A robot mower reporting no loop signal or a lost satellite fix has lost the reference it uses to know where it is: on boundary-wire models that means a broken loop, a dead base station, or a loose connection, and on wire-free RTK models it means the antenna or mower cannot see enough satellites.
Wire-based (loop signal) causes
- Broken or cut boundary wire. A single break anywhere in the loop stops the signal around the entire perimeter. Cuts come from digging, edging tools, frost heave, and rodents.
- No power to the base station. A tripped outlet or unplugged supply leaves the loop with nothing to energize it, so the mower reads no signal even with the wire intact.
- Loose wire terminals. The loop ends can back out of the base station connectors, especially after weather or vibration.
- Interference. Nearby buried cables, metal, or another mower’s loop can disturb the signal near certain sections.
Wire-free (satellite) causes
- Blocked sky view. The reference antenna or the mower under dense tree canopy, next to tall buildings, or beside a solid fence cannot lock onto enough satellites.
- Reference station moved or unpowered. The fixed antenna needs a stable, powered, open-sky position. If it was moved or lost power, the mower loses its correction.
- Connection dropout. RTK systems rely on a data link between the reference and the mower. A weak link in far corners breaks the precise fix.
Fixes to try in order
- Confirm the base station has power. Check the outlet and the supply indicator. Restore power and watch whether the signal light returns to a steady state.
- Reseat the loop connections. On wire systems, open the base station and make sure both loop ends are firmly seated in the correct terminals.
- Find and repair a wire break. Walk the perimeter for disturbed ground and visible damage. Many models signal a break with a specific indicator pattern, so check the base station lights against the manual. Splice cleanly with a waterproof connector.
- Clear the sky view. On RTK systems, confirm the reference antenna sits in the open, is powered, and has not shifted. Trim overhanging branches and move the antenna away from walls and metal.
- Re-check corners and far zones. If the fix drops only in certain areas, the problem is local: a wire section near interference, or a spot where satellite coverage or the data link is weak.
- Restart the system. Power the base and the mower off and on so both re-establish the signal or satellite fix from a clean state.
When it is the mower, not the lawn
If the base is powered, the loop tests continuous, or the antenna has clear sky and the mower still cannot hold a signal, the fault may be internal. A failing signal receiver, a damaged antenna on the mower, a worn wheel motor that strands it outside coverage, or a firmware regression that changed how the mower reacquires its fix after an update can each produce a persistent no-signal state. Note whether the error appeared right after a firmware update, since that points to software rather than hardware. Follow model-specific reports and update notes on the Tracker, and see our overview of robot mower autonomy.