Mark Warrick is a licensed ham operator using call sign KM6ZPO. He carries his ham radio on rides to make sure that if something goes wrong, he can have two-way communications with people that can help.
Why does this matter? Because ham radios work where cell phones don’t. There are hundreds of repeaters all throughout Southern California where Mark does his tours. These repeaters are conveniently placed in high places where they can have the greatest reach, even into many deep canyons and the farthest points of the open desert. that means Mark can communicate with people who can help just about anywhere.
Amateur Radio Ham Radio Repeater Data provided by: http://www.levinecentral.com/repeaters/google_mapping.php