Amain, Castle, and Novac are just some of the companies who have caps(capacitors) you can get for an RX. It plugs right into one of the plug-ins. Once you power up it maintains a nominal voltage so that when the RX sees power spikes it does not allow the voltage to drop to low. It is kind of like a small battery, but with instant discharging capabilities. These spikes usually only last for a split second or two so you never really see any change in your operation, but it reall does help smooth things out. Here is a link to some of the ones that I use.
http://www.amainhobbies.com/product_...tage-Protector