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Posted

I've recently installed a Raymarine A57D chart plotter/fishfinder on an Alumacraft Trophy175 aluminium fishing boat.

 

It takes a long time for the GPS to acquire satellites and get a fix. And it often drops them, losing the fix.

 

If I'm headed north, I get much better reception. But if I'm headed south, and the windshield occludes the southern sky, I get 4 birds, maybe 5 at best, and I lose my fix.

 

The unit sits on the dash, in behind a glass windshield (Taylormade windshield). The boat has no hardtop or canvas. Except for the windshield, the unit should be able to see the full sky all the time.

 

I've talked to Raymarine and the retailer (local guy who I know well). They both say this antenna has a good track record; no record of complaints.

 

Raymarine gave me a compact flash card with the latest software to install. I was hopeful that would help, but found that my unit already had the latest version/build. Argh!

 

Raymarine tech support suggested I set my SOG/COG filter to high, but I know this won't help me hold a satellite signal.

 

I'm facing 2 options;

1. Take the unit off and ship it to Raymarine, which means I'll lose it for weeks and weeks, or

2. Buy the external antenna (>$300). The whole unit was <$800, so I'm not thrilled with spending more than $300 for an antenna.

 

Any advice, before I try option 1?

 

 

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Posted

not sure on how old your unit is but on some of the older lowrance lms series if you didnt have the waas enabled it would not find your present location very well and would cut in and out,as well cause its an internal antenae make sure the unit is as verticle as possible not leaned bak on a slant as most of the antenae is on the top,my lowrance was like that too,and that was about 5 years ago ??/ just shootin out ideas for you too try ??/

Posted

well the first thing is to move it

 

just temporary to test if it works better else where

maybe even a ram mount would move it away from the windshield enough ..but test it other places befoe you spend money

Posted

not sure on how old your unit is but on some of the older lowrance lms series if you didnt have the waas enabled it would not find your present location very well and would cut in and out,as well cause its an internal antenae make sure the unit is as verticle as possible not leaned bak on a slant as most of the antenae is on the top,my lowrance was like that too,and that was about 5 years ago ??/ just shootin out ideas for you too try ??/

That was what came to my mind too but I think the issue on Lowrance was when the "Require waas positioning" option was selected. I'm not sure if the Ray has that feature but worth a check.

I'd agree with Terry (just this once ;)), perhaps relocating it might narrow down the issue.

Posted (edited)

yup, try moving it. My Lowrance ext. ant. wouldn't work worth beans in front of my Taylormade Windshield...

 

That's interesting Dax, I've got a Lowrance Globalmap 7200 GPS that sits on the dash right behind the Taylormade windshield and the external antenna is only inches infront of the windshield and everything works perfectly.

 

Infact the antenna is fine even when it's covered by the bow cover.

Edited by lew
Posted

Terry has a valid test idea. I have a hds7 with an internal antenna that shoots thru an aluminum hard top and tempered 1989 glass. Some of the treatments to windows will block the signal.

 

Art

Posted

Terry has a valid test idea. I have a hds7 with an internal antenna that shoots thru an aluminum hard top and tempered 1989 glass. Some of the treatments to windows will block the signal.

 

Art

 

The Lowrance HDS internal antenna units are much improved over the LMS units....with the older LMS internal antennas, the unit needed to be many times upright....where some units installed in the dash at the bow were tilted and reception was a problem.

Posted

Thanks for the help everybody. It looks like I need an external antenna. My problem is the Taylormade windshield; it must have some unique coating in the safety glass lamination.

 

I removed the GPS unit from the boat, and made up a jumper so I could power it up remotely using a 12VDC jump box. Standing on my dock, holding the GPS unit in my hand, the nearest building is about 200' away and I picked up 10 or more satellites (on average).

 

Then, still using the jump box power supply I returned the plotter to the boat (on the trailer in the barn) but not under the shadow of the windshield. Still had 6 satellites or more, while in the barn. Moving it under the windshield near its mount dropped me to 4-6 satellites, and all weak signals. And the unit couldn't find those satellites again if I restarted the GPS.

 

I then returned the plotter to its proper dash mount and reconnected it to the boat's power supply and pulled the boat around with the tractor. As long as the windshield wasn't between the unit and the southern sky, I was OK.

 

So, it's that damn Taylormade windshield. Who's got a new Raystar 130 for sale, cheap?

Posted

I would return the Raymarine unit and get an HDS. A lot of people on the board have them so there is no shortage of experienced technical help. Mine sits right behind my windshield and has no problem acquiring a fix and holding it even inside my boat house.

Posted (edited)

I would return the Raymarine unit and get an HDS. A lot of people on the board have them so there is no shortage of experienced technical help. Mine sits right behind my windshield and has no problem acquiring a fix and holding it even inside my boat house.

 

 

Good advice Cliff, except I shot myself in the foot... I've fully installed the unit. And to do that properly, I cut and spliced the transducer cable, and I shortened the power cables. All my electrical connections are crimped and heat-shrink sealed and the NMEA0183 conductors are tied back and insulated. It's really not in the same condition as when I bought it. And I recycled the box!

 

To add to it, I've discovered that this Taylormade windshield causes problems for other GPS units too.

 

I'm short on options here, so I'll get the external antenna. I will be asking Raymarine to get me their best deal on the antenna.

And by best, I'm thinking free. angel.png

 

 

 

.

Edited by whiskywizard
Posted

You could borrow my Taylormade Driver to remove your Taylormade windshield.

 

It's left handed though whistling.gif

 

 

biggrin.gif

Funny.

 

But why are you playing left-handed? Was your right-hand game soooo bad that you had nothing to lose?

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