A brief word of advice: If the FCC shows up at your door, do not let them in unless they have a search warrant or an equipment seizure order. Further, do not speak to them or volunteer any information, and do not hand over any equipment without a written legal order which must specify exactly what is to be seized. Take charge of the situation, grab a camera (still or video) and start filming them (this usually causes them great discomfort). Their chief weapon is intimidation (they may try to lean on your landlord if you are a renter - forestall this by talking to your landlord ahead of time and explain that you are engaging in 1st Amendment activities -not running a drug lab - and that he/she can not be held liable for your Free Speech activities by the FCC) and a lack of self confidence and knowledge on their intended victim's part. Enforcement policies are not consistent from district to district. Finally, do not freak out, they are only Federal geeks with badges, no guns unless they bring backup support which is rare unless they are really serious about seizing your transmitter. Do seek legal counsel and plan ahead.
Knock, knock - Legal Defense Guide