[hpsdr] Munin heat sink and spreader

[Berndt Josef Wulf]

G'day,

can confirm this. It also has about 0.5mm gap in the centre. Not sure if
it is the copper spreader, heatsink or both. My have it milled flat to
provide maximum heat transfer.

73, Berndt
VK5ABN

On Wed, 2013-10-09 at 22:36 -0400, AA8K73 GMail wrote:
> ***** High Performance Software Defined Radio Discussion List *****
> 
> 
> Has anyone else noticed a concave surface in the heat sink in 
> the latest Munin kit?
> 
> When I hold the copper spreader against the heat sink, it 
> touches on the ends, but the middle portion is about 1 mm away. 
>   I could:
> 
> 
> 1. File the copper spreader and/or aluminum heat sink to get a 
> closer fit.
> 
> 2. Put the copper spreader in my arbor press and bend it to 
> conform to the heat sink.  But then it wouldn't be flat for the 
> transistors.
> 
> 3. Fill the gap with something to provide a better heat transfer 
> than air.
> 
> 4. Not worry and just screw it together.
> 
> 
> What do you think?
> 
> 
> Also, what about using Penetrox (zinc particles in petroleum) in 
> place of ordinary heat sink compound (ceramic particles in 
> silicon, I think) for the spreader/sink interface?  I've used 
> Penetrox frequently in industrial electrical work when joining 
> aluminum with copper.
> 
> 
> Mike - AA8K
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