 In May 1939 the unit was transferred to a Battle , and in mid @-@ June " Stuffy " Dowding was taken on a test flight . Bowen operated the radar and made several approaches from various points . Dowding was impressed , and asked for a demonstration of the minimum range . He instructed Bowen to have the pilot hold position once they had made their closest approach on the radar scope so they could look up and see how close that really was . Bowen relates the outcome : 
