The blimp, a Tethered Aerostat Radar System (TARS) is inside R2916, balloon and cable to 14,000ft. It’s affectionately called “Fat Albert” and there are two of them. On the charts it is labeled as R2916. Avoiding that restricted area is important for all pilots flying to the keys as well as for controllers. We referred to it simply as “the balloon”.
I was a controller at ZMA and that was my airspace. That balloon broke away from it’s moorings back in 1989 or 90. It floated up V157 toward Miami. The Air Force scrambled and wanted to shoot it. Cooler heads prevailed, and it settled into the mangroves. Supposedly on another earlier break-away, a boat tried to tie up to it and was lifted. If I can find anything on this story I will post it. But this was back in the days before the internet was big.
Here is a link https://bigpinekey.com/blimp-fat-albert-history/