The Radio Spectra of Sources in the Fourth Cambridge Catalogue

Measurements made at 38, 178, 617 and 1417 Mc/s have been combined to examine statistically the spectral properties of virtually all sources whose quoted flux densities in the Fourth Cambridge Catalogue are greater than, or equal to, 5 × 10 ⁻²⁶ watts m ⁻² (c/s) ⁻¹ , and which lie between 20° and 40° declination.