Total posts : 45366
When I wrote about transmitter “efficiency” in the last few posts, I was considering the load to be mostly ground resistance. The 46 ohm load resistor I was using for testing was intended to represent what I consider to be typical ground resistance. I mentioned a couple of posts back that the radiation resistance is orders of magnitude smaller than the ground resistance. So, the “efficiency” I have been writing about is how effectively the limited input power to the transmitter performs the useless task of heating up the earth. However, the more power the ground gets (and wastes), the more power is applied to the tiny radiation resistance. This is “trickle-down” electronics!
While a short antenna hardly radiates at all, it has an intense near field which decreases rapidly as the distance from the antenna increases. The intense near field is produced because the current that is applied to the load (the ground resistance) passes through the high reactance of the antenna capacitance.
In the usual Part 15 AM transmitter circuit, the high voltage that is at the antenna is only at the antenna and across the loading coil, but not at the electronic components. So, in the usual transmitter design, there is no problem with voltage breakdown. However, what Wenzel must have been considering, but did not describe, was a way to directly apply high voltage to the antenna without generating this needed high voltage using an antenna tuner.