  We investigate the populations and evolution of normal and active galaxies by
extending the infrared source count model of Rowan-Robinson (2001) into the
radio. The FIR-radio correlation is used to extend the SEDs to the radio region
and it is assumed that there are two distinct populations of quasar: radio loud
and radio quiet. It is found that the radio luminosity function and source
count data are best fit when the fraction of quasars that are radio loud is
allowed to increase with optical luminosity. This implications for this are
discussed, as are the possible causes for the variation in radio loud fraction.
