You can convert HDMI signals to coaxial using a HDMI-Over-Coaxial converter. HDMI Over Coaxial converters enable you to send high definition audio and video signals over the existing coaxial wiring in your home. Once the converter is set-up, you can use it to watch HDMI devices, such as a Blu-ray player, or receiver from any room in your home or office.
Insert one end of the HDMI cable into one of the "HDMI OUT" ports on your HDMI-enabled DVD player or other device.
Plug the other end of the cable into the "HDMI" port on the HDMI-Over-Coaxial converter.
Connect the coaxial cable to the "Coaxial" port on the side of the converter. Plug the power adaptor into the port on converter and plug it into a wall outlet to begin converting the signal.