A method for determining isolation status of the RF repeater is provided. A modem in the repeater registers with a base transceiver station (BTS). Uplink output levels of a donor RF transceiver are calibrated and stored in the modem. The modem is synchronized to a BTS transmission received at the donor RF transceiver and the synchronization information is provided to a server RF transceiver of the repeater. Isolation detection and measurement can then be performed between donor transmit antenna and receive server antenna of the RF repeater and the automatic gain control parameter of donor RF transceiver and server RF transceiver are adjusted based upon the isolation detection and measurement value. The isolation and detection can be implemented in a co-processor coupled to the donor and server transceivers.