Jeff Liebermann wrote:

On Thu, 17 Jan 2013 19:18:48 -0500, "Michael A. Terrell"
wrote:

IR is heat.

Nope. Long wave or far IR is heat. Short wave or near IR is ummmm...
near IR. Note that there are various division of IR:
http://en.wikipedia.org/wiki/Infrared#Commonly_used_sub-division_scheme

High temperatures mask IR signaling.

Nope. I can prove it with a simple test. Heat up a frying pan and
put it in front of IR receiver window in your TV, hi-fi, or whatever.
That should belch many watts of heat in the IR region. Then try using
the IR remote control. It will work because the 8000-15000 nanometer
wavelength of the IR "heat" from the frying pan is quite different
from the 850 nanometer wavelength of the IR emitter in your remote
control.


Try that outdoors, in the bright sunlight where it isn't a narrow
slice of IR.