survey-in mode in TMODE 3 configuration settings in ardusimple RTK2B base station

for base station board, there are three options in TMODE 3 window, in option fix mode we need to fill in the absolute coordinates again & again when we change base station location. I do not need absolute positioning. My work is only relative positioning of rover w.r.t. base station. If I choose survey-in mode then RTCM 1005 message disappears which is always seen if I choose fix coordinate mode instead. My purpose is that I need not fill in the coordinates again & again when I move  the base station receiver position from one place to another( the receiver must take new location coordinates automatically after 3-4 minutes survey ) , also RTCM 1005 message be seen always ( I think if it is not seen then fix RTK not possible ? ). If I use survey-in mode then what values to be kept for time & accuracy for this mode ( I need relative positioning only).