HDTV started in... 1949. That's when French TV adopted a 819 -line standard, in black and white, in replacement of the early 441-line standard. That was still in use when I was a kid but was progressively dropped in the 70-early 80's in favor of the 625-line standard that used SECAM color. We were happy to settle for lower resolution but in color
. The last 819 transmitters were shutdown in 1983.
As far as I know the 819-line standard was used by the first national French channel (currently named TF1), by the French-language Belgian TV, by Télé Luxembourg and by Tele Monte-Carlo.
The next HDTV broadcast that I can think of was the MUSE standard in Japan in the late 80's, followed by some experimental HDMAC transmission for the 1992 Winter Olympics in Albertville, France and the Barcelona summer games. That standard was abandoned in 1993 in favor of DVB. I had the opportunity to see a public demo of HDMAC during the winter games. it was impressive but maybe not as much as I expected.
I remember talks of a 1050 standard for North America but i'm not sure if that was ever used.
about the antennas, Mike is absolutely correct, it's all marketing BS. There are good antennas, there are bad antennas, but they don't care much about the modulation being used...