"Water gets into the inside of the radome and freezes. This coats the inside with ice and the radar is severely attenuated - that is, has little penetration. Hence apparent short range."
Well there you go, I never knew that! Thanks for that. Makes you wonder why there isn't a more thorough training into practical use of WXR, for example nowhere within a/c tech manuals have I ever been able to find out the most basic information, like the cone angle, I've always had to dig it up elsewhere on tech forums.