An article on RT: Russia to stop ferrying US astronauts to ISS from April 2019, is accompanied by a photo of a ground-side radio array consisting of four separate parabolas merged into one pointable element, seemingly tracking the ascending Soyuz.
Why would one subdivide the array like that? There does not seem to be an immediate advantage over a single, larger parabola.
Here are some overlapping possibilities I could think of:
- Economics: It may be cheaper/faster/less finickiy to build four separate smaller parabolas instead a single large one with the same surface.
- Technological/Physical limitation: Maybe emitters and receivers need to be put on different parabolas, so you need at least two parabolas in any case.
- Redundancy: You have four, so no problem if one receivers or emitters go down, scheduled or otherwise.
- Sturdiness: The supporting grid might be sturdier on this construction for the same budget.
- Environmental: Wind or temperature swings give too many problems with a large parabola.