High Definition makes for beautiful images, but localized distribution of those images can be difficult. HDMI runs about 50′ max without needing expensive cables. HD-SDI is better at about 300′, but most large monitors don’t have an HD-SDI input. What every flat panel ever sold does have though is a built-in TV tuner.
Contemporary Research makes products that take a uncompressed HD input, compress it, and then put it onto a high definition TV channel. So all you have to do is run cheap, regular coaxial RF (you know, cable TV) out to the various flat screens throughout your venue, and then tune those TVs to the appropriate channel that you have created. This is great for churches, arenas or convention halls. If they are in an older building, most of those facilities will already have the cable installed in place.
One other nice part of their system is that in addition to the channels themselves, Contemporary Research has devised a system where control signals can be sent down the same wire. This necessitates installing a custom box at each TV, but the huge advantage is that you can change the channel and turn those remote TVs on and off from a central location, rather than running around to a hundred TVs in your facility and addressing them individually. You can even do this from anywhere in the world using their iOS application. Pretty cool, and a cost effective use of old infrastructure.