[Salavee]

Originally Posted by EZM

I don't think anyone answered this question;

Sonar = a beam shot out of your transducer to return sonar signal which, essentially, "paints a picture" of what is below you. This is most useful to find structure, drop offs, changes in depths, weed-lines and, of course, fish.

GPS / Chart = a beam shot out of your antenna, to a satellite, that tells you, exactly where you are, within a few feet. "Marking" these spots allow you to quickly return to good drop offs, underwater structure, good fishing spots and whatever you choose to "mark" on your unit. Before GPS, I was amazed at "how far off" I was compared to "where I thought I was".

GPS will improve your catch rates.

As far as good units - Lowrance and Humminbird both make excellent products.

A Lowrance HDS 5 or a 597ci HD DI Humminbird are excellent choices.

Add a $150 bucks to the Humminbird (598ci HD SI), at $899, you get side imaging as well. I would suggest the 598 is the best value in the market right now.

A GPS unit is a reciever only. It does not transmit any signals. It just recieves and interprets signals transmitted from the various GPS Satellites