Garmin Introduces GDM 4500 and GDM 450R Remote-Mount DME Radios.

Now Compatible with TXi Flight Displays — Shipping Q3 2025

Garmin has launched two advanced Distance Measuring Equipment (DME) systems — the GDM 4500 and GDM 450R — bringing high-accuracy, remote-mount DME capabilities to a broad range of aircraft, including general aviation, turbine platforms, and rotorcraft.

These digital DME radios are engineered for seamless integration with Garmin TXi™ flight displays, integrated flight decks, and select third-party systems. They provide precise slant-range distance measurements to DME ground stations and introduce support for multi-channel operation, DME-DME RNAV, and automated scanning.

Technical Highlights and Capabilities

GDM 450R — For Part 23 General Aviation Aircraft

- Dual-frequency tuning: Supports two active DME channels simultaneously via NAV radios
- DME Hold Function: Maintains slant-range distance even when NAV frequency changes
- Multi-channel scanning (optional): Enables up to three additional DME frequencies for RNAV
- Free Scan capability: Automatically searches and identifies nearby DME stations
- Legacy compatibility: Supports legacy databus connections for older indicators and radios
- Compatible with Garmin TXi Displays and integrated flight decks

GDM 4500 — For Turbine Aircraft & Rotorcraft

- Meets enhanced environmental qualifications for high-performance operations
- ARINC 429 compatibility enables integration with select third-party avionics
- DME-DME RNAV and Free Scan support standard (via compatible FMS)
- Connects to TXi and Garmin integrated systems with advanced interface capabilities

System Integration & Upgrade Path

- Compatible with upcoming TXi software update, which allows direct HSDB connection (no GAD 43e required)
- Future updates for GTN Xi Navigators and TXi Displays will enable advanced multi-channel DME functions.
- Requires an L-band DME antenna (sold separately)
- Expected availability: Shipping begins July 16, 2025 (Q3)

Operational Benefits

- Enhances navigation redundancy and accuracy via DME-DME RNAV
- Reduces panel clutter and simplifies installation with remote-mount architecture
- Maintains compliance with regional airspace requirements where DME is still mandated
- Provides a cost-effective upgrade path for ageing DME systems in both GA and turbine-class aircraft

Have questions about system compatibility or integration?