[hpsdr] Pandora Fan

[Jeremy McDermond]

On Nov 19, 2009, at 2:44 PM, John Ackermann N8UR wrote:

> Jeremy McDermond wrote:
>
>> The one comment/question I had during the process is why a 90mm fan  
>> was chosen for Pandora.  Since the common PC fan sizes are 80mm and  
>> 120mm, it would seem as if it would have been nice to have either  
>> one of those sizes in there.  It would make getting some of the  
>> fans easier.  As it was, I drilled out some holes for an 80mm fan  
>> instead and it doesn't look bad at all.  I used an Enermax  
>> temperature controlled fan, and put the temp probe between the LPU  
>> heatsinks.  It's really quiet, and I'm happy with it so far.  We'll  
>> see how it performs when I get a Penny/Pennywhistle in there to  
>> really pull some current through the LPU.  If there's ever a  
>> Pandora II, one might want to look into putting spaces for a couple  
>> of 80mm fans in there instead of a single 90mm.
>
> Simple answer... it was a suboptimal decision on the designer's (my)  
> part!

I hope you don't see the comment as an indictment or anything.  In  
general, I really like Pandora and think it's a very good solution to  
the problem.

> When we spec'd the fan, we wanted to use the largest size that  
> reasonably fit in the space available, and 92mm (note, not 90mm),  
> with holes spaced 3.25 inches, seemed like a good match.  We didn't  
> think that the 80mm PC fans would be more available, and isn't  
> *that* much smaller.

It's hard to foresee everything.  Especially in a 1.0 design.

> I'm using Digi-Key part number P11043-ND which when last I looked  
> was reasonably priced at $8.75.  One downside with that particular  
> part number is that it doesn't come with the 3-pin connector on the  
> leads; I haven't had a chance to check whether there's another model  
> that has the connector pre-installed.

I was mainly looking at PC fans because I wanted to grab one that had  
the temperature control on it.  It just made sense to me to have a fan  
in there that wouldn't run full speed all the time even when I'm only  
receiving and such.  There are tons of 80mm and 120mm fans on the  
market that have all that built in.  I bought mine for like $15, and  
it had the cool blinky lights.  :)

>
> John
>
--
Jeremy McDermond (NH6Z)
Xenotropic Systems
mcdermj at xenotropic.com




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