Abstract: We present the results of an experimental and numerical study of the
distributions of the imaginary and real parts, P(v) and P(u), of
Wigner's reaction K matrix for irregular, tetrahedral graphs
in the presence of an absorption. In the experiment we used microwave
graphs (networks), which were built of coaxial cables and attenuators
connected by T-joints. Distributions of the imaginary and real parts
of K matrix were obtained from the measurements and numerical
calculations of thescattering matrix $S$ of the networks, respectively.
We show that the experimental and numerical results are in good agreement
with the theoretical predictions.