[TG] [TG11] No GPS Info on MFD GPS Status Page

[Tom - Raymarine - Moderator]

Hello magic8,

Re. power supply: a multimeter won't tell you truly what's happening, to really verify the supply it needs to be tested with an oscilloscope at a time when the GPS is indicating a problem - just something to bear in mind if there are further issues. I've seen supplies that looked ok on my multimeter that were anything from 9V to >100V extremes on an oscilloscope.

Have you turned Differential off, as described in the FAQ and mentioned previously? This is known to cause intermittent loss of fix in Australia.

Tom

[magic8]

Yes DGPS checked off
Will get to put further test gear on voltage as suggested
Still having the occasional warning saying large XTE and limit exceeded but no GPS loss of signal warning.Have noticed GPS green light momentarily goes off every 15 seconds. Is that normal?
I am going to contact Lagoon today phone coverage permitting as I have noticed that later model Lagoon 380 have the gos antenna in a different location and will try to find out why they moved it.
Thanks again for information

[magic8]

Just got some phone coverage back again
Will lose it tomorrow for a few days
GPS still not good. Suddenly comes up with large XTE warnings and SOG changing to 0 or 20 or something weird
I did call into a Raymarine dealer in Urangan that said he had heard of a couple of those converters doing a similar thing.
It is definitely not solar interference or radios because I did a night sail a few nights ago with no radios even switched on and obviously no solar
Not lights because it happens in the day.
Will contact the local dealer who has helped to see if we can try a new converter next week
Have attached photo which shows position on land before reset and correct position after GPS reset
Thanks

[Tom - Raymarine - Moderator]

Hello magic8,

I am very confident that this is not the convertor. Convertors just blindly pass the data through, they don't change it. I don't know where the dealer's got that information from, but I don't think it's correct. I've been specialising in Raymarine support for the best part of 20 years and summarised a lot of the collated experience from that time in the FAQ that I previously linked to.

Once again: to properly diagnose the issue you need a display or dealer with diagnostic tools that can read from the NMEA2000 network and see what the sats-in-view are and their signal levels over time. Replacing the intermediate STNG convertor will, I am pretty sure, not fix the issue.

Tom

[magic8]

Thanks for your info
Have just flown home for a few days and will be returning to the boat on Friday and the local dealer here has lent me a converter to try so we can confirm it as not causing the problem.
He has also suggested the way the Lagoon was originally wired may be causing the problem by drawing too much current through the converter as the wind instruments are powered via the 12v fed from the converter.
Just a few photos to show you how bad it is and we are now not able to sail at night.
The first one shows the boat in the incorrect position.
The second one shows the correct boat position after a GPS reset performed by the E80.
The third shows the rocks out on the port side but the incorrect boat position
showing almost going over the rocks on the starboard side!!!!!!!!
Will try changing the wiring as instructed by the local dealer if as you think the converter does not fix.
If there is anything else I can try whilst sailing back to troubleshoot please let me know.
Thanks again for help

[Tom - Raymarine - Moderator]

Hello magic8,

Pulling lots of current through a convertor isn't a good thing, but can't cause this sort of problem, it can't change the data as it goes through.

If you disconnect the RS150, you do lose GPS fix on the MFD (get a lost-fix alarm and the boat symbol disappears)?
Do you ever see static GPS position, that doesn't update as you move?

The reason I ask is that we often come across cases where there's a second source of GPS data that people aren't aware of, and we also sometimes come across data loops that can cause a static GPS position until a reset or power-cycle, at which time it will run again ok for a while until the loop reasserts at some unpredictable time in the future and the position is static again.

Other than these, I cannot think of anything useful I can get you to do without being able to read the satellite status direct from the antenna.
By the way, going back a couple of posts, I would advise not completely discounting RF interference. Everyone I've come across this has thought it highly unlikely until it's proven to be true in their case. Interference can come from almost anything electrical on the boat that has power and is more complex than an incandescent globe.

Regards,
Tom

[magic8]

Finally home after 5 weeks away and some good news I think until I read your last post!!
You were correct regarding the converter as we had the same results as before after changing it.
Also at the local dealers request we put some ferrite cores around the power cable to the converter to reduce any interference but the results were again the same.
The local dealer also requested after trying these 2 steps to rewire the existing boat wiring to to have the converter 12v power only power the converter and GPS antenna.The existing seatalk network was then powered from another source.We also confirmed that the A/P and E80 were not outputting any power.This obviously reduced the current flowing through the converter.
Have had 4 days and one night of sailing with no alarms or errors in position which has been happening at least twice a day
Hopefully fixed but not so sure now we have read your last post.Will have another sail soon and will let you know either way
Thanks again for all your help.

[Tom - Raymarine - Moderator]

Hello magic8,

I'll be happy and interested to hear that those changes have indeed resolved the problem - please let me know either way. If not, perhaps we can arrange to get something connected into the STNG side of the convertor to record what's happening with the satellite signal levels over time there. Who's the local dealer you've been working with, or where are you based?

Regards,
Tom

[magic8]

We are based in Bluewater, Cairns
Local dealer is Brian Swinton who has been awesome to deal with.
Will confirm next time we are out sailing either way but reasonably confident it is fixed due to 4 days with no alarms or incorrect positions.
Thanks again