> In a former job, we built black body radiators used for calibration of
> missile seekers. We used Krylon ultra flat black paint. It had very high
> emissivity at long infrared wavelengths. The aluminum was anodized first
> so
> that the paint would stick.
I'm still amazed why transmitter manufacturers continue to use bare
aluminum material for heat sinks. It is TERRIBLE at radiating heat.
Forced air is necessary for any degree of efficient cooling. To
illustrate this point try the following experiment...
Heat an empty teflon frypan on your stove... (use one that has an
aluminum colored bottom) to something above boiling point, very hot to
the touch but, of course, not hot enough to start burning the teflon.
Remove it from the fire. Then raise the pan with one side facing your
cheek... take note of the radiant heat you feel from the bottom side
vs. the dark teflon side. Dramatic to say the least. Almost none is
felt from the bottom, the dark side radiates a great deal of heat.
Yet, many radio heat sinks are bare aluminum.. go figure.
Dennis
NØSP
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