How Simulcast works — greater coverage with fewer frequencies

Radio Communication TowerSimulcast (simultaneous broadcasting) means multiple base stations transmitting the same voice (or data) signal on the same frequency at the same time. This means that every frequency pair – probably your existing channels – can each provide greatly extended coverage across a very wide area. The secret to Simulcast is high-stability transmitters and signal timing, structured and implemented by coverage experts to negate potential interference.

To understand how Simulcast works, let’s look at some simple simulcast networks:

A simple Simulcast network

Two sites provide coverage across a wide geographical area. Each site has a single base station set to the identical frequency pair.

Two sites, one channel

Two sites, one channel

Wherever your first responders travel, throughout the coverage area, their mobile and portable radios can all transmit and receive on the same channel. Effectively, the two sites operate as a single site, dramatically increasing the channel’s coverage over a much wider area.

Adding more traffic capacity for more conversations

It’s easy to accommodate more conversations, simply by adding another frequency pair (channel) at both of your sites.

Two sites, two channels

Two sites, two channels

Network design for traffic density variation

If your traffic density differs across your coverage area, you may only need additional frequency pairs (channels) at one site.

Two sites, one channel at one site, three at the other

Two sites, one channel at one site, three at the other

Add more channels in your urban areas, based on your predicted traffic. There is no need to replicate every frequency at every site.

Scaling up to a larger network

Using these examples, it is a simple matter to scale up your network according to your current needs. Then, as your traffic patterns and coverage needs change or increase over time, new frequencies are added precisely where they are needed.

More sites, more channels as and where you need them

More sites, more channels as and where you need them

How Simulcast moves beyond weak signals, coverage black spots and interference

Expert network design, coverage modelling and configuration are the keys to managing interference and dealing with coverage black spots. You’ll need to ensure that your supplier fully understands your agency’s coverage priorities and requirements.

Using exact timing signal intelligence from the GPS receivers at each site, transmitters can transmit simultaneously. At any position within the coverage area, one signal will be stronger than the others, and can capture the receiver, so that other signals have no effect.

Your intelligence-based network can be easily upgraded by simply reconfiguring the transmitter timing signals to accommodate your new requirements. This should take into account recent coverage influences such as new buildings erected or forests growing.

Learn more about TaitNet P25 Digital Simulcast: Easy to use with built-in intelligence.


  1. John Sakowich says:

    I am trying to understand this process. Your article says everyone can talk at the same time on the same channel.
    Then your talking about having frequency pairs. Well if everyone is talking and listening on the same channel what do you mean you have frequency pairs? Then adding more frequency pairs for more coverage. Here again everyone is on one frequency but your talking about frequency pairs. So if you could please explain this to me so I may understand this better

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