gain

I am trying to find a good and thorough explanation of "gain." I've asked Horizon and they more or less said they don't have anything. I'll take a video or a written explanation, etc. FYI, I use ar636 RX and a DX8 RX.

Am looking for any suggestions/recommendations on the 3GX itself. I'm flying my first 3GX 5.0 firmware on a CHEAP HK450 with $12 FBL conversion kit. 3S 2200 separate 2S 7.4V battery and BEC for RX and FBL+ servos. 50AMP ESC HK helidrive 3600K/V and 12 tooth pinion. All digital MG servos...