As a teen in the early 80s I played with many FM transmitter kits, but liked one in particular (can't recall the brand, possibly Amtroncraft) which used a MRF237 and was rated 5W. I didn't have a FM antenna nor a VHF SWR meter to make one and test it, but I thought: "27*4=108, my mobile CB antenna should resonate...". So I put that CB antenna on the balcony, turned on the TX with an audio oscillator as input then called a friend living roughly 2Km away and his home on the other side of the building (no line of sight) asking him to tune his FM radio to my tx frequency, and he got the beep loud and clear. I couldn't believe that, I just had to hear it with my own ears, but I thought the beep would draw too much attention, so I connected the input to the stereo, put on a record (by KISS if memory serves), then went out and as fast as I could with my boombox walked to my friend's house and further; At some point the 1st side of the record ended so I was left with the carrier alone, but that was a success. I had too much fear of operating it however; the seventies were gone, piracy was being taken very seriously and our equivalent of the FCC, then my father, would spank my ass badly If I was caught, so after a few other tests I put that transmitter in a drawer and pretty much forgot about it.

You are right! I actually grew up in Canada and the Ramsay kit shipped from Rochester NY if I remember correctly. 1 Watt was very clearly labeled for Export Only, although still not legal in Canada.

I believe they do still sell the 1watt through distributors (I guess downloading the compliance risk?), at least they did 5 or 6 years ago last I looked.