  Previous analyses of the space densities of extragalactic radio sources have
proceeded on the assumption of two populations: flat-spectrum and
steep-spectrum objects, compact and extended in radio structure respectively.
It is now generally believed that anisotropic radiation and relativistic
beaming effects mean that the steep-spectrum objects are the flat-spectrum
objects viewed side-on. The implication is that all previous space density
analyses start from the wrong basic premise. There are two unifying paradigms
extant for the powerful radio sources, one relating flat-spectrum QSOs and the
steep-spectrum FRII sources, the other the BL Lac objects with FRI sources. Our
new investigation of space distribution and luminosity functions takes these
two populations as a starting point in a new parametric analysis of space
densities. The present paper describes the datasets, methodology and first
results.
