Navigation and Seamanship

6.3.1.1. The Decca Chain

The Decca Chain

A Decca chain consists a master station controlling the phase of three slaves, which are positioned about 120 degrees apart, at a radius of 60 to 100 miles from the master. This network will cover the maximum possible area.

· Master Station normally transmitting signal within the range of 84 - 86 kHz,

· Red Slave Station transmitting a “ 8f ” signal in the 112 - 115 kHz ,

· Green Slave transmitting a “ 9f ” signal in the 126 - 129 kHz ,

· Purple Slave transmitting a “ 5f ” signal in the 70 - 72 kHz .