An automatic data collection system tracks medical articles by providing a robust electromagnetic (EM) field within an enclosure in which the articles are stored. Respective data carriers, such as RFID tags, attached to each medical article respond to the EM field by transmitting unique data identified with each medical article. The use of probes for injecting the EM field into the enclosure results in a greater likelihood of activation of the tags and greater accuracy in detecting and tracking medical articles.