You may need to climb the roof several times while trying to get the signal. I don't think they have moved the dish more than few mm so just put a referance marking on the post where the dish holding bracket was clamped - scratch a line on both so the allignment can be done much easier. After the marking, try rotating the dish on one side only few mm and re-checked if the result negative after the second trial then move the dish back to the referance marking point and try the other side again. I'm sure you will get it quicker than trying to find someone...