6 2009 Fermi Symposium, Washington, D.C., Nov. 2-5 Figure 1: continued Figure 2: VLBA spectra of sources whose spectra cannot be adequately described by the simple homoge- neous model. The spectra correspond to parsec-scale core regions. Green lines represent a power law fit. It is possible to fit a homogeneous synchrotron source model (blue curve) to the observed spectrum of 0716+714, however, a simple power law provides better (lower χ $^{2}$) fit. eConf C091122 (q) NRAO 530 image † (r) NRAO 530 spectrum † (s) 1959+650 image (t) 1959+650 spectrum (u) 2155 − 304 image (v) 2155 − 304 spectrum (w) BL Lac image (x) BL Lac spectrum (y) 2344+514 image (z) 2344+514 spectrum (a) 0716+714 spectrum (b) OJ 287 spectrum (c) 1510 − 089 spectrum (d) 3C 454.3 spectrum