[TenTec] Jupiter - duty cycle for digital modes

[Dr. Gerald N. Johnson]

On Sat, 2007-06-02 at 15:00 -0400, ron wrote:
> waltk8cv4612amos at att.net wrote:
> > Oh, and the other option I use is a 3" computer fan ( 100 volt one ) just 
> > wired to a power plug and sitting behind the radio blowing air at the heat 
> > sink. Lot cheaper :-)
> >   
>  
> Gang
> 
> I know this is subjective but,
> 
> isn't it better to have fan blow AWAY from heat sink?
> 
> Ron, wb1hga
> "got PSK?"

Depends on the shrouding of the heat sink and the fan and the location
of the air filter or where you want the grunge to accumulate.

I think the heat sink will run cooler (despite the slight added heat
from the fan motor) with the fan blowing air directed at the heat sink.
That air will be more directed and higher velocity (which is what it
takes for good heat transfer) and will impact more of the fins than air
being inhaled without a good control shroud over most of the fins.
-- 
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer