So still leaning here and I can't seem to find much on Reference input, I am not to sure what it is and there for I don't know if I should be using it. I have seen sync Generators and could run out and buy them but I am not sure if this is something I need.
Info on my crazy set up:
I have 4 HVX200's out in a field unmanned about 300ft out (HVX's only have Analog out)
So from the HVX it goes to cat5e transceiver runs approximately 300ft into my control room to another transceiver. from that it is converted by Blackmagic's analog to sdi mini converters then into a Kremer SDI 8x8 matrix and from there into the Blackmagic Hyperdeck studio.
The "reference input" is indeed for syncing your cameras to your switcher (and each other) and is the same thing as genlock. Here's an oversimplified explanation.
What it does is tell each camera, and your switcher, when to send (camera) or expect (switcher) the first line of video to be sent down the cable. Without it, your camera could be sending line number 12 while your switcher is trying to send line number 400, and the switcher has to "wait" until the camera sends the rest of the lines in between in order to send the line that it wants to. The delay, however, is usually only 1, maybe 2 frames, and at 30 frames per second (technically 29.97) is about 33 - 60 miliseconds.
Depending on your situation, however, that may not be a problem. It is usually most apparent in live audience situations where you have the camera showing on a large screen (ie. jumbotron or IMAG). If you did want to use it, you would have to run a separate cable to each individual camera and also to your switcher, and the camera itself has to support it as well (consumer cameras don't).