I would think you'd have to pitch this idea to the FCC from the standpoint of public safety and NOT extended range for a part 15 AM transmitter. Also, it might help to have the endorsement of an association the FCC respects. The ARRL comes to mind. Perhaps you can get them on board and they may even help you to file the petition.
But don't be surprised if the FCC, while granting the longer ground lead also wants some kind of precaution in the rule that prohibits the transmitter's signal from going beyond a certain highly limited distance. Such is the irony of a bureaucracy.
require a mov arestor in the ground lead. safety w/o radiating ground lead for elevated installs.
it takes large instantaneous voltage spike beyond what a 100mw tx can produce to close the arestor.
result? no ground lead radiation.
What about the building's power ground grid from the audio and power cables? How do you shunt the system properly? Seems like the specs of the MOV would be critical.
This upsurge (no pun intended) in ground talk has served to dredge up related matters that are actually part of the matter, as just reminded by Ken.
I've worked extensively in pro audio and remember some odd grounding problems, one of which I'll refer in particular: a Studor tape recorder had an interesting section in the manual that described a wire that provided an electrical ground as per the electrical code, but discussed the fact that having a system audio ground at the same time might cause a ground loop and the resulting hum in the audio signal. It advised making an engineering decision of whether to go with audio system ground or electric ground.
RF adds a whole additional layer to the matter, that of ground signal propagation.
i also just thought of another option. you can reduce the input power by a mW or so for every few meters above 18 inches off the ground you have the tx mounted.
they can calculate the math and allow a little gain in the numbers without too much over kill.
so they can give people an advantage of elevation while still keeping the range down.
i am sure rich could come up with a model.
I like that idea- raise height, lower power. Overall gain = zero
How about this - you pay off a tower jack to stick your battery operated transmitter and iPod on top of a 1,000 foot tower so passing airplanes can hear it.
the power to height ratio can be tweaked to allow a slight advantage to elevated installs over a ground mounted one.
they do something similar under part 15 ism rules.
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