  Recent measurements of cosmic ray electron energy spectra suggest that above
10 GeV there may be deviations from a single power law spectrum. There are
hints (ATIC) for a bump occurring between 100 GeV and 1TeV, meaning that there
might be more high energy electrons than expected. Whether these electrons are
produced within pulsar magnetospheres, or due to Dark Matter annihilation or
decay, this is still matter of debate. Understanding the nature of these ultra
high energy particles is a difficult task that can be fulfilled using all the
available astrophysical observables. We investigate how different energy
spectra produce different observable manifestations in the
radio/microwave/mm-wave domain, where corresponding deviations from a
synchrotron power law could appear. We raise the question around the
detectability of these possible radio spectral features, which may be
interesting for a wide scientific community including astrophysicists and
scientists working on foregrounds removal for CMB experiments.
