[hpsdr] Munin heat sink and spreader

[AA8K73 GMail]

Thanks gentlemen.

I was thinking of the metal particles providing the thermal 
conductivity (Wiedemann–Franz law), but I suspect that the per 
cent of contact area is small.

When I held the spreader and sink together to check for fit, I 
noticed the gap and turned the spreader over to see if it was 
bowed.  I used a metal straight edge against the spreader and 
the spreader was flat.  Looking at the reflections in the 
spreader, I couldn't find any optical distortion.  I am 
impressed with the quality of that spreader.

Longitudinally, the heat sink is very straight.  It just curves 
transversely.  Thanks for the confirmation Berndt.

I used to maintain copper resistance-welding fixtures 
(ignitrons; too long a duration and they would open the 400 amp 
line fuses), and used lathe, mill, surface grinder, and shaper.

I'm concerned about someone else removing too much material in 
search of flatness.  Too deep and it would require a shim to 
match the transistor to board height requirement; and make two 
more thermal interfaces.  Buying another drilled and tapped heat 
sink would be costly.

I hope to carefully file the sink and take < 1 mm away.


73,
Mike - AA8K


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