A lamp assembly in accordance with the invention includes an electrodeless bulb (14) which is symmetrical about an axis (16) and which contains a light emissive fill which emits light when the bulb is excited by a RF electrical field coupled to the fill; an electrically conductive coupler (18) comprising a plurality of turns (20) which are symmetrical about an axis of the electrically conductive coupler, the turns defining a volume (19) that at least partially contains the bulb; and a conductor (26) connected to a center portion of the electrically conductive coupler with connection of the conductor to the electrically conductive coupler providing a fixing of the coupler relative to the bulb which, when the conductor is connected to a source of RF electrical potential, conducts a RF current producing a RF electrical potential on the electrically conductive coupler that produces the RF electrical field coupled to the light emissive fill.