I have a Mac Pro (Mid 2012) Processor 2x3.06 GHz 6-Core Intel Memory. 64 GB. DDr3 Graphics. ATI Radeon HD 5770 1024 MB We use this system at the church and run an overhead projector and three TV monitors from it. The overhead picture is perfect and operates flawless. However the three TV's are another story. Two of the TV's are in the foyer about 15 feet from the computer and the other is on the back wall of the sanctuary about 15 ft from the computer. Some days the two in the foyer are clear as a bell and on other days they are so jumpy and blurry we have to turn them off. The one on the back wall will seldom work. When it does it is in black and white and never color. It usually says on a few minutes and then begins floating a warning that there is no signal. How can I boost the signal to these three TV monitors? They are all three being connected with coax TV cable. I now of churches that run multiple TV monitors throughout the building and don't seem to have a problem. What am I doing wrong? Or what do I need to do to make the connections more usable? Thanks for your help!!