An interface board connector includes a plurality of individual conductive partition element seats. Each partition element seat includes four spring fingers that extend into apertures in a dielectric base plate of the interface assembly. Two adjacent spring fingers form a tweezers-like connector in one of the apertures that couples to a trace on a balun board contact post to form an impedance-matched extension of the balanced transmission line that is an integral part of the adjacent partition element seats. Each spring finger includes three distinct sections. A ramp section allows the balun board, when inserted, to push apart the two spring fingers and slide into place. The contact sections of two adjacent spring fingers form the electrical junction between the balanced transmission line traces on the balun board contact post and the section of balanced transmission line formed by the parallel spring sections of the two adjacent spring fingers.