@MTShaw and
@Good2Golf , I think this was posted a long time ago but page 30 of this edition of Canadian Naval Review is pretty good for SPY-7 information.
https://navalreview.ca/wp-content/uploads/CNR_pdf_full/cnr_vol15_3.pdf
The TRM's (transmitter receiver modules) called sub-arrays are small and built directly into the backside of the radar array's surface. These subarrays are modular and can be easily removed for repair (30 seconds in some cases).
The Spy 6 sub-arrays are 2'x2'x2' and the Spy 7 sub-arrays are shoebox sized (so significantly smaller) and arranged perpendicular to the surface (the small face of the shoebox points outwards).
Adding more subarrays increases the range and sensitivity of the radar (identical to the Spy 6). Both radars can replace a sub-array without shutting down the other ones.
The capability is that CSC will get SPY-1D ranges from a much smaller footprint.