I have the Kathrein BZD bought 30 indoor antenna for DVB-T due to a test report from Stiftung Warentest here. In this test, external and internal antennas for DVB-T were tested. The Kathrein antenna was the winner for indoor antennas and also convinced me immediately. Once connected to my Comag SL25T receiver and the image was perfect! Since I live in a rather difficult reception region, was a passive rod antenna unusable. This active antenna provides a perfect signal with its current via coaxial cable power supply. During my receiver in passive rod antenna only a signal strength of max. 60% took out, I have with the Kathrein antenna at each station about 98-100% !!! So from my side an absolute buy recommendation ... !!!