Talkgroups are virtual channels used on a trunked radio system. Instead of using fixed frequencies, radios join a Talkgroup ID (TGID) that represents a specific group of users, such as police dispatch, fire operations, or public works.

Use this page to search for and explore radio calls by Talkgroup ID. This helps you understand what type of activity is happening and which agencies or functions a call belongs to. Busy talkgroups often indicate primary dispatch or tactical use, while rarely used talkgroups may be special events, mutual aid, or administrative channels.

Every radio on a trunked system has a unique Radio ID (RID). This identifies an individual portable radio, mobile radio, or dispatch console rather than a group.

Use this page to search for calls made by a specific radio. This is useful for identifying individual units, tracking activity patterns, or distinguishing between field units and dispatch consoles. Over time, you may recognize which Radio IDs belong to supervisors, apparatus, or fixed control stations.

Sites are the physical transmitter locations that make up a trunked radio system. Each site covers a geographic area and is identified by an RF Subsystem (RFSS), Site Number, and Network Access Code (NAC).

This page shows which sites are carrying traffic, what talkgroups appear on them, and how radios move between sites. Understanding sites helps explain why certain calls are heard in one area but not another, and how wide-area systems provide coverage across cities, counties, or regions.

Trunked systems use a control channel to manage traffic and dynamically assign voice channels. Radios do not stay on one frequency; instead, they are directed to available channels as calls occur.

Use this page to view control channels, voice channels, and their Logical Channel Numbers (LCNs). This information shows how the system efficiently shares frequencies, which channels are most active, and how calls are distributed across the radio network.

The bandplan defines how logical channel numbers (LCNs) translate into real radio frequencies. It tells radios what frequency to tune when the system assigns a channel, and how that channel is structured.

In P25 Phase 2 systems, channels use TDMA (Time Division Multiple Access), where a single 12.5 kHz frequency is split into two time slots (Slot 1 and Slot 2). This allows two simultaneous voice calls on the same frequency. This page shows the system’s frequency ranges, channel spacing, offsets, number of time slots, and whether traffic is FDMA (Phase 1) or TDMA (Phase 2). Understanding the bandplan and slot usage is essential for properly decoding calls and interpreting how capacity is shared across the system.

Patch groups show temporary relationships where multiple talkgroups are bridged together by the radio system.

Talker aliases are radio-provided labels observed on the control channel. They are shown separately from curated RadioResolve radio labels.

This page shows when SDRTrunk-reported RF infrastructure changed, including new sites, channel changes, neighbor changes, bandplan changes, patch groups, and talker aliases.