View Full Version : Mounting location for GPS Gaffrig speedo antenna

tylogans 22
04-10-2012, 01:46 PM
I'm getting ready to install a Gaffrig GPS speedometer in my 22 Classic, has anyone installed the antenna under the deck?

I really don't want to install this on the exterior if I can avoid it.

04-10-2012, 02:10 PM
Gregg, mine is under the deck with no problems what so ever.

Do it.


04-10-2012, 02:40 PM
Mine also....no issues...


04-10-2012, 04:25 PM
I've mounted several GPS's inside cabins with no problems. On my own 22 however, I happened to mount the Livorsi GPS puck flush on top/center of the dash, sort of 'under' the windshield.

tylogans 22
04-11-2012, 01:08 PM
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when you mounted under the dash was there any peticular place that you installed located it?


04-11-2012, 01:36 PM
I'm also curious what people have done on this front.

The general rule I've heard for GPS antennas is to go on centerline, lower, and further aft, when possible. To minimize the effects of motion of the boat. Makes me wonder if something under the rear deck would work, if shooting through the deck isn't an issue.

04-11-2012, 03:09 PM
Being an old tech I have rigged more than my fair share, under deck works great no issues. I have always mounted then to the opposite side from the dash to eliminate any possible interference. I have been out in some very bad seas including two hurricanes, I have never seen motion affect the signal. The passenger side step well is where mine has been for four years, mounted on a simple aluminum bracket.


04-11-2012, 03:12 PM
Gregg, if my memory serves me correctly, I mounted it infront of the fuse panels by a foot or so and some what close to the centerline of the deck. Had lot of wire left over.

I kinda just picked a spot.

If the boat wasn't 300 miles away, I would shoot you a photo.


04-11-2012, 04:58 PM
Under deck sounds like the way to go. I mounted a Sirius antenna under the deck and it works fine. Similar very low power signal receiver.

Certainly try it first under the deck..You can always cut holes later.

tylogans 22
04-12-2012, 11:07 AM
Thank You for all the feedback- Under the deck it will be.

thanks again,

22 Yellow Devil
18 Carleson Glastron CVX 18

04-12-2012, 11:37 AM
To address Mike's questions - I don't think you'll find any benfit to mounting the antenna at a different point on a small boat like this. Heck, even a large boat wouldn't have any real impact on the GPS performance. The only thing I'd worry about is making sure it had a decent veiw of the sky - either direct line of sight or through a relatively thin layer of fiberglass like a deck. On large boats I don't like to mount internal antennas in a pilothouse as there would be a fair amount of metal in the sturcture that would obstruct the signal. But then again, thats why large chartplotters have exteran GPS inputs and not integrated recievers like the small ones do.