Not got one to hand at present, but there used to be a small box toward the middle of the wing, where the coax was stored, permanantly attached to the wing
The main atu box was to the front of the wing, mounted through a reinforced hole with a bit hand size wing nut onto a stud in the bottom of the atu
As you can see if more than 2 nets were needed they could drop the side mount sticks in which would just take the rubber flexibase piece and the coax would be routed through the canvas and into the radio bay
These were also mounted on both wings, depending on the configuration of the radios carried, ie more than one net being used
not a series but the same position basically
This one shows the small box, and the atu would be mounted forward of this