Here’s a short story about a trick Felix showed me. When we were installing the new ground system, we were working right at the base of the towers, which were VERY HOT with RF. The two end towers, even de-tuned for daytime operation still had significant induced RF since they were only about 500ft away from the 50kW center tower! So the towers were a potential lethal shock hazard even though they were not being directly driven by the transmitter.
To “safety” the tower, there was a buried copper cable, about size “000” that had a crook in the end – we would take the crook end and hang it off the bottom of the tower to insure it was properly grounded and then safe to work around. (It messed up the daytime pattern when we did this, since the tower would no longer be properly detuned, but that’s another story).
On more than one hot summer afternoon, a typical summer thunderstorm would build in the distance and begin rumbling in. We wanted to work as long as we could, but we also wanted to be away from the towers when the lightning began to fly around. We didn’t keep a portable radio with us, but we did want to hear the weather forecast. Well, the weather forecast was always right after the news at the top of the hour, so we would watch the clock to know when the next weather forecast would be on the air.
At the right moment, Felix would un-ground the tower and hold the crook of the grounding cable close enough to the tower base to draw a small arc. The flame of the arc was modulated RF, and we could plainly “hear” the weather forecast in the flame of the ARC!!! Audio from fire!
We would then decide if lightning danger was approaching and how much longer to stay out working before the storm arrived.