That's a lot of money for a plastic box housing and a few extra wires. http://www.amazon.com/exec/obidos/tg/detail/-/B001O9X9EU/ref=ord_cart_shr?_encoding=UTF8&m=A2LM6ZPY06LT1N&v=glance
Not only that -- you don't need height unless you're blocked by boats in a marina -- you have line of sight or you don't.