Based on the interaction between r-f field and the electrons furnished from an auxiliary d-c discharge, a gas discharge switch has been developed for controlling low level 10 cm-band signals by modifying the keep-alive electrode of a cell type 1827 TR tube. It has been found that the attenuation was considerably increased when the top of the keep-alive electrode was off-center and close to the side of the lower hollow cylindrical post. Nitrogen or argon at a pressure of about 4 mm Hg was found to be appropriate as a gas filling for such a switch. An attenuation of more than 30 db was obtained from a tube having a keep-alive depth of 0.0 mm and a distance of 0.7 mm from the keep-alive to lowcr-hollow-cone. The gas filling was nitrogen at 4 mm Hg, and the keep-alive current was 1 ma with a d-e gap voltage of about 450 volts. Such a switch has a very long life, as there was no appreciable change in the tube behavior alter operating continuously for several hundred hours.