When it was built in 1936 it was called the Naval Reserve Armory. The building was actually one of Franklin Roosevelt’s Works Projects. It wasn't re-named for Captain Ola F. Heslar until 1965. (He died in 1970 so at least he was aware of the honor.) He was the Commander of the Indianapolis Naval Reserves from 1922 until the start of WWII. The Armory was also a secure location for Navy Generals and Admirals to meet to plan their military campaigns far away from the heavily surveilled coastal areas.
That radio town turns out to be for the facilities' then primary function as the Navy’s national communications training
center in WWII. It turned out more than a thousand trainees every three
months. They trained radiomen and yeoman recruits on a simulated navigation
bridge complete with actual signal hoists, lights, telephones,
boiler room, radioshack, galley, and more. More here.
It's worth noting that Heslar himself also served as a radioman.