Compass-stabilising a Furuno radar with a fluxgate compass

[Babylon]

I'm about to fit a stand-alone radar (a Furuno 1623). Although by itself it will work in Heading mode, in order to be able to use the radar in North-Up mode (ie 'compass-stabilised), it needs to be interfaced with a fluxgate compass. 2 questions:

1. Can this Furuno be set up to work in North-Up mode? Nothing in the sales literature alludes to it, so maybe peeps who have or have used this radar can help?

2. Assuming it can be, how is this actually achieved? Does one just go out and buy a stand-alone fluxgate compass and stick it somewhere, or is there some fangled way of interfacing it with the fluxgate compass in say the autohelm?

Thanks, as ever, in advance

 

[Boathook]

It might work north up when connected to a gps. You will have to be moving though for it to possibly work.

 

[earlybird]

The 1623 cannot be set to display north up, only head up.
If you supply NMEA heading data from a suitable compass, ie sentences HDG or HDM, the EBL on the display can show true heading of a target. GPS input will also enable this if the boat is moving.
Additionally, the HDG or HDM will allow you to plot target position on, say, a Yeoman plotter as described in the manual. GPS input does not enable this.

 

[Babylon]

Is being limited to head-up display a major disadvantage?

The 1623 cannot be set to display north up, only head up.
If you supply NMEA heading data from a suitable compass, ie sentences HDG or HDM, the EBL on the display can show true heading of a target. GPS input will also enable this if the boat is moving.
Additionally, the HDG or HDM will allow you to plot target position on, say, a Yeoman plotter as described in the manual. GPS input does not enable this.

Thanks for this Earlybird

I have a Yeoman plotter, so that's good to know.

Have recently done a radar course and have been reading further to explore its full potential. My main concern of course is collision-avoidance in fog, where working out the CPA in head-up mode seems quite straightforward. But, to use radar for coastal 'pilotage' I understand that working in North-up mode (which also stabilises the display) makes working everything out a little less head-bending - but I assume can be done in head-up mode with a little practice?

The alternative is to fit a more sophisticated system (Raymarine?), but the whole thing is getting pretty expensive as it is.

 

[st599]

I'm about to fit a stand-alone radar (a Furuno 1623). Although by itself it will work in Heading mode, in order to be able to use the radar in North-Up mode (ie 'compass-stabilised), it needs to be interfaced with a fluxgate compass. 2 questions:

1. Can this Furuno be set up to work in North-Up mode? Nothing in the sales literature alludes to it, so maybe peeps who have or have used this radar can help?

2. Assuming it can be, how is this actually achieved? Does one just go out and buy a stand-alone fluxgate compass and stick it somewhere, or is there some fangled way of interfacing it with the fluxgate compass in say the autohelm?

Thanks, as ever, in advance

No - you need a compass to achieve azimuth stability. Imagine your boat is yawing about due to waves by say 15 degrees.

Scanner rotates and target A is at 60 degrees, bat yaws as scanner rotates and by the time it picks up that target again it's at 75 degrees. You see two different targets.

The RADAR processor uses the heading information to stabilise to an average heading. This also allows the processor to display North Up - but that's not the primary reason.

 

[st599]

Thanks for this Earlybird

I have a Yeoman plotter, so that's good to know.

Have recently done a radar course and have been reading further to explore its full potential. My main concern of course is collision-avoidance in fog, where working out the CPA in head-up mode seems quite straightforward. But, to use radar for coastal 'pilotage' I understand that working in North-up mode (which also stabilises the display) makes working everything out a little less head-bending - but I assume can be done in head-up mode with a little practice?

The alternative is to fit a more sophisticated system (Raymarine?), but the whole thing is getting pretty expensive as it is.

Why would you do CPA in anything but North-up? It's much simpler, and the only way institutions like the RN and the RNLI allow it to be done.

 

[Babylon]

Why would you do CPA in anything but North-up? It's much simpler, and the only way institutions like the RN and the RNLI allow it to be done.

Thanks. This is the whole reason for my original question. I was all set to buy a Furuno 1621, but as I've found out it can only be used in course-up mode, then this lack of 'functionality' means it becomes a false economy, and I should look for a (used) Raymarine unit instead which can operate in North-up mode.

 

[earlybird]

Thanks. This is the whole reason for my original question. I was all set to buy a Furuno 1621, but as I've found out it can only be used in course-up mode, then this lack of 'functionality' means it becomes a false economy, and I should look for a (used) Raymarine unit instead which can operate in North-up mode.

A bit picky, but the 1623 operates in head-up mode, not course up, which is slightly different.
However, my main reason for this post is my belief that, for accurate CPA purposes, a radar really needs rather better and faster heading info than that provided by the average fluxgate compass. This comes at some cost.
This view is based on what I have read, rather than direct experience, so someone else might know better!