Total posts : 45366
I guess the short answer to your last question is – they might. Because they consider the balcony to be part of the ground.
But in that case, you would be better off to use something like a Talking House or Talking Sign transmitter. Both are grounded to the power outlet (via the neutral, I believe) and they are both FCC certified for use in that fashion. String the wire antenna up vertically on that balcony, and go for it.
Now, if you use the ATU with the Talking House, that might be another matter. I believe that the Talking House with ATU is certified for use with the ATU being a meter off the ground, which you obviously can’t do high up in an apartment. There has been lots of discussion here whether or not an elevated ATU would be legal, even if you didn’t ground it (if you do ground it, you run into the same problem with other elevated installs, in that the length of the ground + antenna would be greater than 3 meters or 10 feet).
It’s really up to the FCC inspector to determine whether your installation is legal or not if you are so unfortunate as to get the visit. As you can see, even a certified transmitter can be installed illegally.