lost GPS fix

[captainKJ]

I think it is a conspiracy with beneteau against hunters. They were trying to run you down to get you to buy a beneteau sailboat. BE CAREFUL here Don,,,,

never can tell when it will happen again. Keep a goo lookout for other sailboat that are beneteau,,,especially by a reef. Keep the paper charts out just in case.

On another note it could be a bad chart plotter. The first one I had on my jetski had to be returned to garmin after 4 months. they had a bad batch and replaced it for free,,,gps and all

[sailorboy1]

no it was an antenna problem because both my chart plotter use the same antenna via Seatalk and both lost their fixes, the only other choice would have been a signal jammer

you would think Ray Marine would put something in their manual abut a battery needing replacement

[s/v Beth]

I don't think they expect owners of second hand chartplotters read the paper documentation- usually gets lost somewhere.

[Pete7]

Originally Posted by s/v Beth

I don't think they expect owners of second hand chartplotters read the paper documentation- usually gets lost somewhere.

I think they expected owners to replace the whole system when the signal is lost and it doesn't work any more. Probably quite a good business model for Raymarine in the last decadent decade.

Peter

[highseas]

My Raymarine C80 lost GPS signal a few days after the antenna got a really good soaking.Replaced the Raystar antenna and all was good.Not sure how water got into it.

[sailorboy1]

I was on the Raymarine site last night looking more into this battery thing in the antenna. I'm pretty sure it has one because it is in the technical specs for the unit in the unless manual on my boat (online I found there are lights on the thing to diagnose, you would think the manual would have these in it). Nowhere on the RM site could find I find anything about the antenna having a battery. There were various FAQ threads about losing the fix and they all talked about checking connections for the power to the chartplotter for the antenna and would lead one to believe that is where the power comes from. wonder what that battery really does in the antenna?

[jackdale]

Originally Posted by ZenithOcean

Many large yachts (i.e 60m+) and cruise ships are designed to be paperless, although generally use paper charts when near coastal.

But they do not use chartplotters; they use redundant ECDIS.

[mrm]

Originally Posted by Don Lucas

wonder what that battery really does in the antenna?

Could be it was left there to find its own purpose in life but most likely it backs up power to a memory holding the recently received almanac.

[cas206]

Originally Posted by mrm

Could be it was left there to find its own purpose in life but most likely it backs up power to a memory holding the recently received almanac.

I would tend to agree. The built in battery helps a GPS receiver keep date, time, approx position, and almanac data (i.e. data that lets you know what satellites are visible) in order to reduce the time to first fix. If unit loses this information due to battery issues, it "should" (unless poorly designed) still work, it will just take longer to get a first fix.

[John A]

When your gps unit displays that it "lost fix", go to the display that shows how many satellites signals are being received. A minimum of 3 are required for 2D and 4 for 3D.

Your unit must receive the required signals, figure out the distance the satellites are from your receiver and do a reather complex trigonometry calculation involving triangulation and cosines. Any gps unit is continualiy dropping and reaquairing signals. If the whole calculation thing is interupeted, you receive a generalized "lost fix" message.
The battery in the antenna. I believe, is used to assist in sorting out the satellite's distance by measuring the time that it took for the signal to arrive at the antenna, and transmiting that information to the gps unit. Yes, you can mix and match antennas and receivers but it's unwise.
If you have any other antenna close to the gps antenna, the two can confuse each other. If the antenna is moving around due to rough seas, or is mounted on the spreaders, the signals can be interrupted.

Restart your unit to force it to start from square one again.

As with your radar unit, do not shorten the cable from the antenna to the receiver!. The timing of the signal is very important.

[Pete7]

The only reason we knew there was a battery inside the antenna was we took a spare one apart. A friend had the same fault as me, slow to find the position and often dropped the signal.

Said friend worked at Raymarine at the time so he asked the techies the reason for the signal being lost and then coming back on later. They couldn't explain it but he did acquire a spare 125 antenna which worked. So now we had 3 and took one apart. The photocopy of the circuit board I posted was taken on a Raymarine photocopier because the techies didn't believe there was a couple of watch batteries inside

http://www.cruisersforum.com/forums/...c80-52914.html

Now, how long does your watch battery last and what are the symptoms when it fails? Now ask yourself how old is your Raymarine Antenna?

You just need a set of small screw drivers and a steady hand, nothing special.

Pete

[sailorboy1]

I haven't gotten around to that battery. But it has been weeks now without any problems. I've even been to that same spot where I lost the fix without any problems. I will get to the battery but the whole freakin thing is starting to have that PFM feeling to me.

[Wotname]

Originally Posted by Don Lucas

I haven't gotten around to that battery. But it has been weeks now without any problems. I've even been to that same spot where I lost the fix without any problems. I will get to the battery but the whole freakin thing is starting to have that PFM feeling to me.

Perhaps a relevant question might be "what had you been drinking" just before the first occurrence of this problem .

[sailorboy1]

diet coke

[captainKJ]

Originally Posted by Don Lucas

diet coke

mixed with WHAT???????