[btbuildem]

I was very excited to see what the comments were going to be, but the mafia angle is a real bummer. There doesn't seem to be a way to mount a counter-measure without being detected.

A microwave generator combined with a parabolic dish? Not sure your apartment provides enough power to knock out electronic equipment with this, plus it's a super dangerous contraption, you could accidentally cook people alive from the inside out. It would also be pretty conspicuous.

I don't think a tech approach would be effective here. It's still violence (in the sense that you're forcing your will over that of others'), and they (the mafia) have a long history of being very good at violence. I'd steer away from any plays from their book.

Maybe a social engineering angle? You mention many other neighbours are affected -- perhaps band together to find a solution? Maybe target the demographic that attends the club. A social media campaign? I have no idea what the social norms are in Italy, could you organize a local protest and shame them out? Petition the don to order his underlings to cease?

I'm really sorry about your predicament, it's difficult when your home is intruded on like that. There's no easy solution here.