Lowrance HDS Broadband Radar No Signal — Halo Fix

What Does This Error Mean?

Lowrance 'No Radar Signal' means the chartplotter can't communicate with the radar dome on the Ethernet network.
Causes: dome power off, network cable loose at switch or dome, dome firmware mismatch with chartplotter, or dome motor stuck.
Confirm dome has power, reseat the network cable at both ends, and check that both devices have compatible firmware versions installed.

Affected Models

Lowrance HDS Live
Lowrance HDS Pro
Lowrance HDS Carbon
Lowrance Elite FS with Halo

Common Causes

Radar dome powered off (separate breaker)
Ethernet network cable loose
Network switch failed or fuse blown
Firmware mismatch between dome and chartplotter
Radar dome motor stuck (failed to reach standby)
Radar processor inside dome failed

How to Fix It

Confirm dome power.

Most installs have a dedicated breaker for the radar.
Switch on, listen for the 'whoosh' as the dome motor spins up.
No spin = no power.
Check fuse on the dome power feed.
Reseat Ethernet cable.

Power off the network switch.
Unplug the dome's Ethernet cable at both ends — at the switch and at the dome (in the dome boot, requires opening cover).
Look at connector pins for green corrosion.
Push back firmly until you feel the latch click.
Power on switch, wait 60 seconds, power on dome.
Check network switch.

Lowrance NEP-2 or generic network switch should have lights showing each connected port.
If dome's port shows no light, that port is dead or cable is bad.
Try moving cable to a different switch port.
Confirm switch power LED is lit (check inline fuse if dark).
Verify firmware compatibility.

On chartplotter: Settings → System → About.
Note firmware version.
Compare with Lowrance website for radar compatibility — older HDS Carbon may need 17.x firmware to run new Halo20+ domes.
Update both to latest stable.
Listen for dome motor.

After power-on, dome should make a steady whirring sound.
Silence or grinding = motor stuck or failed.
Mechanical failure inside the dome is dealer service.
Replacement domes are 1500-3500 USD.
Power-cycle in correct order.

Power off chartplotter and dome.
Wait 30 seconds.
Power on the network switch first, then chartplotter, then dome last.
Order matters — the network must be up before either end-device tries to talk on it.

Frequently Asked Questions

Will the chartplotter work without the radar?

Yes — chart, sonar, GPS, and all other features still work.
Only radar functions are unavailable until the dome reconnects.
You'll see 'No Radar Signal' on the radar page; switch to chart or sonar pages and continue using the unit normally.