A standing wave barrier for at least one radio frequency cable having a cable axis has at least one metallic base web that proceeds parallel to the cable axis from a first web end to a second web end. The web ends are coupled to one another in terms of radio frequency terms via a capacitance, so that the base web and the capacitance together form a radio frequency resonant oscillator circuit. The base web and the capacitance are situated in one of two half-shells that can be connected to one another such that the radio frequency cable is clamped between them. The capacitance has an adjustable capacitor element that has a first capacitor surface and a second capacitor surface. The first capacitor surface is connected in electrically conductive fashion to the first web end, and the second capacitor surface is connected in electrically conductive fashion to the second web end. The first and the second capacitor surfaces are respectively capacitively coupled to a number of first counter-surfaces and second counter-surfaces. Adjustment of the adjustable capacitor element can be accomplished by making an electrically conductive connection between the first counter-surfaces and the second counter-surfaces.