequency'' at ''the same time''.   
  
For public safety communications, this typically means multiple towers configured to transmit the exact same communications, on the exact same frequencies, at precisely the same time, resulting in much better coverage of a wide area or area with dense population/buildings.  Such systems must use some form of very precise timing to synchronize their multiple transmitters, or interference can result from mis-timed signals destructively mixing in a subscriber radio's receiver.
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For public safety communications, this typically means multiple towers: configured to transmit the exact same communications, on the exact same frequencies, at precisely the same time. Which can result in better coverage of a wide-area or a dense area with higher populous and/or buildings.  Such Simucast Systems (Sites) must use some form of very precise timing: to synchronize, their, multiple transmiting tower sites, or interference can result, from mis-timed (asynchronise) signals, destructively mixing, in a receiver i.e. scanner or even a subscriber's radio on that system.
  
Simulcast is not analogous to multiple site wide area networked trunking systems that use different frequencies at each site, however simulcast "cells" (several sites operating as one in a simulcast configuration) can be implemented in such systems.
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Simulcast is not analogous to multiple-site wide-area-networked trunking systems, that use ''different frequencies'', at each site; however, simulcast "cells" (several sites operating as one in a simulcast configuration) can be implemented in such systems.
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Example:
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Washington County (example only) Has 4 Sites: north, east, west, south; each is listed as a "Simulcast Site" in the RRDB.  These Sites cover their intended area with frequencies that differ amoungst each site, but share all "Commom" Talkgroups.  Generally each site carries its own traffic on the individual Sites, without a Dispatchers "Console" interference, in extreme circumstances the Dispatchers Console can enable all 4 Sites to "All talk", cross-linking together; now some may argue that this is the only time the Washington County is truely "Simulcast" but henceforth it's just "A System" with 4 independent ''Sites''.  These 4 Sites allow 4x the amount of traffic to be on the Washington County Public Safety System at any given time.
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North
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852.2625
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851.6500
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East
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852.9000
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856.2125
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West
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852.6825
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851.7125
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South
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851.3500
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853.7000
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In reality:
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North actually has 4 Tower locations (1 Simulcast Site)
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East actually has 6 Tower locations (1 Simulcast Site)
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West has 3 Tower Locations (1 Simulcast Site)
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South has 5 Tower Locations (1 Simulcast Site)
  
 
[[Category:RR Glossary]]
 
[[Category:RR Glossary]]

Revision as of 11:17, 27 April 2016

Simulcast refers to the process of transmitting the same signal from different tower locations over the same frequency at the same time.

For public safety communications, this typically means multiple towers: configured to transmit the exact same communications, on the exact same frequencies, at precisely the same time. Which can result in better coverage of a wide-area or a dense area with higher populous and/or buildings. Such Simucast Systems (Sites) must use some form of very precise timing: to synchronize, their, multiple transmiting tower sites, or interference can result, from mis-timed (asynchronise) signals, destructively mixing, in a receiver i.e. scanner or even a subscriber's radio on that system.

Simulcast is not analogous to multiple-site wide-area-networked trunking systems, that use different frequencies, at each site; however, simulcast "cells" (several sites operating as one in a simulcast configuration) can be implemented in such systems.

Example: Washington County (example only) Has 4 Sites: north, east, west, south; each is listed as a "Simulcast Site" in the RRDB. These Sites cover their intended area with frequencies that differ amoungst each site, but share all "Commom" Talkgroups. Generally each site carries its own traffic on the individual Sites, without a Dispatchers "Console" interference, in extreme circumstances the Dispatchers Console can enable all 4 Sites to "All talk", cross-linking together; now some may argue that this is the only time the Washington County is truely "Simulcast" but henceforth it's just "A System" with 4 independent Sites. These 4 Sites allow 4x the amount of traffic to be on the Washington County Public Safety System at any given time.

North

852.2625

851.6500

East

852.9000

856.2125

West

852.6825

851.7125

South

851.3500

853.7000

In reality:

North actually has 4 Tower locations (1 Simulcast Site)

East actually has 6 Tower locations (1 Simulcast Site)

West has 3 Tower Locations (1 Simulcast Site)

South has 5 Tower Locations (1 Simulcast Site)