Will an antenna made for US television pick up foreign broadcasts?

There’s every reason to think it will. Television broadcasting in most countries tends to use most of the same frequencies. In Europe, it’s mostly UHF, but in North America, all the frequency allocations are almost identical. So if you’re within 40-50 miles of a broadcast tower located in Canada or Mexico, you’ll probably get those stations.

There’s nothing illegal about it either. There are some regulations about broadcasts intended for the US, Canada, or Mexico, but as long as everyone obeys their laws about broadcast power, there’s nothing illegal about you as the average person picking up stations that originate in another country.

Of course you probably know that if you have family in Canada. Most Canadians live within broadcast range of at least one radio or TV station from the US, and although there are strict rules intended to keep Canadians watching Canadian pay-TV and cable, there’s nothing that could or would stop them from watching US TV. Of course they don’t count in the ratings, but you sort of have to expect that.

I’m sure that the regulating agencies of each country would just love it if there were some way to actively stop signals from crossing borders, but that’s just not the way broadcasting works. Radio frequency signals keep going until they get too weak to be detected, or until they hit something they aren’t strong enough to pass through. So unless we erect a 200 foot lead wall between us and other countries, you have to expect those foreign signals are just going to keep coming over the border. But that’s ok, everyone expects them to.