Speaking of stereo television, on a related note, let's take a look at what stations were first in stereo.
For instance, here in St. Louis, if my memory serves me right, KPLR-TV, at the time a leading independent station, became the first in the St. Louis market to broadcast in stereo sometime between late August and September of 1984. When it did so, Channel 11 adopted their own version of the "Circle 11" logo to signify their entry into stereo broadcasting. In their case, it consisted of two sticks representing the number 11 surrounded by a blue circle amid a red laser background.
In addition it should also be noted that its then sister station in Sacramento, KRBK Channel 31, also changed its logo when it began stereo transmissions that year. In that regard, the only difference was the number 31 surrounded by a purple-magenta circle amid a blue laser background.