Originally Posted by
Bing
I think FRS.1's radar was Blue Fox with Blue Vixen being the upgrade for the F/A2.
My understanding is that the random colour/word combination was chosen as during the war the Allies had been able to guess the role of some pieces of German equipment due to the name.
Indeed Knickerbein was the 'Crooked Leg' and then there X and Y Gerat More here. See the RV Jones link below.
https://en.wikipedia.org/wiki/Battle_of_the_Beams