Difference between revisions of "Simulcast"
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− | '''Simulcast''' refers to the process of transmitting the same signal from '' | + | '''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 | + | 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, | + | 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) | ||
[[Category:RR Glossary]] | [[Category:RR Glossary]] |
Revision as of 16:17, 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)