None of the US signals that reach Montreal do so very cleanly, there is a good deal of shadowing that keeps any of them from reaching all of the Montreal metro with a usable signal. The largest share for any of the US rimshots was a 2.2 (among English language speakers) by WYUL/Chateagay, NY (now K-Love WQLR) in the early 2000s.
The Martz signals that tried to target Montreal were going after fringe coverage to say the least. That might’ve been more viable in Canada because even the larger markets used to have fewer stations, and fewer opportunities for interference, than similar sized markets here have had. Problem is, who would strain to listen to a fringe station today? English speakers in Montreal might’ve been interested in the concept 30 years ago, but no reason to put up an outdoor antenna or even buy a dipole today. The target audience can get what it wants via smartphone without any additional effort and without attempting to bend the laws of physics.
Canada's Tim Martz and his company, Martz Communications, ran a bunch of American-based border blaster stations that targeted Brockville, Cornwall, Ottawa and Montreal. I think he also tried to target Windsor with a couple of Detroit translators fed by WGPR's HD subchannels, but if I recall correctly, the effort failed miserably.
I don’t remember him targeting Windsor with those Detroit area translators and the WGPR multicast channels, but Martz did indeed run a translator network in the area that failed miserably. Seemed like he had a rock station and a smooth jazz station. The smooth jazz station interfered with WIOT, which had an audience in some of the Detroit suburbs. I can’t remember if the rock station got similar complaints, but WIOT's gripe was the end of the smooth jazz station. Martz actually had plans to sandwich translators into multiple markets and originate programming using HD multicast channels, but he gave up the effort after Detroit failed. Can’t remember all the markets he was planning to target, but Memphis was one of them.