Raymarine Seatalkng/N2k Losing GPS/AIS signal

[zboss]

All,

I wonder if this is a general issue with raymarine products or just our system. We have an system that keeps losing GPS fix and subsequently loses AIS (we have separate GPS and AIS antennas). It drops out and then comes back some indeterminate time later. I believe the GPS antenna goes directly to the chartplotter.

We did not have this problem with our old Garmin system on our first boat.

Thinking that it was perhaps a bad GPS I installed another device that is a direct Airmar N2k GPS so it can run independently and have GPS when the chartplotter is not on so I could use my other instruments and provide GPS to my VHF. Then I turned off the GPS on the chartplotter.

Same issue.

I am wondering if maybe there is something on our boat causing a signal issue. My phone never loses the GPS so if it is something on the boat then it would have to be something electrical that is close to an N2K wire. BTW - we don't lose other messages like depth or wind speed. I would think that if its a wiring problem we would lose signals from other sensors periodically as well.

I'm stumped. Ideas?

- z

[GreenWave]

Use the Google Custom Search feature in the forum menu and search for this topic. I just read through a number of older threads on similar topics. Lots of potential causes.

[manitu]

How is your nmea2000/seatalkng backbone set up?
Power feed and terminator?
Other units?

.manitu

[smac999]

the AIS targets will disapear when the plotter loses GPS. that is normal on every plotter I've seen. so most likly you only have a GPS issue. and don't worry about losing AIS targets for now and just fix the Gps.

if it happened the first time while using the internal GPS. then it shouldn't be a network issue...

does your VHF lose gps? they normally have a 5-10min delay though so they are harder to check issues on losing GPS.

[continuouswave]

Originally Posted by smac999

the AIS targets will disapear when the plotter loses GPS. that is normal on every plotter I've seen...

That behavior seems very odd. An AIS receiver connected to a chart plotter sends the position of targets. Why would the chart plotter stop displaying them?

[Captain Bill]

What model of chart plotter do you have? Also where is your GPS antenna mounted. I believe Mantas have an aluminum honeycomb hard top and I know they have an extensive supporting frame. All that metal can interfere with GPS signals. I have two friends with Mantas and they have their GPS antennas mounted on the top of the arch. If you are using the internal GPS of the chartplotter under the hard top it might not be getting much of a signal especially at certain satellite angles. At least on newer chart plotter models you should be able to set up your Airmar GPS as the GPS data source if it's more stable than your chartplotter GPS.

[twig]

I had same problem and double checked my connections and it went away

[Redline452]

Originally Posted by continuouswave

That behavior seems very odd. An AIS receiver connected to a chart plotter sends the position of targets. Why would the chart plotter stop displaying them?

Because it wants to display the targets with respect to your own position, which it no longer knows?

[Markb250]

I have had a similar "mysterious" issue with Raymarine gear, which I was eventually able to resolve. If this doesn't help you, it may be of future interest to others, so:-

The satellites were either very slow to load up for a fix, or there was no loading at all. Among the many items I checked, I initially noticed that the cable from the antenna had some very minor damage to the sheath. I could see the separately insulated cables through that little nick and they looked undamaged, so I ruled that out as the problem.

Having endured the problem a little longer, I decided to split that cable sheath open for a better inspection and low and behold, although those cables are insulated, one of them is not and this one had corroded away. I assume that intermittency was due to whether there was moisture present to make a connection, or not.

[zboss]

Originally Posted by Captain Bill

What model of chart plotter do you have?

Its a Raymarine e125.

Originally Posted by Captain Bill

Also where is your GPS antenna mounted.

Externally, on the arch. The Airmar GPS sensor is at the top of the mast and sends data over N2K - so a completely different mechanism than the chartplotter external GPS antenna.

The VHF gets its GPS position by N2K from whatever source is set.

Originally Posted by manitu

How is your nmea2000/seatalkng backbone set up?
Power feed and terminator?
Other units?

Power is steady at 12 volts unless we run the windlass. Remember, its only a GPS that loses contact and from two different GPS. Not the depth or wind sensors. N2K data is N2K data. It's a reasonable assumption that if all the other data is getting through then the GPS data should get through as well, unless there is a conflict somewhere but we only had one GPS until recently.

At this point, since the power on the chartplotter is separate from the N2K cable, I am going to disconnect the N2K cable from the chartplotter and set the chartplotter to use its own external antenna.

[Captain Bill]

Originally Posted by zboss

Its a Raymarine e125.



Externally, on the arch. The Airmar GPS sensor is at the top of the mast and sends data over N2K - so a completely different mechanism than the chartplotter external GPS antenna.

The VHF gets its GPS position by N2K from whatever source is set.



Power is steady at 12 volts unless we run the windlass. Remember, its only a GPS that loses contact and from two different GPS. Not the depth or wind sensors. N2K data is N2K data. It's a reasonable assumption that if all the other data is getting through then the GPS data should get through as well, unless there is a conflict somewhere but we only had one GPS until recently.

At this point, since the power on the chartplotter is separate from the N2K cable, I am going to disconnect the N2K cable from the chartplotter and set the chartplotter to use its own external antenna.

It is my understanding that the e-series does not have a port for an external antenna. Are you sure it's just an antenna and not a Raymarine GPS like an GPS 120 or 125. These GPSs have an internal lithium ion battery that must be replaced occasionally. I have a 125 that is now about 8 years old and has stopped working. It is my backup GPS. I was told to expect 8 to 10 years before replacing the battery In the earlier GPSs such as the 112 the battery was not replaceable and you had to throw it away when it failed. That's how I got my 125. When I replaced my old RL70 in 2014 I kept the 125 as backup. They had a program at that time where you could get $100 off the new ones if you had a one of the ones that the battery could not be replaced in. I would note that in the old 112 when the battery was on its last leg I would have position drop outs all the time. That is when I took it in to the local Raymarine shop and he explained about the battery issue. I currently have a C97 which is the same vintage as the e-series just with knobs and buttons instead of a touch screen. If the GPS was purchased at the same time as the E125 it's probably time for a battery replacement. Although I have not opened mine yet I was told they are like a lithium watch battery, not rechargeable types.

[hanjohuizing]

I have had the same problem, there is an easy fix. Unscrew the three srews at the bottom of the GPS and replace the battery. If the battery is dead it will not keep its position and takes a long time to fix again if it looses signal. Battery is a standard lithium battery, I believe something like a CR 2032 ( not 100% certain, you need to check). Replacing it is is 5 minutes work and it should work again. Battery life is some 2-3 years normally.

[Captain Bill]

Originally Posted by hanjohuizing

I have had the same problem, there is an easy fix. Unscrew the three srews at the bottom of the GPS and replace the battery. If the battery is dead it will not keep its position and takes a long time to fix again if it looses signal. Battery is a standard lithium battery, I believe something like a CR 2032 ( not 100% certain, you need to check). Replacing it is is 5 minutes work and it should work again. Battery life is some 2-3 years normally.

Before the battery was totally dead did you have drop outs on your GPS like I did on my old unit?

[hanjohuizing]

Yes exactly same thing, frequent drops of gps position and it took maybe up to 20 minutes or soo to get a ]new position. The gps starts searchong satelites on a satelite position agenda that is 15-20 years old. The backup battery prevents that.

[Captain Bill]

I drug out my manual and have confirmed that the E125 does not have a connection for an external GPS antenna. Any GPS connected to it has to be an active GPS, so I'm pretty sure we are on the right track here. I have confirmed that the Raystar 125 GPS can be connected via NMEA 183, Seatalk Ng, or Seatalk. It would not matter which method was used to connect the GPS to the plotter or other instruments if this is a battery problem.