I was not suggesting using an entire neon sign or vapor lamp as an
antenna. I was pointing out 'the presence of a tiny drop of mercury' is
required for these devices to work. A catalyst perhaps?

Therefore, let's say our antenna was a piece of wire or metal tubing was
inside another non-metallic tube, and a small amount of mercury was also
in the tube. Would the mercury have a desirable effect? Remember, we're
not talking about tremendous amounts of power here. Your typical 4'
fluorescent tube is a 32 to 40 watt device, and there are much lower
output tubes as well. The primary excitation inside the tube is due to
high voltage, not high current.

So, it may not be too far fetched to build a few designs and see what
performance is observed.