Is my Wilson Sleek broken or do i not know how to use it?

specs call for 6ft of distance between the cradle and the antenna
because both are transmitting a signal, low power at cradle for the phone, full power at the antenna for the tower, to close together and you have interference issues, the high power boosters have even more critical requirements, like 25ft seperation

if the phone is in front you want the antenna on the roof at the end of the cable
if the antenna is in the front you want the sleek cradle in the back of the Van