Seventy-five years ago this month, the March 1944 issue of Radio Craft magazine contained this interesting idea for using a burnt out fluorescent tube as a radio detector.  Even though the filament is open, current can still flow from one end to the other through the ionized gas, and apparently it can rectify.

The magazine also showed how the tube could be used as an audio oscillator, as shown in the diagram below.

Even though there were wartime parts shortages, the experimenter could probably get his hands on a burnt out lamp.