Check the specs for the temperature/humidity parameters. I haven't found many that state they'll work above 104 degrees F or 95% humidity (non-condensing).
If you can get an outdoor-rated TV with a built-in HDBT receiver, that will be your best bet as the receiver will get proper thermal management from the display. If you stick another receiver in the water-tight compartment, it may be baking itself to death.
Other than that, we've seen a lot of cheaply made power supply issues with certain manufacturers.
Edit: otherwise, mount the RX side in a climate-controlled environment and use an HDMI cable of appropriate length through the wall OR just use a fiber HDMI cable.
