The high pitched frequecy comes from the power Fets. When you get a little older your hearing at this frequency will fail, and you will be unaware of it!!!!!!!!!!!!. Seriously I was able to improve this by keeping the motor leads very short, and placing the RX 18 close to the motors. I did this on the JAGD, and it did improve, but I don't think you can eliminate it. It seems worse when the stick is just off of neutral, and levels out as the tank goes into motion.