Radar calibration

[efanost]

Hello clever people,

I switched on, for the first time on my new-to-me boat, the radar. I noticed that there is a huge offset between the radar overlayed image, and the chart and AIS targets.

If you see the picture attached, the radar image seems consistently off the charted coastline, the charted wind turbines and the AIS target.

Should I just need to go and read the manual to figure out how to re-calibrate my radar? Maybe that's the simple answer, but I'd be surprised that the previous owner has not done anything about it. Or could it be something else that affects the accuracy of the overlay?

Thanks!

[Kelkara]

Somewhere if you drill down deep enough into the menus there will be a setting to adjust the angle of the radar.

This will fix your problem ... but it may only be a temporary fix.

The problem may not be with the radar at all ... I had a very similar problem ... I eventually discovered it was the heading sensor that needed recalibration (on my boat that was best done by a full reset on the autopilot).

[CrispyCringle]

Looking at the photos, it appears that the radar range is okay. You just need to adjust the radar heading. If you rotated the radar image layer in those pics counter clockwise I think it would matchup with the coastline. Its an easy fix, but you have to dig into the menus and (gasp) the manual. Looks like it needs about a -10 deg correction.

[requiem]

Originally Posted by Kelkara

The problem may not be with the radar at all ... I had a very similar problem ... I eventually discovered it was the heading sensor that needed recalibration (on my boat that was best done by a full reset on the autopilot).

Agree, it would make sense to determine which of the two is correct before making one match the other. You could check the radar by checking returns of something dead-ahead, and similarly check the heading sensor against an object of known bearing, e.g. Polaris. (Don't trust your ship's compass until you've similarly verified it.)

[Lodesman]

Where's ownship heading info coming from - fluxgate compass?
If radar heading is magnetic and chart displayed in true, the angular difference is simply variation. It might be as simple as displaying chart in mag.

[Ryban]

If heading info isn't coming from a digital compass input, then it's coming from a GPS derived heading, which may be fluctuating.

[capt jgw]

Back in the days before MFD's (and on the old radar I'm still using), the method was to head straight at a stationary target you could see visually and see where it appeared on the radar display. Then accessing calibration mode put the EBL on the radar target and using the knob swing it to 000 deg. All while maintaining course dead at the target. It's easier with two people, one on the helm and the other tweaking the radar. If you do that and it's still offset, you will know the problem is not radar calibration, it's something else. I wouldn't expect the radar and chart display to align perfectly 100% of the time, there are variables. But if you have a visual target dead on your bow, the radar should show it at 000 relative, 100% of the time.