 Complete the following phrase:  Offshore and nearby, are concrete and brick relics of Indicator Loop  Controlled Mining Station number 285, constructed by the Royal Australian Navy during world war two. Mines were laid in this area. An indicator loop was an electrically charged cable, used to indicate shipping movements. In this case, the cable was situated from Hungry Beach to Juno Point at Patonga, two kilometres distant on the opposite side of the Hawkesbury River. The cable was used in the detection of 