X波段
Three designs incorporating some of these features were studied. One was essentially an X band adaptation of the otherwise unmodified Mk. VIII, operating at 3 cm instead of 10 cm. The second was a Mk. VIII that adopted the spiral-scan technique instead of helical. The third was the AIF system being developed by Lovell. After some discussion, the X band concept was dropped; they concluded that RAF familiarity with S band equipment, along with the ability to use existing beacons, outweighed any technical advantages.