system
A chat on subreddit /r/NoStupidQuestions
human
Yep, very much illegal. However, there's something to consider here...

You already asked them about the whole situation with cell phone blocking. There are people who know specifically your circumstances around soon to be fatherhood. If the FCC comes knocking in the near future, they're going to be able to put two and two together and know it was you.

Wisconsin is an at-will employment state. So, as long as they find some reason that is not "He ratted us out to the FCC!", they will probably be able to fire you.

However, the big "unless" here is a very well established legal precedent for any at-will employment; no employer can ever terminate you for actions taken in contrary to company policy where the company policy is asking you to break the law. Now you're not actually jamming the cell phones, but you are aware that the law is being broken. ~~So at the very least you are an accomplice~~ *edit* you're 100% right, u/squeamish

So for the people here who are urging you to act anonymously, I'd advise you to do the exact opposite. Make sure that the company knows that you are the whistleblower. And that if they fire you as a result, they are immediately going to be in double legal hot water for FCC violations and wrongful termination. You might not want to threaten them with that outright, but clearly alluding to it would probably give you some protection.

Now if you take that approach, you're probably poisoning the well and you're going to have to polish up your resume and find something else to move on to. But they won't be able to can you right away. You've probably got at least a year lead time before they can safely find something to pin on you bullshit or not.

But I'll just say this, I remember the exact second I first heard my son cry in the delivery room. No shit, it was like I was sitting in the cockpit of the Millennium Falcon, making the jump to light speed. Certainly one of the top three happiest memories of my life. So, yeah, I hate job hunting, and I know that it can be tough out there in the work market. But, priorities, you know?
gpt
And in thinking about this a little bit more, you might not want to contact the FCC. You might want to contact a lawyer who specializes in employment law, and ask them how you can confront them and tell them to take down their cell phone jammer in such a way that if they did turn around and then fire you, you'd have an ironclad wrongful termination case. In fact, you are already in a pretty goddamn sympathetic situation to a jury, namely that you want to be able to find out when you're going to become a dad.

That way, you can go to them and tell them they need to take it down, and if they get pissy with you, you can let them know that you've already lawyered up, and if they retaliate, they're going to regret it. That way the problem is solved, and there is more of a direct corollary between your actions resulting in the company not breaking the law, and your potential wrongful termination.

Still probably need to plan on getting a new job in the following year though.