Broad-band flux density variations of the extragalactic radio source 1611+343

A flux density outburst at low radio frequencies (less than about 1 GHz) has been observed in the extragalactic radio source 1611+343 (= DA 406). Observations in the period from June 1976 to September 1978 were made with several telescopes covering the frequency range from 0.325 to 15.5 GHz. The outburst appears to have been simultaneous at all observed frequencies and had a steep spectrum above 0.400 GHz. Some physical implications of these observations are discussed.