Radar Dish
 

Anyone know why some rotating primary radar dishes have a fin at the back?

Cheers,

Bigbob.

Don't know for sure - never thought about it before - but I would guess it's something to do with reducing or balancing the effects of wind on rotation of the antenna.

I don't know for sure either. Spitoon's theory that it's to balance aerodynamic forces sounds reasonable. I'd always thought (guessed) that it was used as a counterweight.