it seems like on the gradient background there's some noise. Is that really the case?
Are you talking about the bitrot degredation on the background? That's a common problem with the 4000s now that they're getting so old. However, as originally designed, the background was supposed to be a smooth gradient (as smooth as that technology would allow). The best way to see the background other than just as a frame at the edges of the screen was on the "Almanac" page, where it was used for the sunrise/sunset information, the "Air Quality" screen (in California), where it was used for the
entire background, and if a page didn't load immediately, you could see the background while the blue box was being drawn in front of it. The 4000 was essentially one layer on top of another, ad nauseum, and sometimes the computer had a problem drawing certain layers at certain times. If the top banner didn't load, for example, you'd see the top line as used on the WeatherStar III, as the 4000 used all the same information as the III, but it was able to draw graphics to replace some textual information.
My next question is about the font for "Local Radar" and "Current Radar". Is that a different font from the STAR4000 fonts? None of the ones I have installed match the font for that text. The closest one is the STAR Radar font, but it's all CAPS.
The original radar font was that which you see in the font set. However, as a result of the most recent update to the 4000, which was some time ago already, the font changed to a more streamlined and narrower helvetica-type font. This hasn't been included in any of the font sets that I've seen available.