Spy agencies once classified Des Ball as a "person of interest", but he was far, far more interested in understanding their shadowy secrets.

Pine Gap intelligence base in central Australia held a special fascination for him, and more than any other academic, Ball helped reveal to the public just what secrets those remote dishes and antennae plucked from the skies.

Professor Desmond Ball, in his office at the Australian National University in 2013. Credit:Rohan Thomson

He was a patriot and a democrat, believing Australians had every right to know what the alliance with the US had brought to what he called "a suitable piece of real estate" near Alice Springs in the title of his most famous book.

But Ball - who died on Wednesday after a long illness - also took a sweeping view of defence and security threats, and had a rare influence on government thinking for an outsider of officialdom.