366-370An analysis is conducted on the extensive AI-technique measurements made on multi frequency ionospheric absorption at Udaipur (geogr.lat. 24'6°N; geogr. long. 73'7°E) during the period July 1974-June 1977 for five working frequencies in the range 2'3-4'1 MHz. It has been found from the analysis that the diurnal variation of absorption (L)at that latitude could be represented by the relation L = A + B cosn, The calculated overall mean values of cos index (n)for total and D-region absorption are 1'20 and 1'14, respectively. Analysis for the frequency variation of absorption at this place reveals that the frequency index (m) for D-region has a decreasing trend with cos and yields an overall mean value of 1'79, Dependence of absorption on solar activity has also been investigated. Some ionospheric parameters for the lower ionosphere have also been calculated like the effective recombination coefficient, etc
