[R-390] Tube cooling

[rbethman]

Painting a chrome plated or other plated shield won't help a single bit.

The IERC shields are "more" than simply anodized black.

They have an internal sleeve that contacts the glass. Additionally, they 
have bases that are mated to the chassis.  The entire design is all 
about taking the thermal energy, heat, and to dissipate it to the 
surrounding air and through the chassis.

There is "some" debate as to whether to simply leave the tubes without 
shields *if* IERC ones aren't available.  The simple reasoning would be 
that it may be better to let the tubes radiate the heat directly into 
the air in lieu of trapping it inside a shield that basically was simply 
meant for the purpose of keeping the tube from coming out of its socket 
during transport or in a mobile installation.

Heat is the biggest killer of tubes other than a component failure 
taking the tube out.

If the radio is rack mounted, you are probably better off using some 
cooling means such as a muffin fan or two.

Bob - N0DGN


On 4/18/2013 1:45 PM, Gordon Hayward wrote:
> I wonder about the idea of painting shields to make them black.
> Wouldn't the thickess of the paint polymer act as an insulator?
> The black IERC shields look like they've been anodized black
> which is a lot thinner.
>
> Cheers, Gord VE3EOS
>