The brown wire when connected to ground reduces output of the 857D to 20 watts automatically.
KA2HPG
I believe that the ATAS-120 and the FT-857 both need to be grounded to the same potential.? ?There is a 3rd, brown wire for the power connector on the FT-857 which, if I recall, serves the purpose to provide control to the ATAS-120. 73 KA0KAF Virus-free.