Abstract: A spring contact element is soldered to the end section of a plate holder hub in a high frequency tuneable cavity. The spring contact extends outwardly transverse to the shaft's principle direction and terminates in a plurality of radially extending contact fingers inclined toward and in contact with a wall of the cavity at the end of the hub. Attachment of the spring contact electrically at the plate holder hub and consequent moving contact between the cavity wall and the spring contact member at a circumference considerably larger than that at the hub provides reduced current densities in the vicinity of the moving contact between the wall and the spring contact and consequently considerably reduced power loss at high frequencies above 100 MHz.