2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/223129We use tetrahedral microwave networks consisting of coaxial cables and attenuators connected by T-joints to make an experimental study of Wigner's reaction K matrix for irregular graphs in the presence of absorption. From measurements of the scattering matrix S for each realization of the microwave network we obtain distributions of the imaginary and real parts of K. Our experimental results are in good agreement with theoretical predictions.12 pages, 6 figuresChaotic Dynamicstext