TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Components: The filter apparatus further comprises a tag reader (124) in electrical communication with the antenna, with the tag reader being positioned in the wet or dry portion; a filter cartridge including filter media and an RF tag connected to the filter media. The antenna includes a conductor in electrical communication with a connector (137) that is for electrically connecting the antenna to a tag reader remote from the filter conduit arrangement. It is positioned on the axis of filter cartridge, when the filter conduit arrangement is engaged by the filter cartridge. The antenna conductor is symmetrical with respect to the axis of the filter cartridge. It includes winding wrapped around the circumference or around a center point on wall of the tubular portion. The filter conduit arrangement has a wet portion and a dry portion, where the antenna being positioned in the wet portion. It has an interior and an exterior and the tag reader is positioned exterior to the filter conduit arrangement. It engages a filter cartridge. It includes a tubular portion projecting into the center volume, where the tubular portion defines a conduit and the antenna conductor is positioned within the conduit. The tag reader is located remotely from the filter conduit arrangement. The filter cartridge defines an axis and the antenna conductor is asymmetrical w.r.t the axis. It engages the filter conduit arrangement include a key arrangement to orientate the filter cartridge w.r.t the filter conduit arrangement. The radio frequency (RF) tag is positioned to directly oppose the antenna conductor. It is positioned on central axis of the RF tag. A portion of the filter conduit arrangement is formed with plastic and the antenna conductor is molded into the plastic. No metal is positioned between the RF tag and the antenna conductor. The antenna conductor includes windings, preferably more than 20 windings.Preferred Process: Exciting an antenna includes radiating an electromagnetic field (EMF) from the antenna to an RF tag. Positioning a filter cartridge proximal to a filter conduit arrangement includes positioning the filter cartridge so that the RF tag directly opposes the antenna, and positioning the RF tag so that no metal is positioned between the RF tag and the antenna.