  We present an updated estimate of the cosmic radio background (CRB) and the
corresponding attenuation lengths for ultra-high energy photons. This new
estimate provides associated uncertainties as a function of frequency derived
from observational constraints on key physical parameters. We also present the
expected variation in the spectrum of the CRB as a function of these
parameters, as well as accounting for the expected variation in spectral index
among the population of radio galaxies. The new estimate presented in this work
shows better agreement with observational constraints from radio source-count
measurements than previous calculations. In the energy regime where we expect
cosmogenic photons dominantly attenuated by the CRB, our calculation of the
attenuation length differs from previous estimates by a factor of up to 3,
depending on energy and the specific model for comparison. These results imply
a decrease in the expected number of cosmogenic photons with energies $\sim
10^{19}-10^{20}$ eV.
