What is static discharging noise and what is its effect on radio communications?
The noise is created by sparks caused by static electricity. As the aircraft flies through the air, it picks up electrons from the air molecules. This extra charge will want to flow back into the air to equalize the charge. Small gaps in the conductive path on the aircraft will cause sparks to form. These sparks cause noise on radio frequencies, which can be picked up by the aircraft radios.
The static sparks will cause noise on the aircraft radios, sometimes a crackling sound. 
Aircraft use static wicks on trailing edges to allow the charge to equalize. If components are electrically bonded well, static electricity should not be noticeable, other than under certain circumstances. The wicks are fixed and not telescopic but of course can be removed if replacement is needed.