Radar Hate`

[KREW2]

I have just put a new GPS antenna on my Ray C80 chart plotter. Unfortunately the auto helm ST4000+ kept giving a seatalk failure message.
I solved this problem by disconnecting the seatalk plug at the back of the plotter. This means I now have a stand alone C80 that does not link to seatalk, and that is fine by me

The plotter gets good satellite coverage works fine, and displays both boat and cursor position. The problem comes when I select the radar page. The radar scans and works okay and the boat position is displayed, but there is no cursor position shown.

I am wondering if it is because it is not getting a heading via seatalk from the autohelm. I'm led to understand that with no heading I will not be able to use the MARPA function. If this is the case is there a solution?

 

[PilotWolf]

Can't remember about MARPA but 'proper' ARPA requires it.

W.

 

[jdc]

The Raymarine manual says:

4.16 Fastheading connection
If you wish to use MARPA (radar target acquisition) functions on your multifunction display you need either:

• An autopilot connected to the multifunction display via SeaTalk ng or NMEA 0183. The compass is connected to the course computer and calibrated via the pilot control head; or:
• A Raymarine or third-party fastheading sensor connected to the multifunction display via NMEA 0183.

The solution seems to be to fix the attachment of the autopilot to the C80 (Bullet point one above).

You didn't solve the problem by disconnecting it, you just shelved investigating what was wrong (as in 'I solved my car's breakdown by walking home...'). I think it would be worth trouble-shooting why the autopilot complains: fix that and there's every chance the MARPA would would spring into life. In the other direction, the connection between MFD and autopilot can also be useful as it allows the pilot to steer to waypoint rather than merely compass course, which can be quite useful in strong but erratic cross tides.
Edit: my plotter needs a converter from Seatalk to Seatalk_ng, as shown below. It has peculiarities with power leads which could also be the case with yours?

 

[Neeves]

Don't you have an independent fluxgate compass?

Jonathan

 

[KREW2]

JDC
Thanks for your input.
I don't think problem was with the autohelm ST4000+ the problem is the new antenna, it wires directly into the C80, not the seatalk loop, and cannot input data to the autohelm via seatalk, only nmea hence the fail message.
The old antenna is one of these https://www.manualsdir.com/manuals/200465/raymarine-raystar-125.htmlwhich is now obsolete.
I think I need to get heading data via nmea not seatalk into the plotter, I don't know if that is possible without getting a new independent heading sensor.
My other alternative is to try changing the small battery in the old antenna, if that works then I can reconnect the seatalk cable. Unfortunately it will involve removing a lot of bits and pieces and headlining.

 

[KREW2]

Don't you have an independent fluxgate compass?

Jonathan
[/QUOTE

I think the only fluxgate compass is connected into the seatalk loop.

 

[jdc]

Can't the C80 be programmed to output GPS sentences on the Seatalk interface even if it is receiving them from an external source? There's also the Bridge NMEA Heading option to consider.

 

[KREW2]

Thanks again,
I will pop down today and try.
.

 

[KREW2]

Bridge setting did not solve it. I decided to remove the old antenna, replace the small lithium battery in it, reconnect the old nmea cables and Seatalk all now seems good.
thanks again