Convert HDMI video to Coaxial Antenna? I need to take an HDMI (unencrypted source) from a Sony video camera and send it via coaxial cables which are hooked directly to TVs wired throughout the building. I'd like to be able to tune into i.e. Channel 3 to tune into the video signal. 

I've searched and the only solution I can find is an SDI to HDMI converter, but I'd rather not use that and would prefer to hook coax directly to the TV as below:

Camera (HDMI) --&gt; [CONVERTER BOX??] ==coaxial==&gt; TV
                                     |=========&gt; TV
                                     `=========&gt; TV  (etc)
Assuming you want digital channel 3, you can use an HDMI to QAM modulator, like this one or this one. You will need appropriate multiplexers, amplifiers, and splitters to combine your feed with your CATV provider and then distribute to the TVs.

If you need analog channel 3, then it is more complicated. You will probably first need to convert to SDI, then convert to analog video and audio, and finally feed an analog modulator.