 The antenna array of the original Mk . IV was limited by practical factors to be somewhat shorter than the 75 cm that would be ideal for their 1 @.@ 5 m signals . Lichtenstein operated at 75 cm , making the Mk . IV 's antennas almost perfectly suited to pick them up . Sending the signals through the existing motorized switch to a new receiver tuned to the Lichtenstein 's frequency produced a display very similar to the one created by the Mk . IV 's own transmissions . However , the signal no longer had to travel from the RAF fighter and back again ; instead , the signals would only have to travel from the German aircraft to the fighter . According to the radar equation this makes the system eight times as sensitive , and the system displayed its ability to track enemy fighters at ranges as great as 50 miles ( 80 km ) . 
