This is just speculation but.....
Why was it stated that a missile of 14" with rods and a 7" dish had the capability of a 20" dish?
Because it was originally intended for a mkiii Sea Slug. Why?
Because they wanted, needed SARH for ranges over 30nm.
And having put all that effort into systems to handle Sea Sea Slug it was better to upgrade the system to SARH.
Admiralty had a series of interception ranges desired against a supersonic bomber. 15nm, 30nm, 60nm, and 90nm.
It's the RAF who want Blue Envoy style 150nm.....
My guess is they started with 60nm but the threat demanded 90nm..... then government said this makes for a Bloodhound successor, work with the Army and RAF, or you lose funding.
But they want 150nm.
This means big missiles and ramjet propulsion.
But getting out, even to 90nm means command guidance. INS being expensive and you'd need to update anyway.
And getting out to 150nm means signal reflection is too low a power for the rod element of the guidance to work effectively. Leaving just the 7" dish, and it's not good enough.
So they ask the question how close can you get a Command Guided missile to the target before you need to switch over to SARH?
Answer is close enough that a 9"dish will do......
But having Centred on the 14" missile .....
It's all a mess. Conflicting needs and technology.
This would be partially proven by the date of the 9" seeker dish.
