EFIX FL3 UHF RTK Datalink Radio Modem

Reliable RTK radio communication for GNSS fieldwork

The EFIX FL3 is an external UHF radio modem designed to transmit RTK GNSS correction data between a base station and rover receivers. It is a practical choice for surveyors, construction crews, GIS teams, drone mapping operators and engineering companies working in areas where an independent radio link is preferred over mobile data.

In the field, a stable correction link is just as important as the GNSS receiver itself. The FL3 helps a base station send correction data across a project site so rovers can keep working with accurate RTK positions. This is especially useful for road construction, earthworks, land surveying, utilities, agriculture, open-pit sites and remote mapping jobs where cellular coverage can be weak or inconsistent.

Long-distance UHF correction transmission

The EFIX FL3 operates in the 410 MHz to 470 MHz UHF frequency range and is built for base-to-rover RTK communication. Under good field conditions, it can provide correction transmission over distances of up to 30 km or more, allowing one base setup to support a wider working area and, in many cases, multiple rover users.

For survey teams, this means fewer base relocations and a more efficient workflow across larger sites. For construction and machine control support teams, it helps keep crews connected to the same correction source while working across open fields, infrastructure corridors or large job sites.

Adjustable power for different site conditions

The FL3 offers adjustable transmit power up to 28 W. Lower power settings can be used when the rover is working close to the base, while higher power settings are useful for longer distances or more difficult radio environments. This flexibility helps balance communication range, power use and site requirements.

The radio supports common RTK datalink protocols including CHC, Transparent and TT450S, making it easier to integrate into different GNSS base and rover setups. It also supports selectable wireless link rates, so the radio can be configured to suit the correction format and project workflow.

Built for outdoor survey and construction sites

The EFIX FL3 has a robust metal housing with IP67 dust and water protection. This makes it suitable for daily outdoor use on construction sites, survey tripods, base station setups and temporary project installations. The housing also includes heat dissipation features to support stable operation during longer working sessions.

The unit uses a 5-pin LEMO port for external power and data transmission, a TNC antenna connection and an RS232 serial interface. These are familiar connection types for professional GNSS and survey equipment, making the FL3 a straightforward addition to many existing RTK base station kits.

Simple control in the field

The front panel includes a display, status indicators and control buttons for quick configuration. Operators can select channels, change data protocol, adjust link rate, set transmit power and check device status without needing a complicated setup process. This is helpful for crews that need to get a base station running quickly before starting measurements, stakeout or machine control support work.

The FL3 can work as a transceiver, transmit-only radio, receive-only radio or radio repeater. Repeater mode can be useful when a direct base-to-rover radio path is difficult due to distance, terrain or site obstructions. As with all UHF equipment, frequency and power use should always follow local radio regulations.

Who uses the EFIX FL3?

The EFIX FL3 is mainly used by professionals who need dependable RTK correction transmission in the field. Land surveyors can use it for topographic surveys, boundary work and stakeout. Construction teams can use it to support GNSS rovers on earthworks, road projects and site preparation. GIS and mapping crews can use it when collecting accurate field data away from reliable mobile networks. Drone mapping teams can also use a radio-based base setup when ground control and GNSS correction workflows require a local RTK link.

For buyers comparing GNSS radio equipment, the FL3 is best understood as a rugged external datalink for projects where range, stable correction delivery and practical field setup matter more than extra software features.

Buying from Global GPS Systems

Global GPS Systems supplies professional GNSS equipment for survey, construction, mapping, drone and GIS users worldwide. When adding the EFIX FL3 to a GNSS workflow, the team can help check compatibility with your receiver setup, antenna, cables and correction method so the radio is configured for the way your crew actually works in the field.