GPS w/internal antenna??

[hassm]

I have a T-Top. Will a Garmin GPS with internal antenna work? Or will I need an external antenna?

[pastaman1234]

Should work. See if your car gps acquires a signal on the same spot!!

[HeadHunt]

Mine will not work on the dash. I am pretty sure it is because I have a large aluminum e-box under my top that blocks everything. You should be OK just through the canvas.

[llord]

Fiberglass wont effect the signal. To much metal will. For what its worth I've never had one not work

[DefenJohn]

If it doesn't work the external antenna add on is usualy 50 dollars or less for their smaller screens.

[CMEBoston]

Originally Posted by llord

Fiberglass wont effect the signal. To much metal will. For what its worth I've never had one not work

Not %100 true, fiberglass can reflect the GPS signal and send the same pulse into the reciever twice affecting the signal timing therefore affecting the GPS position.(GPS is a Signal/Time based system) if flushmounting it is always reccomended to use an external reciever.
EDIT, I am not trying to say that you wont have sattalite reception, just watch out for strange position data with your chartplotter.

[rwidman]

My 182c with internal antenna worked fine on my previous boat with the bimini top up. It worked fine in my Camano at the lower helm with a fiberglass floor above it (look at the photo).

I installed a pair of 5208s and installed the external antenna under the (1 1/4" thick) fiberglass dash on the flybridge. It works fine. Gets the maximum number of sattellites at full strength.

So - I believe you'll be fine with your T top.