Good Info SWWASAS on the electronics side. Talmadge Mooseman, on the subject of security. I only carry something for close in defense. Probably should have a fire arm and if I was in BIG BEAR country I would. But here in Maine there are only Black Bears even though I do not say that lightly. I just use common sense on trails and make a lot of noise when bushwhacking and try to never get myself into a situation where visibility is less than 20 yards.
And now for the fun part. At the campsite, whether alone or not, I pay out a good sized circle of black thread, say 100' in diameter, and hang small cowbells over places where there are rocks. I run it consistently at about 2 ft. off the ground all the way round. In a nutshell, string gets broken, bells drop, and the rest you can guess. If the area around the camp is dense I run the string in segments across the more open accesses and tie a bell to each. The system is cheap and effective, allows small animals through unhindered and so only sounds off when something LARGER than a raccoon or small coywolf come through. The benefit? I sleep very well. I leave the system intact when away from camp and so always know if I've had a visitor. You'd be surprised how far away one can hear the bells drop onto the rocks. The entire set up stores in a small cloth bag.