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[TenTec] Heatsinking and fans....was: Pegasus -horizontal operation?

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Subject: [TenTec] Heatsinking and fans....was: Pegasus -horizontal operation?
From: pito@nera.no (Piotr Tomczak)
Date: Wed, 15 Mar 2000 09:56:12 +0100
>The inefficiency of heated air convection?
>
>My recommendation for any and all heatsinks is to have a fan oriented to
>keep air flowing across the heatsinks at all times.  An acquaintance of mine
>lost his Omni VI+ finals while operating Field Day.  He was operating
>outside, under a covered pavilion, in 90 degree temps, and no breeze.
>
>My Omni VI's have fans for each.
>
>Besides, the nice air flow from under and around the radios keeps the
>operator fresh, too.
>
>Get a 12v fan and plug it in to your Pegasus or PS aux V+ jack. Same goes
>for you VI/V/Paragon/Corsair, etc, owners, too!
>

Hmm....
You do not have a fan if you have a good designed heatsink.
But the heatsink in OMNI VI+ is not adeqaute. It is too litlle and
its fins (ribs) are mounted horisontaly. It means you loose again lots of
cooling efficency. (cooling will be degradate but a factor of 60%)

What I did was to change the whole heat sink with a propper one.
I did calculate the theoretical dissipated power and did choose the ambient
temp
to be 30 deg Celcius. The fins are vertical which make the air cool the heat
sink in a natural and proper way. 

Thanks to that design I can operate my OMNI VI+ for hours (CW) in 20 deg C
ambient and the heatsink is mearly warm (35-40deg). 
No need for fan !!!! (even if I have one in my drower for just in case...)

The jobb took only two days of porting and 25$ for hardware.... 
I hate fan noise...

Piotr LA9HFA


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     ·    · 
       o      
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Piotr Tomczak           Ham call: la9hfa
Nera ASA                   E-mail:    pito@satcom.nera.no

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