  An issue which has attracted increasing attention in contemporary researches
are Kirkwood--Dirac quasiprobabilities. List of their use includes many
questions of quantum physics. Applications of complex tight frames in quantum
information science were recently demonstrated. It is shown in this paper that
quasiprobabilities naturally appear in the context of unravelings of a quantum
channel. Using vectors of the given tight frame to build principal Kraus
operators generates quasiprobabilities with interesting properties. For an
equiangular tight frame, we characterize the Hilbert--Schmidt and spectral
norms of the matrix consisted of quasiprobabilities. Hence, novel uncertainty
relations in terms of R\'{e}nyi and Tsallis entropies are obtained. New
inequalities for characterizing the location of eigenvalues are derived. They
give an alternative to estimating on the base of Ger\v{s}gorin's theorem. A
utility of the presented inequalities is exemplified with symmetric
informationally complete measurement in dimension two.
