Abstract: Tuning method for a combiner filter (2) in an antenna (3) near system for base station equipment is disclosed. Transmitted signals related to the combiner filter are compared with each other. A spectral analysis of each of the transmitted signals is performed. The spectral analysis results regarding magnitudes and/or phases of the signals are compared. The combiner filter (2) is tuned based on the analysis in an iteration procedure until the combiner filter is in accordance with predetermined conditions.

Abstract: The present invention relates to an arrangement in a cavity filter for tuning the frequency relationship of the filter or its coupling coefficient factor. The arrangement includes a self-locking screw that can be fitted in the filter cavity, for instance in the center conductor, in the filter lid, or in some suitable place in the filter chassis. Tuning is effected by adjusting the position of the screw in relation to the center conductor or lid of the cavity filter. The screw can be made of metallic segments embedded in plastic, or made completely of metal, and provided with a radially through-penetrating slot. At least one part of the screw has a cross-sectional area whose extension perpendicular to the through-penetrating slot is slightly greater than in a direction along said slot.