http://www.hdtvsupply.com/hdmi-to-coax.html
What this WolfPack HDMI to Coax Converter Can & Cannot Do:
CAN DO:
Convert an HDMI signal (like from a DVD player) to a coax signal AND CONVERT THE COAX SIGNAL BACK TO HDMI. The coax cable cannot have splitters.
It will do nothing else.
Think of it as a long HDMI cable with HDMI connectors on both ends.
Both the Transmitter and Receiver MUST be used.
WHAT IT CANNOT DO:
Convert an HDMI signal to a coax signal to go into the coax input of a TV.
Convert a coax signal from the cable company to an HDMI signal.
Convert a coax signal from an antenna to an HDMI signal.
Send a signal through a coax cables that has splitters.
FROM:
http://www.hdtvsupply.com/hdmi-to-coax.html
NOTE 1: This HDMI to coax set includes a SEND unit and a RECEIVE unit and 2-AC adapters and all must be used. It cannot work with only one box and needs both boxes. Think of it as a long HDMI cable going to a TV with an HDMI input. Existing passive splitters drop the signal strength in half, or more, so delete all of the splitters and wire directly. It does not work any other way. Our HDMI to Coax Adapter does not convert a coax cable coming out of the wall from a cable box company. Also the connectors are female BNC so if you are using a cable with a male coax connector you will need the optional BNC to F adapters shown in the options.
NOTE 2: In-house and existing passive splitters drop the signal strength in half, or more, so delete all of the splitters and wire this device directly as it won't work with coax splitters. They should NOT be used in conjunction with connector adapters, signal processors, switches or amplifiers between the Source and Display device. This HDMI Coax Adapter sends only one HDMI signal to a TV with the receive unit at the TV. It does not work any other way. If you are trying to send one coax signal to a TV with an HDMI input, it won't work. One set includes a transmitter and a receiver set. Also the connectors are female BNC so if you are using a cable with a male coax connector you will need the optional BNC to F adapters shown in the options.