The part 15 rules for intentional radiation on the AM band are reasonable if this "permission" is intended to allow an individual to transmit to his own radios at home.
The combination of "100mW to the RF final" and "3-meter vertical antenna" produces just the right signal strength for use within one's home and adjacent property.
My kitchen radio is located 7-feet from my AMT5000 Wintenna installation (the metal window frame is part of the antenna), and the radio overloads from being "too close."
To reach the kitchen radio with less signal strength a second transmitter/antenna (different frequency) is located 35-feet away.
If the FCC allowed more AM signal strength all the radios in the house would over-load and it would be necessary to locate the transmitters outdoors somewhere as far away as possible, limited by the size of the yard.
It is probably true that the FCC never intended AM part 15 to reach a distant audience, although it is not expressly forbidden, for which reason much effort goes into doing just that.
Placing the transmitter in outdoor space with ground radials achieves amazing reach.
Back in the 1950s people probably tried
to comply and many did not.
The Knight Kit Phono Oscillator sure bridged
a much greater distance than anybody anticipated,
I think.
What is great about you Carl, is that you see things
that the rest of us miss.
Bruce, DOGRADIO
Interesting observation but here there has never been any overload observed with several radios in close proximity to the antenna. The only exception is when the AVC is turned to manual and cranked up too high on the BC-1004-C. None of the other radios have switchable AVC. I don't doubt your observation and just wanted to share mine.
And Bruce, you might not remember that I measured the DC input power to the final of the KnightKit broadcaster and it was 183 milliwatts with a 10 foot wire antenna attached but there was no matching network to the antenna so there probably was little radiation. The antenna was coupled via a series capacitor to the plate of the final which certainly enhanced the radiation of harmonics.
Despite this, good range was had when this was on the air back in the '50s. The band was much quieter and there was little QRM. AM BCB DXing was a joy then. (How's that for abbrevs. ?)
Neil
I got so deeply involved with my Knight Kit back in the 1950s that I had wild thoughts...
For example, when I broadcast at 600kHz, the harmonic at 1200kHz was just as strong, and I was trying to think of a way to put separate audio on the harmonic, so that I'd have two transmitters in one!
I did not realize that my father's shortwave radio would have allowed me to hear the upper-upper harmonics.
Right about that time an FM station was testing subcarrier (SCA) transmission, and because I had no idea how that functioned, I liked to imagine that somehow I could "hide" a second transmission on top of my programming.
Now I am still trying to accomplish those same things.