Lossless video data compression is performed in real time at the data rate of incoming real time video data in a process employing a minimum number of computational steps for each video pixel. The cover has a periphery defining an indentation therein and is formed with two pairs of tabs extending towards the base. The average release time from the traps may be longer than the period of any present RF signals, thereby effectively immobilizing the surface conduction layer, which may substantially prevent capacitance and inductance changes due to the RF signals.