  We report multifrequency measurements of scatter broadening times for nine
highly dispersed pulsars over a wide frequency range (0.6 -- 4.9 GHz). We find
the scatter broadening times to be larger than expected and to scale with
frequency with an average power-law index of $3.44\pm 0.13$, i.e. significantly
less than that expected from standard theories. Such possible discrepancies
have been predicted very recently by Cordes & Lazio.
