Which GPS Antenna for my Garmin?

[Perithead]

I have a Garmin GPSMAP 440s and I am looking for an antenna for it.
I found two on WM and I am trying to decide which one to get, if either.

The first is a small mushroom like antenna ($63) (GARMIN Antenna at West Marine) that seems like it can be mounted under the cabin top and I wouldn't have to drill another hole in my boat, I like this idea. I have read that the new antennas have no problem gettnig signals through fiberglass.

The second is a little low profile one ($30) GARMIN Antenna at West Marine. I guess this one would just be placed somewhere secure below and it should get a signal? I like it because it's cheaper for one and it also has a cable on it already. Would this one work for my application?

Thanks for your input!

[barnakiel]

Getting an external antenna and mounting it inside?

Why?

b.

[sabray]

Originally Posted by barnakiel

Getting an external antenna and mounting it inside?

Why?

b.

Because it comes with an internal mount. Gamin says it's okay to do this flush against the deck without obstructions above the mounting place. It has worked for years and is very accurate. It is not subject to weather or another deck penetration. Thought it was worth trying and other then the nmea failure it has been proven good. Really why stick it up side until you determine you need to. I didn't do this Willie Millie gave it some thought. Happy to hear your respected opinion why I should reconsider.

[DeepFrz]

Try this place.

View Product Garmin GA 30 remote antenna

[barnakiel]

Originally Posted by sabray

Because it comes with an internal mount. Gamin says it's okay to do this flush against the deck without obstructions above the mounting place. It has worked for years and is very accurate. It is not subject to weather or another deck penetration. Thought it was worth trying and other then the nmea failure it has been proven good. Really why stick it up side until you determine you need to. I didn't do this Willie Millie gave it some thought. Happy to hear your respected opinion why I should reconsider.

OK.

I found our gps units less reliable when down below. I believe this relates to signal strength and to the number of satellites that are visible to the unit.

Hence my idea that external antenna delivers best performance when mounted externally.

b.

[senormechanico]

I have a GA 30 mounted behind the acrylic windshield just ahead of my instrument pod.
It always works great with ten to twelve satellites at any given time. Boom and or dodger has no effect on it no matter how much it rains.

[bobconnie]

Gee with all the thru deck anti-leak stuff available today why are ya sweating another hole thats above the water line ??? stands to reason you will get a better signal with a outside antenna mounted outside then ya will with it mounted inside ! Ive seen a decrese in signal strength with my hand helds when below decks! not much but it's less! Just saying they don't call em exturnal for nothing!!

[sabray]

Yes I saw decrease in signal strength with some units. The antenna is below deck hard against deck. Zero exposure. It has been very accurate over 4 years of very active cruising. C&d canal dead on 4 times. Chesapeake bay multiple harbors dead on. Connecticut river twice I to narrow harbors within feet. Baltimore marthas vineyard, Newport port Jefferson, block island Cuttyhunk north port, east river. All dead nuts on. Why would I put it top side? If it didn't work that would have been the option. At this point it's proven as a reliable set up. Installed per manufacturer guidelines. You can tell me it doesn't work . You can stick your nav stuff on a rail. Mine works without a few extra pieces and it's below decks.

[Cotemar]

Garmin’s external antennas work fine just underneath the deck. They are rated, tested and meant to work that way if you so choose. Fewer wholes in any boat are a good thing. Also makes for an uncluttered look.

[sabray]

Originally Posted by bobconnie

Gee with all the thru deck anti-leak stuff available today why are ya sweating another hole thats above the water line ??? stands to reason you will get a better signal with a outside antenna mounted outside then ya will with it mounted inside ! Ive seen a decrese in signal strength with my hand helds when below decks! not much but it's less! Just saying they don't call em exturnal for nothing!!

Why do anything that exposes things more if it works without. Surprised you are like what? Past owners had the rig mounted in the stern rail. looked like a trident. Very nautical with all the crap sticking up. Sabray is clean and efficient. Nothing is exposed that should not be. If my stern rail is ripped up it's just the rail. Not my nav system.

[sabray]

If I had a whistle. Well I dont so I'm putting my lips together like this it's like this and then you just blow. Kinda harsh on me no. I usually enjoy your posts sometimes I do things a tad different. After ( time to whistle you remember how to whistle don't you ) 35 years of sailing . I kinda get to try some ideas that close up some issues. Uv wire fatigue etc... Damn thing works and garmin says I can install like this. Blowing hard with my lips all pinched up

[senormechanico]

Originally Posted by Cotemar

Garmin’s external antennas work fine just underneath the deck. They are rated, tested and meant to work that way if you so choose. Fewer wholes in any boat are a good thing. Also makes for an uncluttered look.

Just don't mount it where you sit or lay your arm.
You'll go from 12 satellites to zero.
Before I mounted my Garmin, I tried setting it in a pooka between a couple of winches as it seemed like an easy install.
It was perfect until i laid my arm across the settee back.
Signal went to el zilcho.

[barnakiel]

Originally Posted by sabray

If I had a whistle. (...)

Baaaaad boy Sabre ;-)

If you truly want to have it all sleek and reliable, you can place the antenna outside - in the least likely to be hit place (e.g. under the dodger) while a cheap handheld can be used as an emergency unit.

Then you win two ways:

1) the antenna is where it should be - outside and in full view of ALL visible satellites, this ensures the most reliable GPS navigation,

2) should you main gps unit get smashed (like from a flying saucer - and I mean it - a real teacup saucer sent on its way by a nasty wave) you will have a spare, COMPLETE nav solution!

Hugs,
b.

[noelex 77]

The modern gps. Units do give remarkable results when used down below. In marginal conditions the quality of the fix is still not as good,however. I think the gps is such an important instrument it should be installed without compromise.
The only real drawback of a propper external aerial is more vulnerable to damage. So make sure you have a backup. If you install 2 fixed units put the aerials in different locations, preferably on separate sides.

[noelex 77]

Cotemar

Some of those power cables, particularly the larger gauge wires look a bit too close to the compass. If possible twist them together, and if you have excess wire try not to make it into a loop close to the compass.