brought the nrf-box out to the car to see what a modern head unit would tolerate.
got about two feet of effect and figured that meant two feet of emission.
it doesn't.
effect range is where the link finally gives up.
link margin hides everything between that and where you're actually radiating.
a phone six inches from a head unit shrugs off noise that would flatten a hearing aid across the lot.
there's no hobbyist exemption and no "it's my own car."