Short Answer
A DMR repeater receives a radio signal on one frequency and retransmits it on a second frequency. This allows larger areas, buildings, or challenging terrains to be covered. Typically, two time slots are available in DMR Tier II, allowing for two separate communication paths on a pair of channels. Planning, location, antenna, duplexer, power supply, and frequency allocation are crucial.
DMR repeaters are a central component of many professional operational radio networks. However, they do not automatically solve every range issue.
How a DMR Repeater Works
| Element | Task |
|---|---|
| Receiving Frequency | Receives signals from the radios. |
| Transmitting Frequency | Re-transmits the signal from a better location. |
| Duplexer | Separates sending and receiving at one antenna. |
| Time Slots | Enable two logical paths in DMR. |
| Antenna | Significantly determines the actual radio coverage. |
What Needs to be Planned
- Frequencies and concessions.
- Repeater location, antenna height, and lightning protection.
- Duplexer, filters, cable losses, and power supply.
- Call groups, time slots, and emergency call logic.
- Measurement, documentation, and maintenance.
Typical Errors
The repeater is installed at an unsuitable location, without measurement and without a properly tuned antenna system. Incorrect duplexers, high cable losses, and unclear time slot allocation are also critical.
FAQ
When do you need a DMR repeater?
When direct radio does not reliably achieve the necessary range or building penetration.
Why does DMR have two time slots?
DMR utilizes TDMA. This allows for two logical voice or data paths to occur on a pair of channels.
Can a repeater always solve dead spots?
No. Location, antennas, building structure, and interferences must be suitable.
Does a repeater require a permit?
For professional operational radio in Switzerland, frequency usage must be clarified properly.
Sources and Currency
This page was created on July 6, 2026. Technical and regulatory information must be compared with current manufacturer data, standards, frequency specifications, and location conditions for specific projects.