imported post
I suggest carrying 2 at a minimum, with at least one being a covert "spy cam" type like a watch, pen, neck tie, shirt button, hat, cigarette lighter, flash light, USB drive, or any other kind that you can find that you like. Have a plan to put it into action with no one being able to tell it's a camera or that its recording. The spy cam systems have become extremely cheap on ebay. (I know, screw ebay, but I'll use them to further gun rights)
The other one of the minimum 2 I suggest is an obvious, typical recorder. This will be the one that you ask a rogue cops permission to run. If you run into bad cops, and they refuse to let you record, or worse yet take it from you, that is what the other recording system is for.
Another thing I suggest strongly is to have a cell phone with you that is set to speaker phone. If you see a cop car charging towards you, you can punch 911 into it. If you see a cop charge out of the car and draw on you or maybe act ready to and tell you to get down or put your hands up or something, you can hit the call button, and drop it on the ground. I am always ready to do this in a higher risk city, particularly when OCing on my own. If you call 911, you will have a recording with them of what the call has on it, and plus, you can say you want the help of the state police, or perhaps the Sheriff's department if you trust them and they aren't the ones messing with you. If another agency arrives, it will also give you further evidence, because of more witnesses.