HI SUWANDI,
IF YOU TALK IN TERM OF M/W IN THE CASE SPACE DIVERSITY ONLY THE MAIN ANTENNA TRANSMISTS SO THERE IS NO QUESTION ON TRX LEVEL OF DIVERSITY ANTENNA
well this problem mainly occur due to MHA . So in order to make it correct all u need to do is to check your connectors at ANTenna and MHA end . suppose you tried all and still the ALaram is not going than change the RX and Diversity cable ( interchage) i really hope this will work in all case .