[R-390] Black Tube Shields, IERC

[2002tii]

Tisha wrote:

>A few years ago I went through the process of measuring envelope
>temperatures on a wide range of tubes in a SP-600 with different tube
>shields. It did turn out that the black IERC tube shields did make a
>difference in envelope temperature.

I'm not finding my copy now, but there was a long report documenting 
this published in the '50s by DOD or someone.  It is sporadically 
available on the Internet.

Best regards,

Don