In this paper, we provide the laboratory tests results of a prototype DOCR. The laboratory shows that the DOCR (Digital On-Channel Repeater) has Feedback signal cancelling capability for maintaining high isolation between received and transmitting antenna as well as good output signal quality for guaranteeing more than SNR 29dB. The DOCR is installed with 20 Watts transmission power at KBS (Korean Board Casting) Yeosu site.