Lowerance GPS loses position

Bulligmore · 26 March 2008, 11:25

I have a Lowrance 520C, the antenna is mounted on the dash consol. It keeps losing position every 5 - 30 minutes. I have changed the antenna, same problem. The Raymarine never has a problem, it has the antenna on the A frame. Thanks for any help.

v666 · 26 March 2008, 12:25

Is the 520 c also a sounder ?

Does the GPS cable (raymarine) and the sonar cable run close to each other through the trunking ?

Try using the lowrance alone with the raymarine switched off. If it works it then has someting to do with the above 2 wires.

I have a lowrance chartplotter and a huminbird gps/sounder. If I turn on the Lowrance I loose the gps signal to the huminbird

Tim

Poly · 26 March 2008, 14:14

Stupid question - but is that the gps ariel on the left of the console. Should it be mounted horizontally (i.e. dome pointing straight up)? I'm not sure how sensitive to being at an angle it might be? It may be the angle the photo was taken but it looks as though it could almost be 45 deg out and then with the bow going up it would get worse. Alternatively is anyone getting between it and the "sky" - my handheld certainly works better if no one is leaning over it.

Bulligmore · 26 March 2008, 14:24

Thanks Tim.

The GPS cable (raymarine) and the sonar (lowrance) cable do run togeather. Trouble is you have to drive for 30 minutes or so to find the problem.

Do you know if the antenna is OK in this position, I understand that if some puts there head over it I could lose the signal. But what about the angle. I have seen antenna in the same place on other RIBs.

John

jyasaki · 26 March 2008, 15:32

Don't know about the antenna angle. I have a 520C with the antenna on top of the A Frame (and mounted flat) and have yet to lose lock.

Do you lose *all* satellites, or just enough so it doesn't know where it is?

If it's all, I'd suspect something like an electrical connection (perhaps power to the NMEA 2000 bus?)

If it's some, I'd suspect the antenna orientation is screwing things up.

jky

BruceB · 26 March 2008, 17:12

Try making sure the WAAS is not enabled. Apparently if this is enabled it says it has lost lock anytime it cannot pick up the WASS signal.

Bulligmore · 26 March 2008, 19:21

I will try switching off WASS because I did notice it said it was working and I don't think it does in Ireland.

What I would like to know is, does the angle of the antenna make a difference. On my hand held map 76 it makes no real difference except if you block the signal.

In the picture the raymarine has 8 locks using the a frame and the lowerance can hardly get 3.

John

BruceB · 26 March 2008, 22:14

Reading through the Lowrance manual for this aerial it seems to me that you could not call the mounting position "a clear view of the sky"
I would try mounting it horizontally and see what happens.

Texel Tom · 26 March 2008, 22:44

Are you getting 'GPS Module Not Responding' or 'Position Lost' ?

TT

Simon B · 27 March 2008, 11:09

During the extensive tests we did to try and fault find our GPS module we did try it upside down and covered up with someones hands, miraculously it still updated it's position.

The error message Texel Tom referred to was the begining of the failure of our module, it showed this every now and then, with a downpower/repower fixing it until the fault went hard and the module did not respond at all. We had to get a new module which we will monitor very carefully. I beilieve also that the LGC2000 software updates contains a loose refrence to better performance near radar, though, not sure how this would impart more robustness to the unit.

Texel Tom · 27 March 2008, 11:43

'GPS Module Not Responding' denotes a communication failure between the antenna and the unit and can be the result of a power failure to the module or a fault in the module itself. The LGC software update to which you refer included enhancements which enabled the antenna to re-set itself after being hit by radar and later modules had additional shielding.

'Position Lost' means the satellite link has been compromised. Looking at the picture it could possibly be the installation and the first step would be to try to re-create the error with the antenna positioned horizontally and also 'Require WAAS' must be disabled in 'GPS Set Up' .

You should also consider installing the latest software version for the LMS520 which is 2.3.0 released on the 10th March. The antenna should be running v.1.9.0 and information on this can be found in your device list under 'NMEA2000' (Networking)

TT

Bulligmore · 27 March 2008, 16:08

The error is Position Lost.

I think that makes sence, I will move the antenna on to the grab rail infront of the screen and make sure the WAAS is off.

Thanks to you all for your advice.

John