  The reciprocity approach is a powerful method to determine the expected
signal power of axion haloscopes in a model-independent way. Especially for
open and broadband setups like the MADMAX dielectric haloscope the sensitivity
to the axion field is difficult to calibrate since they do not allow discrete
eigenmode analysis and are optically too large to fully simulate. The central
idea of the reciprocity approach is to measure a reflection-induced test field
in the setup instead of trying to simulate the axion-induced field. In this
article, the reciprocity approach is used to determine the expected signal
power of a dish antenna and a minimal dielectric haloscope directly from
measurements. The results match expectations from simulation but also include
important systematic effects that are too difficult to simulate. In particular,
the effect of antenna standing waves and higher order mode perturbations can be
quantified for the first time in a dielectric haloscope.
