Source heights of metre wavelength bursts of spectral types I and III

Direct measurements by the Culgoora radioheliograph of the apparent source heights of type I and type III bursts at the solar limb are described. The average observed height is approximately the same for type I and type III sources. The heights are somewhat larger than previous estimates. After refraction effects are removed the present results give an electron density model for the source region below 3 R with densities on the average between 8 and 10 times the values for corresponding heights in the quiet K-corona.