Won't work
See Cosmic background noise vs Frequency (rises sharply as frequency reduced), Shannon's Law (Information) and Inverse Square Law. Also dish gain is related to the cube of frequency, thus 1/10th frequency gives 1/1000th gain on same size dish.
Only spectroscopic analysis is likely to give results, starlight affected by planetary transits. Radio is good only to a few light years or a bit more if someone is pointing THEIR massive array with Gigawatts of power at us.