Low frequency observations of the scintillation of weak radio sources

Interplanetary scintillation observations of weak radio sources have been made at a frequency of 102.5 MHz. Sources have been chosen from the Bologna catalogue, with flux densities 0.5 Jy–4.0 Jy at 408 MHz.It has been found that the average scintillation visibility is in agreement with the results of the interferometer observations of Speed and Warwick (1978).A very wide spectral index distribution has been found for weak radio sources at low frequencies, perhaps indicating the presence of a new population of low luminosity, flat spectrum radio sources.