# RTK radio data link

Use a radio data link if you are sending or receiveing RTK data from a radio at the base receiver over a radio channel.

Configure the connection to the radio at the rover or at the base using the data link screen in the survey style. See To configure a rover radio data link or To configure a base radio data link.

To start the survey, see To start an RTK radio survey at the rover.

Radio considerations

Real‑time survey methods rely on trouble‑free radio transmission.

To reduce the effects of interference from other base stations operating on the same frequency, use a transmission delay for your base station that does not coincide with others on the same frequency. For more information, see Operating several base stations on one radio frequency.

Sometimes the conditions or topography of a site adversely affect radio transmission, resulting in limited coverage.

To increase site coverage:

- Move the base stations to prominent points around the site.
- Erect the base radio antenna as high as possible.
- Use radio repeaters.

Double the height of the broadcast antenna to increase the coverage by approximately 40 %. To achieve the same effect, it would be necessary to quadruple the radio broadcast power.

Radio repeaters

Radio repeaters increase the broadcast range of a base radio by receiving the base transmission and then rebroadcasting it on the same frequency.

You can use one repeater with a radio that has a 12.5 kHz channel spacing, and one or two repeaters with a radio that has a 25 kHz channel spacing.

You can configure the internal radio in a Trimble GNSS receiver to repeat base data to other rovers while performing a rover survey. This is known as a roving repeater setup. The internal radio can repeat the base signal over its UHF communication link to other rovers while simultaneously performing a rover survey. This option is available in Trimble GNSS receivers with internal radios that have the UHF Transmit option enabled. Select this repeater mode when you connect to the internal radio from the Rover data link screen in the survey style.

To use any of these radios as repeaters, they must be configured as repeaters. To do this, follow the steps above to connect to the radio and then choose a repeater mode, which appears if the radio you are connected to supports being a repeater. Alternatively, if the radio has a front panel, use that to set the repeater mode.