[R-390] Tube Shield Painting

[Nick England]

And painting the outside of the shield flat black actually helps too.
Black surfaces both absorb IR better from heat sources (tube) and emit
IR better to heat sinks (surrounding chassis/components).
It's like low SWR....
Cheers,
Nick K4NYW

On Fri, Apr 19, 2013 at 1:10 PM,  <chuck.rippel at cox.net> wrote:
> Painting the INSIDE of the nickel shields flat black helps.  Its an old
> trick used in RF amplifiers which employ glass tubes.  The idea is to paint
> the
> surfaces around the tubes flat black so that infra-red heat from the tubes
> is absorbed and not reflected by what may be shiney metal surfaces back into
> the dark structure
> of the tube itself.
>
> Its not an IERC or WPM shield which actually wicks heat off the tube bulb
> itself but better than nothing.
>