Saitek X52 is your problem. Mine did that all the time, and got worse the longer I used it. Stick it under a truck tire and run over it. Back up and do it again, go in house and order CH products. Problem solved 
Now now... I've had my X52 for 3+ years now and calibrated it maybe twice.. and neither time because it really needed it. Mine is rock steady all the time, and I'm not exactly easy on it.
The drawback is it uses a lot of power. I'd be willing to bet that 90+% of X52 issues are due to USB power problems, and 99+% of those would be fixed with a powered USB hub.
And I know you mentioned that you have one, but perhaps it isn't getting power from the outlet, possibly due to an outlet or inverter problem, or even something internal to the hub itself. Also make sure the wire connecting the stick to the throttle isn't half plugged in... or barely making contact.. that's been known to cause issues as well (I've heard it's a standard male to male PS/2 cord).