I have a HDS Gen 2 Touch. Been using the built in GPS, marking waypoints, etc. Was wondering if the external antenna would give me more precise readings? The Point 1 or LGC-4000? The only thing I can find is that the update / refresh rate is much faster. I can't find any capability comparison between the built in unit, and the external antenna's.... what are the differences / benefits?

Thanks for any input.

The point 1 is a heading sensor (so your graph won't spin in circles while sitting still). Now if you put your point 1 above your transducer, then it will be more accurate on the wypts.

Mount the Point 1 in the rear of your boat close to your transducer and it will make your waypoints much more precise. People will tell you not to mount it near the motor and you can ignore them. It works just fine. I have mine mounted on my console on my current boat only because my rear hatches did not leave me any room to mount it in the back of the boat again. My waypoints are about 7' off by doing mounting it on the console.