Simulcast - Charlotte UASI

[lcsunk]

Hi! Random question which I’m not sure how to even begin researching on my own.

Is it possible to know how many towers/repeaters are used in the Charlotte UASI region for the entire system? If it’s possible, how can I figure out?

This is purely a question out of curiosity. I’m trying to figure out how someone in the south of Charlotte could talk to someone in the north of Charlotte on the same radio channel. I’m new to this, but just find this so fascinating.

 

[IcomIcR20]

There are nine licensed sites for Mecklenburg Simulcast, seven for Union Simulcast, six for Cabarrus Simulcast, four for Gastonia Simulcast, five for Stanely Simulcast, and one in Mooresville. Of course, I cannot personally confirm that each and every one of said sites is actively in use.

You can click on each site listed in the database and see the corresponding licensed tower locations. For instance:

Charlotte UASI Site: Mecklenburg Simulcast

Charlotte UASI Site: Mecklenburg Simulcast Details

www.radioreference.com

 

[CLTscanner]

A simulcast system has multiple towers that are all broadcasting the same signal, on the same frequency, at the same time. The transmitters are synchronized so the signals do not interfere with one another. (Simulcast system alignment is a whole topic of itself.)
On the Receiver side of the system, when a radio keys-up, the system votes which tower has the best signal to rebroadcast across the system. This happens within a fraction of a second. Also voting is typically done based on Signal-to-Noise ratio, not just signal strength.

I’m trying to figure out how someone in the south of Charlotte could talk to someone in the north of Charlotte on the same radio channel.

So when a radio user in South Charlotte keys-up, they may hit the Tyvola tower for receive, but it will be rebroadcast across all towers. Then when the responding user in North Charlotte keys up, they may be hitting the North tower for receive, but then rebroadcast across all towers in the system.

It’s pretty fascinating stuff. And all of this takes place in the background without the radio users knowing the technical details. They just know that when they push PTT, the radio works across the county.

There are many places to read about this on the internet, but this is high-level what is happening.