  We describe in detail our characterization of the compact radio source
population in 140 GHz Bolocam observations of a set of 45 massive galaxy
clusters. We use a combination of 1.4 and 30 GHz data to select a total of 28
probable cluster-member radio galaxies and also to predict their 140 GHz flux
densities. All of these galaxies are steep-spectrum radio sources and they are
found preferentially in the cool-core clusters within our sample. In
particular, 11 of the 12 brightest cluster member radio sources are associated
with cool-core systems. Although none of the individual galaxies are robustly
detected in the Bolocam data, the ensemble-average flux density at 140 GHz is
consistent with, but slightly lower than, the extrapolation from lower
frequencies assuming a constant spectral index. In addition, our data indicate
an intrinsic scatter of 30 percent around the power-law extrapolated flux
densities at 140 GHz, although our data do not tightly constrain this scatter.
For our cluster sample, which is composed of high-mass and moderate-redshift
systems, we find that the maximum fractional change in the Sunyaev-Zel'dovich
signal integrated over any single cluster due to the presence of these radio
sources is 20 percent, and only 1/4 of the clusters show a fractional change of
more than 1 percent. The amount of contamination is strongly dependent on
cluster morphology, and nearly all of the clusters with more than 1 percent
contamination are cool-core systems. This result indicates that radio
contamination is not significant compared to current noise levels in 140 GHz
images of massive clusters and is in good agreement with the level of radio
contamination found in previous results based on lower frequency data or
simulations.
