*THE HULL TRUTH is the world's largest FREE network for the discussion of Boating & Fishing. Whether you're researching a new boat, or are a seasoned Captain, you'll find The Hull Truth Boating & Fishing Message Forum contains a wealth of information from Boaters and Sportfishermen around the world.
Welcome to the updated THT!
If you are having trouble signing in, please email feedback@thehulltruth.com with your username and we will help you. We thank you for your patience as we help you access the new site!
Random Quote: It's easy to simulate the joys of boating. Just stand in a cold shower and tear up $100 dollar bills
I have bought my first GPS/Chartplotter and am trying to decide where the best place to mount it might be. The head unit will be mounted inside an electronics box which sits atop the console There is no T-top, but a 17" high windshield of (plexeglass?) is atached to the front and sides and a grab rail goes over the whole thing. Best place is probably a rail mount, but there is no good way of dealing with the wire other than drilling a hole in the rail and I don't want to do that. The second place is atop the electronics box in the corner next to the windshield, This give the antenna a clean shot straight up but three of the sides will be obstructed by the windshield. Will this cause problems with reception? Any other ideas on where to mount this thing? In this case, off the console is not really an option.
Also, all those little wires which have to connected....is it best to bring them to a connecting block or try to use butt connectors and make the connections direct.
Thanx,
Rocky
When we first purchased our GW Islander 270 in February 2002, it had a soft top. The Lowrance GPS antenna was mounted on the outside of the walkaround cabin side. Can be seen in this photo:
Reception was definitely effected by the location. The time for initial position determination would depend on the boat's compass head, and the system might briefly lose position - and then regain it - as boat heading changed. I think the cabin side just provided too much shadow to the satellite signals.
Last October we had a hard top installed, moved the antenna to the hard top, and everything works great.
I would be careful with anything that shadowed the signal path from the satellites to the GPS antenna. While the windshield glass might not be any problem, the frame - and people's bodies - might be.
Sounds like the windshield could actually degrade the performance in some situations. The extention is a decent idea. That way I could lower it on a ratchet mount when the console cover goes on. Thanx for that one!
I still wonder why the small handheld units that that people use in their cars seem to work so well and they recieve through the metal roof and or glass windshied.
I've had two center consoles with T-tops and both had the GPS mushroom antenna mount on top of the dash (electronics box) behind the plexiglass wind shield. No reception problems at all. Don't bother to rail mount it on the console if you're planning on having a cover. I also would not mount it on the side of the console as it would cause a reception shadow. You can just make out the antenna in this photo:
i have mine mounted on the dash behind the widshield. i get great reception!!!
i would hesitate on mounting it anywhere someone might grab it trying to keep there balance, or anywhere people are going to be bumping into it. you wont have any problem just mounting it behind the windshield.
good luck
capt. jim
rippin lips charters
The early bird gets the worm but the second mouse gets the cheese
Montauk Joe got the right answer. The windshield, windshield frame, peoples bodies, a canvas Bimini top, etc., will have no adverse effect on your GPS signal. Best place to mount the antenna from what you have said is atop your electronics box.
As for wiring "all those little wires which have to be connected." It sounds like you have a Lowrance unit? If so, you should have a power cable, a short cable attached to the antenna module and some accessory wires. Read your installation manual. The power cable is pretty self explanatory. The 12 inch or so cable attached to the antenna has a factory installed connector that connects to the back of the display unit. You also got an extension antenna cable that you should not need since you'll be mounting the antenna on top of the box that the unit resides in. Mount your unit in the electronics box, mount the antenna flush to the top of the electronics box (you won't need/don't need to use all of the antenna mounting parts - just silicone the antenna to the top of the electronics box - but don't forget to drill a 5/8 or so inch hole under where the antenna will go so the antenna connector will pass through - the installation manual tells you the size hole to drill for the connector to pass thru).
You can worry about "all those little wires which have to connected," later as they are accessory wires and you can decide at a later date if you want to use any of them or not.
"Peoples bodies will have no adverse affect on your GPS signal" , well people if you think that's the right answer then try it some time.
One reason why when using a handheld to always face the equator if possible as there's no sats over the poles, basically behind (through) you.
The best (ideal) antenna location is one with a FULL 360 degree view of the sky above about 5 degrees. Many (most) other setups and configurations will work but not as totally dependable or reliable due to "possible" obstructions and interference to varying degrees, depending.
However a plexiglass windscreen shouldn't have much (any) affect at all.
Mount everything except the antenna, use the long extension wire provided, turn the unit on the "satelite status page" place the antenna in all the locations you think will provide the best reception. Let the unit display which location actually provides the strongest signal. Don't hold it with your hand above the antenna because it will interfere with reception. Try to find a protected area for it. After you find the location you want then drill and mount it.
The antenna will recieve through glass, plastic and fiberglass with no problem (the case of the antenna is plastic) but metal, wood and people will interfere(put your hand over the antenna and watch the signal drop)
Mine is mounted about 12in in front of the display inside the electronics housing without using the extension cable, it receives through the fiberglass box and windshield and is protected by the housing.
The loose wires are to exchange NMEA or DGPS data with accessories.
[This message was edited by gb2052 on 03-17-03 at 06:46 AM.]
Thanx for the input guys, I think I can get the antenna mounted in a good spot now. This happens to be a Garmin 2006C, The antenna has a fairly long cable containing 8 smaller leads which is preconnected to the antenna at the other end. There is also a much heavier cable with the female plug at one end for the display and 12 small leads at the other. Some of these leads are power, some need to be connected together and some will be unused. I think I can determine which leads need to be connected together, but how to conect them? Butt connectors or bring them to a connector block?
GPS Antenna mounting question 
, well people if you think that's the right answer then try it some time.
