[Elecraft] KPS1500 fan noises

[Clay Autery]

Roy, contrary to what the other guy said, that is a perfectly logical 
supplement to the OE cooling system.  ANYTHING that reduces the pressure 
at the exit venting will improve airflow over the heatsink.
Increase inlet and exit free area and/or increase inlet pressure or 
reduce outlet pressure.....  all will increase flow volume.

Alternatively/additionally, the industrious owner might also consider a 
custom duct in the back that would provide for adding multiple 120mm or 
140mm high-quality fans set to blow air IN.  I prefer Noctua fans these 
days.  They are quiet, come with anti-vibration mounts built in, and 
there are full anti-vibe gaskets available on some models that prevent 
flow short circuits.  They also come in 3-pin or 4-pin models.  3-pin 
models can generally be set to run at full speed or at 1 or 2 slower 
speeds.  The trick solution would be to use 4-wire fans and your own 
feedback loop controller to adjust the speed dynamically..... albeit, 
you need to test and modify any of the ready-built controllers to make 
sure you aren't broadcasting RF birdies with the PWM.

The benefit to putting fans in back blowing through the stock 
screen/fans is that you get the slight added benefit of over-pressuring 
the chassis which tends to keep the chassis interior cleaner. Assuming 
adequate rear spacing, you can hide the fans a bit more....

I could go on...  I love thermal control stuff...  I'd be interested to 
see the numbers on how much power/heat is dissipated at 1500W key down...

73,

______________________
Clay Autery, KY5G
(318) 518-1389

On 05/21/18 14:32, Roy Koeppe wrote:
>
> "Do the KPA1500 fans push air into the box? If so, why doesn't the 
> KPA500 fan do that. If the KPA1500 fans pull out of the box why would 
> it be appropriate to use an additional fan that opposes this airflow?"
>
> Yes, they do...which is also opposite of airflow in K3s. The idea of 
> the additional fans is that they are much more quiet than the built 
> ins, even when they are on speed #1 . And they prevent the built ins 
> from running so much or not at all. Simpleminded, I admit.
>
> Roy   K6XK