ELECTRONIC MARKERS WITH PREDETERMINED SPACING

摘要

A marked conduit allowing electronic location of the conduit after burial, having a plurality of electronic markers spaced thereon at predetermined intervals. The distance between the markers encodes information about the buried conduit. The markers are preferably passive circuits tuned to a specific frequency. The markers may be oriented in a predetermined pattern to encode additional information, and may be attached to the outer or inner surface of the conduit, or imbedded in the wall of the conduit.