DMR Tier 1 & 2 is an open standard designed for professional, novice, and amateur communication. It operates using TDMA (Time Division Multiple Access), allowing two independent voice or data paths in a single 12.5 kHz channel. DMR has multiple tiers. Each serving different types of users. Tier 1 and Tier 2 are the most common, especially among amateur radio operators and commercial users.
DMR Tier 1 is intended for license-free use in specific frequency ranges, mainly in Europe. It uses lower power levels and is designed for short-range communication. In contrast, DMR Tier 2 is for licensed operation in VHF and UHF bands, supporting wider coverage and more advanced features.
How DMR Tier 1 Works
DMR Tier 1 operates in the 446 MHz band (PMR446 in Europe) using digital voice with TDMA. It offers two voice channels in a single 12.5 kHz bandwidth, providing efficient spectrum use. While radios in Tier 1 typically have limited output power, around 0.5 watts. This is intended for personal, recreational, or small business use without a license.
These radios communicate directly with each other in simplex mode. Since Tier 1 does not use repeaters, its range is restricted to line-of-sight distances. Its often between a few hundred meters to a couple of kilometers depending on terrain and building density.
How DMR Tier 2 Works
DMR Tier 2 is a licensed service designed for professional and amateur users who need greater range and flexibility. It operates on VHF (136–174 MHz) and UHF (400–470 MHz) bands, using repeaters to extend coverage far beyond line-of-sight. Tier 2 supports both voice and data, allowing features like text messaging, GPS tracking, and remote control of devices.
Because it uses the same TDMA structure as Tier 1, Tier 2 also provides two time slots per channel. However, these time slots can be used for separate calls, group communications, or data transmission. This makes Tier 2 suitable for public safety, industry, transportation, and amateur radio networks.
Differences Between Tier 1 and Tier 2
The most obvious difference is licensing. Tier 1 is license-free and limited to low power in specific bands, while Tier 2 requires a license and allows higher power and repeater use. Tier 1 is restricted to short-range, direct communication, but Tier 2 can cover entire cities or even larger areas when linked via networks.
Additionally, Tier 2 radios typically have more advanced features, including encryption, roaming, wide-area networking, and interoperability with multi-site systems. Tier 1 radios, on the other hand, focus on simplicity and affordability.
Advantages and Disadvantages of DMR Tier 1
Advantages:
- No license required in designated regions
- Simple operation with minimal setup
- Affordable equipment cost
- Two time slots in one frequency for efficient use
Disadvantages:
- Limited power and range
- No repeater capability
- Restricted to 446 MHz band in Europe
- Fewer advanced features compared to Tier 2
Advantages and Disadvantages of DMR Tier 2
Advantages:
- Higher power for greater range
- Supports repeaters and networks for wide coverage
- Advanced voice and data features
- Works in multiple VHF and UHF bands
- Suitable for professional, public safety, and amateur networks
Disadvantages:
- Requires a license to operate
- Equipment cost is higher
- More complex programming and setup
- May require infrastructure investment for repeaters
Specifications for DMR Tier 1
- Frequency Band: 446 MHz (PMR446)
- Channel Spacing: 12.5 kHz
- Modulation: 4FSK TDMA
- Time Slots: 2 per channel
- Power Output: Up to 0.5 watts ERP
- Mode: Direct/simplex only
- License Requirement: None (in designated regions)
Specifications for DMR Tier 2
- Frequency Bands: 136–174 MHz (VHF), 400–470 MHz (UHF)
- Channel Spacing: 12.5 kHz
- Modulation: 4FSK TDMA
- Time Slots: 2 per channel
- Power Output: Up to 50 watts depending on license class
- Mode: Simplex, repeater, or networked operation
- License Requirement: Yes
Other Pertinent Information
Both Tier 1 and Tier 2 use the same AMBE+2 vocoder for voice compression, which ensures consistent audio quality across devices. However, Tier 2’s ability to integrate with internet-linked systems like BrandMeister or TGIF makes it especially popular in the amateur radio community.
Because DMR is an open standard, many manufacturers produce compatible radios, leading to a wide variety of models and price ranges. Interoperability, though generally good, can still vary based on firmware and programming choices, so careful setup is important for mixed-brand systems.
Final Thoughts on DMR Tier 1 & 2
DMR Tier 1 & 2 each serve their own purpose. Tier 1 offers a simple, license-free entry point for short-range digital communication, while Tier 2 provides the power, coverage, and features needed for professional and serious amateur use. By understanding the differences, operators can choose the right tier for their communication needs and make the most of DMR’s efficient digital technology.