 Another attempt to revive the RDF 1 @.@ 5 concept , today known more generally as <unk> radar , was made in March 1940 when a modified set was mounted in Bristol Blenheim <unk> . This set was tuned to the transmissions of the new Chain Home Low transmitters , dozens of which were being set up along the UK coastline . These experiments did not prove successful , with a detection range on the order of 4 miles ( 6 @.@ 4 km ) , and the concept was abandoned for good . 
