Saw this question and it intriugues ,so i started thinking which hurt i might add ,and the more i answered car questions the more it puzzled me.So i rang an old friend in england who worked on and installed radar in lancaster bombers during WW2 and his answer was all of them to an extent .The blind sector increases in relation to the other issues getting worse,but he is suffering a bit with alzeimers and i had a job getting off the phone because it was like he was still their as a young man,anyway he started going off about the transmitter wires ,not a dish?? needing dropping and cleaning but make sure i have a watchout working with me to keep an eye open for stukas whilst the radar was down .If i get like that?? anyway thats what he said if its any help .Ican always pass his number over in the UK if you can get some sense out of what he says