external antenna location

[Big Jeff]

I am adding a external antenna and I want to make sure it is in the best spot to get a good signal? I have a 95 crestliner sportfish nad I run my ducers on the drivers side. My thoughts are to mount it to the gunnel. The very back corner of the gunnel is the only spot i have, there is a light pole jack right infront of it and a clet infront of that.

Any other thoghts on where you would mount it?

[PerchJerker]

The location you described sounds good to me, as long as it won't interfere with your travel cover.

I've always thought they should be mounted where they get the best view of the sky and the best signal. A lot of times this is on the gunnel right in front of the console, or on the bow plate.

Lots of guys like to have their puck mounted close to their transducer, the theory being that the gps signal and the depth reading from the transducer and the position on the map card will all be in sync. In theory it makes sense, from a practical on-the-water-make-a-difference perspective I personally think they're splitting hairs.

If you have a good location close to your transducer then go for it, if not pick the best location to get a clear signal.

[h8go4s]

  PerchJerker said:

The location you described sounds good to me, as long as it won't interfere with your travel cover.

I've always thought they should be mounted where they get the best view of the sky and the best signal. A lot of times this is on the gunnel right in front of the console, or on the bow plate.

Lots of guys like to have their puck mounted close to their transducer, the theory being that the gps signal and the depth reading from the transducer and the position on the map card will all be in sync. In theory it makes sense, from a practical on-the-water-make-a-difference perspective I personally think they're splitting hairs.

If you have a good location close to your transducer then go for it, if not pick the best location to get a clear signal.

I disagree. It's not splitting hairs. Why would I pay hundreds of dollars for a system and then choose to compromise its accuracy? The GPS antenna should always be located as close to the transducer as possible.

[PerchJerker]

  h8go4s said:

I disagree. It's not splitting hairs. Why would I pay hundreds of dollars for a system and then choose to compromise its accuracy? The GPS antenna should always be located as close to the transducer as possible.

It's the difference between what happens in THEORY and what happens out on the water in the real world.

A 15-20 foot difference in the location of the gps antenna is less than the error that you're going to consistently get with the accuracy of your gps, the accuracy of your map card, and your ability to control your boat. The top tech guys at Lowrance and Humminbird admit this ..... this equipment and boat control are just not accurate enough to worry about a few feet here and there. The sales guys may not sell it that way, but the tech guys and support guys will myth-bust it.

Some guys like to sweat these kinds of minor details, some guys choose not to worry about them. This is one that I don't worry about.

Even if you don't buy the facts about the accuracy and the boat control and you have to have your gps puck over your transom transducer .....

What's going to happen when you're using your bowmount trolling motor with built-in transducer? Now your transducer is 15-20 feet off from your gps puck and map card.

Even worse, what's going to happen when you mark a waypoint with your gps puck near the transom transducer and now you try to hold on that waypoint with your i-Pilot? Now you're trying to hold on a spot that's 15-20 feet away from the spot you selected in the first place.

Or even worse than that, what if your high definition map card is not exactly accurate for your spot? I think we've all seen that.

The bottom line is that the accuracy of the gps, the accuracy of the map card, and our abilities to control our boats are not good enough to fret over getting your gps puck mounted right over your transom transducer. If you have a good moutning location there then go for it, but in my opinion you're far better off making sure your gps antenna is in a good location for a clear view of the sky.

[h8go4s]

"A 15-20 foot difference in the location of the gps antenna is less than the error that you're going to consistently get with the accuracy of your gps, the accuracy of your map card, and your ability to control your boat."

Wow. Add all that up and I could be a hundred feet off from where I want to be! Sounds like an anti-commercial for I-pilot link. Follow the contour.....well, sort of. In my experience, with a HB 898 and Lakemaster 1-foot contours, you're exaggerating. I grant that all the components of boat control have inaccuracies that vary with circumstances. So why CHOOSE to add MORE INACCURACY when you install the GPS antenna? If your attitude is "close enough for government work", maybe you should let your customers know that before you rig their boats.

"What's going to happen when you're using your bowmount trolling motor with built-in transducer? Now your transducer is 15-20 feet off from your gps puck and map card."

That's an easy fix, and lots of people do it because they want the BEST ACCURACY THEY CAN GET. They add GPS and sonar at the bow.

"If you have a good moutning location there then go for it, but in my opinion you're far better off making sure your gps antenna is in a good location for a clear view of the sky."

Why compromise? With all the stuff people have hanging on their transoms nowadays, like trolling motors, Talon systems, 360 imaging systems, what's so difficult about fabricating a stalk to mount the GPS antenna at the height of the outboard? Search this HB forum for photos of ways to do this.

http://forums.sideimagingsoft.com/index.php?action=forum

As for a clear view of the sky, I get a GPS fix in my garage, in a townhouse where the garage is surrounded by living space on three sides. Granted, not the most stable position lock, but it does see several satellites.

[delcecchi]

To add one thing. The WAAS correction signals are broadcast from a couple of satellites only. Here in the middle of the country they seem to be fairly low on the horizon. If you are not picking up one of the WAAS satellites your GPS accuracy will be degraded.

So you can still be picking up a position and not getting the best accuracy.