There is an Excellent Book by a guy named "Ferguson" on GPS. As well a Good Few Other Good to Excellent Books on GPS or Related Topics. Here in America, Quality Bookstores such as the Larger Borders or Barnes and Noble are a Best Source. I Don't know how such a Book Acquisition system may be in your Country.

Sorry that I Don't know More on Ferguson right now than his Surname, -but I can Find such Out, along with the Title of his Book, Etc. And Post Back with that Shortly.

I Have Read / Soaked Up a Lot of What is in his Book though! Again it's Comprehensive and Excellent! I can Only Highly Recommend It!

Be Aware, as you may Already be, -that things like Forest Leaf Cover, Canyon Walls, and Many Other Factors such as he and Others Mention in such Books, -Can and Does Totally Interfere, with your GPS Efforts, Out There in the Field! [color:"black"] [/color] [email]Ebakeev[/email]
_________________________
"No Substitute for Victory!"and"You Can't be a Beacon if your Light Don't Shine!"-Gen. Douglass MacArthur and Donna Fargo.