[CQ-Contest] Amplifier venting

Kevin Stover kstover at willinet.net
Thu Sep 27 01:12:39 EDT 2001


We've been doing the same kind of thing with over clocked computer CPU's 
for years. When you over clock a CPU you dramatically increase the heat 
produced by the chip. Adding a bigger heatsink and fan to the CPU helps but 
the hot air generated needs to be moved out of the case. In that situation 
we want to establish a negative pressure differential inside the computer 
case to help move the hot air out.
Most computer cases have a fan down low in the front sucking cool air in 
and the PSU fan up high and blowing hot air out. When we over clock we add 
a second fan to the rear of the case up high. There's no chance for hot air 
to stay in the case.

In the case of the amps think of the original blower as the cool air supply 
and your ducting/remote blower as the hot air exhaust.
As long as the outboard blower has a higher cfm rating you are creating a 
negative pressure differential in the ducting and moving the hot air out. 
It might be worth installing a temp sensor or two inside the case for some 
before and after measurements.

Kevin, NØRKX

At 05:22 PM 9/26/01 -0400, you wrote:

>I'm in the process of designing a venting system for both of my=20
>amplifiers, each using a pair of 3CX-800's in a SO2R environment.
>The reason for doing this is twofold.  Calling CQ continuously for 48
>hours tends to increase the temperature of the amplifier itself, and=20
>running additional cooling should help prolong the life of the tubes
>as well as other components.  The second is to regulate the shack
>temperature.  It seems I'm constantly making runs to open and close
>the basement door that leads to the garage in cold weather, and causing
>the AC to run excessively in the warm weather.
>At Dayton this year, I bought three new identical squirrel cage fans. =20
>They move LOTS of air, but are VERY noisy.  My plan is to have an=20
>HVAC company make hoods that would attach directly to the amplifier
>case with double faced tape, right above the exhaust holes for the =
> >From the exhaust I'm planning on using the 4" flexible "tin-foil" type
>ducting run above my drop ceiling, then out to the garage where the fan
>can be mounted.  Hopefully this would dramatically cut down on the=20
>shack noise, having the fan so far away. =20
>Any experiences you've had, or ideas that you have would be greatly
>appreciated so I don't end up re-inventing the wheel! :-)
>Scott Detloff K8DX
>Paris, Ohio
>Visit The North Coast Contesters @  www.qsl.net/ncc
>Tour K8DX @  www.qsl.net/k8dx
>CQ-Contest on WWW: http://lists.contesting.com/_cq-contest/
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