[Drake] Cooling fans - blow in or out? - summary of responses

[Chris Codella, W2PA]

Thanks for the great response folks.  I understand the Drake 4-line, and 
many other rigs from that era, were designed for convection cooling.  
But I don't believe the designers anticipated 35 years of service or 
more, and we now realize that a bit of extra cooling helps things live 
longer.

It looks like the consensus here, although not unanimous, is to blow 
out, as I expected.  My fan is in place now on the back of the T-4XB 
final cage, blowing out and working fine; fairly quiet too.  This 
particular fan has finger guards on the outside when blowing out, so 
even that works as designed.  I used mostly the technique described here 
(http://www.wb4hfn.com/DrakeArticles/TechTips/TransmitterFan.htm), but 
there are several other variants.  As someone here also pointed out, 
sitting to the right of the R-4B, it has the additional effect of 
drawing heat out of the receiver.  The top of both units is now much 
cooler. 

I recommend this kind of modification; it's very minimal.

73,
Chris, W2PA