Hi,
Basically there are two devices for each channel. The upper device is the source; the lower is the channel modulator. The rack on the left mostly has FTA satellite receivers as the source; they are connected to two dishes. There is one modulator connected to an outdoor camera that lets me see and hear the occasional wildlife in the wooded area behind the house. There is also a Roku for internet sources; and streaming. I use Titan TV to make a custom line up of OTA channels; that source is a Raspberry Pi that refreshes every minute. The rack on the right is mostly OTA sources, 10 local channels; one is just weather (Alabama can have strong storms from time to time). The lowest source device on that rack is a DVD player; I usually loop something just to avoid having an empty channel. There is another small rack (not shown) that has two other Raspberry Pis; those have digitized content - mostly movies and music 6 TB of videos/concerts. That rack also has a Chrome cast for any streaming content that anyone wants to cast on a TV instead of a phone/computer/ iPad.