A complete sample of Northern Hemisphere active galactic nuclei - Differences in flux and spectra at high radio frequencies

We present two-epoch 22 and 37 GHz flux measurements of a complete 1 Jy sample of flat-spectrum extragalactic radio sources. The spectral and variability properties of quasars and blazars in our sample are similar. Radio galaxies, which have steeper cm-to-mm spectra, are the only sources which can be identified solely on the basis of their radio continuum properties. Surprisingly, among the flat-spectrum sources the BL Lacs and low polarization quasars with the steepest spectra seem to be the most variable ones. The implications of these results for orientation- dependent unified models for active galaxies are discussed.