Superconductors application in the military

I will be grateful if somebody can explain to me how superconductors are being used here for military purposes:


and what exactly are ultrasensitive selective receivers? How are they different from normal receivers? Do they mean that they will receive a weak signal that a normal receiver won't be able to receive? And where is the superconductor being employed here? In the antenna?

Thanks

Your link isn't viewable - to me.

Mike.

This is what’s in the link.

Well the text in the attachment doesn't look anything exciting, more like typical 'made up' journalist type writing.

However, as for 'highly sensitive', at high frequencies (UHF etc.) the limiting factor is noise from the front end of the radio receiver - because of this you can greatly improve sensitivity by 'super cooling' the front end, and this is commonly done on radio telescopes for that reason.

It is mentioned here but I don't have access to the file yet.

Also, this is a massive document containing some DOD superconductivity stuff I just found (I'm currently reading it):