Re: Switch Vex Cortex 2.0 back to Vexnet
Another thing you might try is to manually re-link your Cortex and VEXnet Joysticks. We have instructions on how to do that here: http://www.education.rec.ri.cmu.edu/products/teaching_robotc_cortex/reference/VEXnet_setup_guide.pdf
The Cortex shouldn't be any more or less sensitive than the PIC radio-wise. What may be happening is that the joysticks on the Radio Transmitter are sending non-zero values, even when they're centered. This tends to happen after the Radio Transmitter has had a decent amount of use. You can adjust the trim on the joysticks to ignore some of the small non-zero values. Instructions here: http://content.vexrobotics.com/docs/inventors-guide/main-2008/06-control-06272008.pdf
The other possibility is that there is another piece of equipment nearby that is operating on the same or a very similar frequency as the Transmitter, causing interference and false values to be sent to the robot.