Sennheiser AB 9000 Active Intelligent Antenna Booster for Digital 9000 Series Systems (A1-A8: 470 to 638 MHz)The Sennheiser AB 9000 is an active, intelligent antenna booster for the Digital 9000 Series EM 9046 receiver. It features eight highly selective bandpass filters. Each filter passes frequencies within a 24 MHz frequency window and rejects frequencies outside that range, directly blocking unwanted signals before the first active component. The frequency window can be remotely selected from the EM 9046 receiver. The built in linear RF amplifier offers