@zen, my reference to a 14" dish was pure speculation on my part, I have only seen reference to the 9" dish in the NIGS report, my speculation was incorrect. The term Small Ship Surveillance Radar (SSSR) is not, in my opinion, coincidental to the early name for the CF.299 programme being Small Ship Guided Weapon. Despite having been wrong before I will speculate again, a single transmitter FSR/NSR using (assuming we are correct about the square footage of the arrays) 14 - 14ft 6" arrays to provide a half sized system for frigates might have been an attractive prospect for ASRE in terms of maximising return on R&D spend and providing system and component commonality across the fleet.
@JFC Fuller
I wasn't suggesting you had really, rather I'm suggesting once they moved to such Blue Envoy like range, the very basis of the rod and dish system fell apart. Command guidance obviated the need for a 20" dish or the combined 14" separated rods and 7" dish systems.
And the result is only a need for a 9" dish, not even using the potential 14" of NIGS missile diameter available.
Possibly that 9" dish might even relate to efforts to fit SARH seekers to Red Top.....? Meaning they reused it.
However my main contention is that this combination of rods around a 14" diameter and a 7"dish is originally developed to fit into a version of Sea Slug. The small dish and rods are claimed to deliver the capability of a 20" dish. The lack of space in the nose of Sea Slug is the answer to why such a small dish. All of this being cabled back past the warhead to the avionics bay.
This would deliver Green Flax like capability but reuse the Sea Slug missiles, handling gear and even the Type 901 director. Which considering the power of the reflection needed for interferometer based guidance is ideal.
This in turn partially answers why they carried on with Sea Slug.
I think you are on to something with SSR. That the reduced NIGS setup with a limit of roughly 50nm (likely on a 1sqm target) is a stepping stone to becoming SIGS. The very range drop in radar making the giant NIGS missiles pointless. Wasn't Bristol's RP.25 aimed at a 50nm range?
But a tracking range of 50nm is implying a missile of 30nm-ish range.....is this the origin of SIGS?
Starting to think this is a very complex period and some quite precise dating of things is needed to help clarify matters.
Have to say perseverance with a 14ft rotating AESA radar would have been worth it in the long run.
But I think the area for a 62.5nm range has got to be at least 25% less of that for the full NIGS 400sqft that gives 125nm range assuming output is constant.
So 300sqft or about a square of 17.5ft each side.
While 50nm is probably needing 262sqft or 16.2ft by 16.2ft
NIGS probably explains the shift in focus on Escort Cruisers.
I think Sea Dart's guidance system being evolved was a consequence of it's origins as Sea Slug mkiii. Repackaged as 'new and unrelated'.