A system for emitting electromagnetic energy at a radio frequency into a hydrocarbon stratum of earth formation traversed by borehole includes a source having impedance matching capability, which provides electromagnetic energy at a radio frequency, and an applicator which is used to emit the RF energy into the hydrocarbon stratum. The applicator includes an outer conductor and an inner conductor that is substantially longer than the outer conductor. The outer conductor is arranged with the inner conductor in a manner so that a portion of the inner conductor is located within the outer conductor and the portion of the inner conductor not located within the outer conductor is used for emitting the RF energy when the applicator is energized by the source. An end piece affixed to the inner conductor holds a plurality of insulators in place. The insulators are of a type that should they come into contact with the inner conductor substantially no phase shift of the RF energy occurs.