The sun is bright, but it's not bright all over in the lower VHF/UHF ranges. The quiet sun has a mimimum radio emission at about 50 MHz and then linearly (mostl

The sun is bright, but it's not bright all over in the lower VHF/UHF ranges. The quiet sun has a mimimum radio emission at about 50 MHz and then linearly (mostly) increases up to 10 GHz (and more). So at the lower frequencies radar echos can be detected as long as there are no active flares/etc going on. http://a.superkuh.com/radio-sources.jpg http://a.superkuh.com/radio-sources.jpg Although it's emission (due to the transparence of it) is not just a disk but sometimes increases on the limb depending on frequency, http://a.superkuh.com/solar-disk_relative-brightness_vs_solar-radii.png http://a.superkuh.com/solar-disk_relative-brightness_vs_sola... Here's a diagram of how the ray paths from an Earth based radar reflect from the soft target that is the sun, http://a.superkuh.com/what-solar-radio-looks-like.jpg http://a.superkuh.com/what-solar-radio-looks-like.jpg