Servo jitter anyway to eliminate it?

I'm running on a arduino mega, spektrum receiver and a 9252 futaba digital servo.

I have a input from a receiver and an output to a servo and simply take the input from the receiver and write it directly to the servo.

my problem is that when i am not touching the sticks on the radio the read from the input pin jitters quite a lot. I've tried the Servo.h and the Servotimer2.h library both have the same charactaristic jitter. I can by adding some samples and taking a mean value and the adding it to the servo output remove alot of the jitter but that slows the servo considerably. Is there anyway to tune the input values on the hardware or how has this been countered before or am i just stretching the limits of the precision the board can handle? Since when i add the servo to the channel on the receiver itself it does not jitter at all, this is why i do beleive the signal is precise but perhaps getting read wrong.

I might have left out important information, let me know if you need more information.

Test 1: feeding a posistion directly to the servo. no movement or jitter. you can hear a small jitter every other second, but you can't see it. Test 2: putting the servo directly into the spektrum receiver no jitter no noise what so ever.

So i'm looking at something to do with how the arduino reads/interpets the signal, perhaps the protocol is of with it's pulse signals, is there anyway to verify this? oscilloscope? Any input is appreciated.

Can you post a wiring diagram and your code?