Exactly is a constant legal dispute :) However, the FCC pretty unarguably has authority over use of radio spectra, especially when that use is malicious. https://en.wikipedia.org/wiki/FCC#Regulatory_powers_and_enfo... They get to determine who gets to use what spectrum, where, at what power, and for what purposes.
My point was more that poaching rhinos does not really happen in US territory, and the FCC is an American agency with no international authority that I am aware of.
I of course was being flippant, but if you want to bring reality in to the mix then your answer isn't complete. I believe you are only talking about international waters.
For example, Boumediene v. Bush establishes that the US has "complete jurisdiction and control" over Guantanamo Bay Naval Base, even though Cuba retains ultimate sovereignty. And US jurisdiction in parts of Antarctica is .. complicated. http://219mag.com/2011/03/23/u-s-government-fails-to-protect... .