[Drake] Cooling fans - blow in or out?

[ed brooks]

Exactly what I do.  I put cotton swabs (like Q-tips) through the four 
holes of the muffin fan.  They serve as cotton feet, keeping the fan 
from actually touching the radio, which reduces noise and vibration.  
The fan is placed partway over the T4XB final compartment and partway 
over the Receiver, which is just an inch away from the transmitter.  
Keeps them both cool to the touch.  Was concerned it might not allow 
them to warm up enough to be stable but that has not been a problem. 
Been operating with the fan for two years.  After a ten minute warmup 
they will remain on freq (I monitor the maritime net) for hours on end 
without any retouching at all.  Even with the 'feet' the fan is somewhat 
noisy, as it is a four inch AC fan, but since I do not use any amplified 
microphones or speech compressors, it is not a problem at the other 
end.  And it circulates rig heat to keep the shack warm.   The fan is 
plugged into the same power strip that controls the transmitter and 
receiver, so it comes on with the rig and goes off with the rig.  Yes, 
it 'sucks' air upward from the radios. 

Ed, W5HTW



Jamesnf at aol.com wrote:

>Chris:
>
>I cool my T4X-C by placing a small muffin fan on the top of the cabinet over 
>the tubes pulling air out.  I glued some soft gasket material to the edges of 
>the fan and simply sit it on the cabinet, not attached by hardware.  
>
>My thoughts on doing it this way....... Drake designed the transmitter to 
>cool via convection.  Warm air rises and passes through the roles in the top of 
>the cabinet and is replaced by cooler air entering through the side and bottom 
>holes.  I just wanted to enhance this process, so I gently (and quietly) pull 
>air out.  Another advantage is that the warm air leaves upward and out from 
>one spot.  If you blew air into the cabinet, warm air might leave from the 
>sides, the bottom, the edges of the top, etc.  It might even blow onto the 
>neighboring R4-C through the side holes.......don't want to do that!   
>
>The cabinet is noticeably cooler with the fan than without it. It was a 
>quick, cheap and simple project that seems to work.  My favorite kind!
>
>Jim W9TN
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>  
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