There are two common problems facing projector owners who want to watch TV on their projectors: Many projectors don't have a coaxial cable input, and the projectors are often mounted in locations it's difficult or inconvenient to run cables to. For people in this position, a wireless HDMI transmitter might be a workable solution. Wireless HDMI technology isn't as well developed as other wireless technologies, and industry standards haven't been set, as of fall 2010, but the products do transmit high-definition video signals over short distances, enough to get a video from your player to the projector.
Connect the wireless HDMI transmitter to your video source, like your Blu-ray player or game console. Use HDMI cables to connect the two devices if possible. Most models have multiple video input types, but no coaxial cable jack. If you're getting TV over coaxial cables, you'll need another machine between the transmitter and the cable.
Connect your coaxial cable to a home theater device--like a Blu-ray or DVD player--that has a coaxial input and a video output the wireless transmitter has inputs for. If your TV box has a video output type accepted by the transmitter, you can skip this step.
Plug the wireless HDMI receiver into an HDMI input on your video projector.
Turn on the projector and set it to the video source to which the receiver is connected.
Turn on the TV box, wireless transmitter and home theater device the coaxial cable is connected through, if you're using one. Set the transmitter and home theater device to the video source the TV signal is connected to. The projector should display the TV signal.