uBITX -Regarding the PA transistor heatsinks.

Peter LB0K


I can see the insulation argument to why these are installed hanging on to the IRF510s but this puts a large mechanical load on the transistor legs and increases the risks of damage especially if one tried to use the uBITX as a portable, even as a SOTA rig.


One could fit a larger heatsink that was fixed to the chassis/casing or PCB and one would then have to add rectangular insulating washers between the transistors and the heatsink.
These changes would increase the parallel drain(s) capacitance to ground


What sort of negative results should/could one expect from these measures?

 And could one fix'em?


I envisage these positive results:-

-       better mechanical strength

-       easier to provide controlled cooling of the heatsink.

-       a slight increase of weight

Someone has suggested use of  very beefy
6400BG heatsink, this has two solderable pins installed in the one end of the profile. However the uBITX board has no room for these.

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