Marine Electronics Forum - GPS Antenna location

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View Full Version : GPS Antenna location

06-04-2007, 12:12 PM
I went out on a friends boat to do a little bottom fishing. I tried entering my waypoints and noticed that his Raymarine RL70c lost it's fix. I turned on his Lowrance backup LMS-337c...also no fix..all day 6, hours. We got our fish and used radar to return in the fog. All other funtions on the machines works fine. I'm thinking lack of power or antenna location. His 23ft Seaswirl hardtop has both antennas mounted on top of the cuddy cabin just in front of the windshield. I had my hand held Garmin and was easily able to track 8 satellites. Are these antennas mounted too low?

Bill (

06-04-2007, 12:25 PM
Something does not sound right. I have my GPS Antenna mounted under the console which is under the hard top and I've never had a problem locating a signal.

06-04-2007, 12:29 PM
Shouldn't be an issue. WHen you used your Garmin were you under the hardtop? Here's my install .... have great reception from this location. Used to have a Raymarine 435 GPS antenna mounted in this position ... no issues whatsoever. :grin:

06-04-2007, 12:53 PM
depending on the age of the antenna, if located too close to the radar, that can cause a problem.

06-04-2007, 12:55 PM
Also, I had a small lowrance on an older boat. The antenna did not tolerate any radar signals and would get burned out. Lowrance had some issues a while back with that. Height of the gps antenna shouldn't matter (unless it is to get it out of the radar beam).

06-06-2007, 02:20 PM
Lowrance replaced their early GPS antenna modules with better shielded ones. There was a problem with proximity to Radar that would fry internals of the Sat Antenna amplifyer circuitry. Once toasted, its not gonna work. Height is not the problem but the GPS antenna needs to be somewhere less susceptible to the Radar beam. He will have to call Lowrance to see if he qualifies for a free upgrade.


06-07-2007, 10:30 AM
lowrance says to keep antenna 3 ft or more away from the base GPS unit . mine would lose signal (4" away) and I moved it ,works fine now (it would be great if they put this info in the manual)

Domino Effect
06-08-2007, 12:41 AM
I have my 2 antennas mounted on top of my console, thru out the day all kinda crap gets thrown up there including shirts and never lose a signal, my only problem is if I get up under the wrong side of a rig I lose my XM occasionally.

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