[Hammarlund] Tube shields and heat

[Kenneth G. Gordon]

On 27 Sep 2014 at 13:31, Guido Santacana wrote:

> As for tube shields, if they are not IERC shields, paint will not do much. 

Guido: on the basis of experiment, FLAT black painted tube shields reduces 
the heat in the tube by 17%, so yes, it does do something worthwhile. For 
instance, reducing the heat of 300 degrees to 249 degrees, or -51 degrees. 

You may not think this is worthwhile, but I do.

According to my reading on the subject, reducing tube heat by even 1 degree 
contributes significantly to longer tube life.

> Better to leave the tubes uncovered and use the fan. 

True.

Ken W7EKB