According to one or more embodiments, a directional filter assembly (10) comprises a multi-port filter circuit (12) for combining or separating signals in specified pass-bands and an isolated port (20) having a resistive load (22), for absorbing out-of-band signals. The assembly further includes a reflective protection device (24) configured to protect the resistive load (22) from being overpowered by out-of-band signal power, based on being configured to reflect or not reflect the out-of-band signals in dependence on the level of out-of-band signal power. In at least one embodiment, the directional filter assembly is configured as a microwave transmission assembly, such as is used for combining signals from two or more base stations, for transmission from a common antennae assembly.