Loss of GPS signal

[Sailfree]

OK Radar now working and intermittent loss of GPS signal/display on chartplotter.

No obvious loose connections on the bits I have moved.

Where does a GPS "plug" into a Raymarine system. I suspect the computer that links it all with the autohelm.

Anyone know if the signal a measurable voltage?

I assume its a 12V supply to GPS mushroom.

Every fault I have found so far has had nothing connected with the obvious - just things failing.

 

[[27631]]

cr*p Raymarine equipment...as i recall...there would be a small voltage up to gps antenna...thats how it gets its power..usually the fault is the gps antenna...made all over the place...by sub contractors....rubbish outfit...

 

[sailorman]

has the internal battery gone duff in the aerial

 

[pvb]

has the internal battery gone duff in the aerial

That would only make it slow to first fix after powering on.

 

[Sailfree]

Did not know they had an internal battery!

I have been fixing radar last few days and left the wind instrument on 24/7 to satisfy myself that the intermittant fault was a connection problem. After posting on here and googling last night I am hoping it's the batteries are low. Will put them on charge.

In firing up the E series to check the radar there was no position approx 50% of the time so thinking voltage is borderline.

 

[sailorman]

That would only make it slow to first fix after powering on.

Well mine wouldnt get a fix at all

 

[prv]

Where does a GPS "plug" into a Raymarine system. I suspect the computer that links it all with the autohelm.

Anyone know if the signal a measurable voltage?

There are a number of ways of getting a GPS signal into the system, but the most common one on a system like yours is a Seatalk GPS mushroom. It doesn't plug into any particular other unit, it is its own independent device on the Seatalk bus. It could be wired in anywhere, including into a spare socket on any other device or a junction box somewhere along a seatalk cable.

Seatalk supplies the power, it doesn't have its own separate supply, but the seatalk power conductors are indeed at 12v.

I've never tried putting a multimeter on seatalk, but I suspect it would look much like NMEA does - needle swinging back and forth apparently randomly, but quite distinctively, as the messages go by.

Pete

 

[duncan99210]

The GPS antenna on our Raymarine system is wired into the Autohelm control head via an otherwise vacant Seatalk socket. What you need to do is to follow the cable from the GPS antenna to where it joins the system, checking connections as you go. IIRC the Raymarine antennas do not have a battery fitted in them but rely on solid state memory for fast signal acquisition.

 

[Bathdave]

Well mine wouldnt get a fix at all

I had exactly same issue a few months ago, threads here and a local expert both pointed to investigating the little lithium battery, discovered it was soldered in, managed to lever it out and replace it....my local expert came and had a look and said he hadn't realised when we spoke just what vintage my mushroom was, and the whole unit needed to be replaced...so I did - not with a RM one but Digital Yacht ..almost.half the price.

Just wired straight in It works fine

 

[prv]

IIRC the Raymarine antennas do not have a battery fitted in them but rely on solid state memory for fast signal acquisition.

Maybe that's the case for some models. But the ones commonly found on a typical ST60 system certainly contain a battery, and it does eventually fail.

Pete

 

[sailorman]

Maybe that's the case for some models. But the ones commonly found on a typical ST60 system certainly contain a battery, and it does eventually fail.

Pete

Ask how i know & the bleedin thing is spot welded in place too, bluddy stupid design

 

[Pete7]

Ah, you have an early one, later ones had a plastic widget which holds the battery in place and much easier to change. I find they last about 5 years, done mine twice now and carry a spare battery on board. CR2032 from memory.

 

[nimbusgb]

Raymarine gps pucks can be wired to work as either NMEA or seatalk output. Could be duff connections, power any number of things.

Any GPS system needs some sort of memeory retention system as ephemeris data is required to get get a position from a warm start rather than a complete 'find yourself forthr first time' scenario.

A methodical approach to debugging is whats needed.

 

[Bathdave]

Raymarine gps pucks can be wired to work as either NMEA or seatalk output. Could be duff connections, power any number of things.

Any GPS system needs some sort of memeory retention system as ephemeris data is required to get get a position from a warm start rather than a complete 'find yourself forthr first time' scenario.

A methodical approach to debugging is whats needed.

I think what's missing is what model is it, when does it date from and when was the battery last replaced. Mine was 12 years old and the battery never replaced, it was not a serviceable item in that model RayStar.

Answers to these questions well point pretty firmly to whether it is that or whether a more forensic debug is likely to be any benefit

 

[CJ13]

As others have said it's almost certainly the internal battery. If yours is a 125GPS it's very easy to change the battery. Undo the screws holding it together and it's obvious - takes 5 min max.

John

 

[Sailfree]

As others have said it's almost certainly the internal battery. If yours is a 125GPS it's very easy to change the battery. Undo the screws holding it together and it's obvious - takes 5 min max.

John

Went on boat and its working 100% at present. If it fails again I will look at internal battery. Any probs and I will cut my losses and buy a new one from Greenham Regis as they have been so helpful in solving my other probs.

 

[stuartwineberg]

That would only make it slow to first fix after powering on.

Nope - on the Raymarine ones it kills them - loads of threads on this.

 

[pvb]

Nope - on the Raymarine ones it kills them - loads of threads on this.

It doesn't kill them. The battery is simply to preserve a memory function, which remembers the last fix, thereby making it quicker to find a new fix once repowered. Without the memory, the Raystar will eventually find a fix, but it will take longer than most people will wait. If you Google raystar battery you'll find lots of threads confirming this.

 

[sailorman]

Mo o/b lappi uses a Maplin £20 usb dongle gps siks flexed in a window
Raymarine cost £230+ there is no difference in reception between either gps

 

[oldgit]

In the past have tried several odd ball GPS recievers from assorted "free" sources to replace a raystar unit.
Main problem with lapstop usb jobbies is need to get 5v or whatever powers it up.
A couple of other gps receivers simply would not work Raymarine set up.
You can detect a signal from functioning GPS receiver with a simple multimeter.
Normally a volt swing from 3v to 7v ish.