Fire is a powerful signaling tool and one that takes advance preparation. Three fire bases should be prepared in a triangle 30 to 50 feet apart. This creates a V which means require assistance. The fire at the apex of your V should be your camp fire which will be burning at all times. The fire bases on the points of the V will be prepared but not burning. When a search aircraft (a single engine aircraft or a helicopter) enters your area, touch off your other two fire bases. This will give you a triangle of fire which will distinguish your plea for help from other fires that may be in the vicinity that you know nothing about. The same applies to smoking fires. Build your fire bases, on the points, with extremely dry tinder on the bottom. On top of that put lots of dry kindling, and on top of that pile green vegetation. When a search aircraft enters your area pile green material on top of your existing fire, and torch off you other two fire bases. This will give you the triangle of smoke.