  Observations of V404 Cyg performed with the Westerbork Synthesis Radio
Telescope at four frequencies, over the interval 1.4-8.4 GHz, have provided us
with the first broadband radio spectrum of a `quiescent' stellar mass black
hole. The measured mean flux density is of 0.35 mJy, with a spectral index
alpha=+ 0.09\pm0.19$ (such that S_nu \propto nu^{alpha}). Synchrotron emission
from an inhomogeneous partially self-absorbed outflow of plasma accounts for
the flat/inverted radio spectrum, in analogy with hard state black hole X-ray
binaries, indicating that a steady jet is being produced between a few 10^{-6}
and a few per cent of the Eddington X-ray luminosity.
