[Steve D.]

They probably could have produced a 30" round color tube. But why? 21" roundies of the period were bulky and heavy enough. Can you imagine a 30" round color set? Just to create the proper deflection, the length of the tube and hence the size of the cabinet would take over the room. That and the shadow mask and glass envelope along with a huge high voltage section ect. would weigh a ton. Not to mention the convergence problems. A rectangular tube design was the only logical and practical solution at the time. This provided a decent size screen and a better aspect ratio.