Abstract: The present invention describes a method and apparatus for a high frequency switching gas discharge tube supply which suppresses or eliminates the "bubble effect" in gas discharge tubes containing neon or argon-mercury gas or other gases and which eliminates the migration of mercury or other migratory gases toward one electrode over time. To prevent mercury migration to one electrode over time within an argon-mercury gas discharge tube, a line frequency bias voltage is induced on the high frequency, high excitation voltage resulting in a gas discharge tube display which is uniform in intensity of light over the length of the tube.