modifying heatsinks - anyone tried this?

[archjeb]

Hello all,

I know several threads have discussed issues with using mobile radios (such as the Maxtrac/Radius) for repeater usage because of their designed duty cycle.

Besides adding forced air cooling with fans, has anyone tired extending the cooling fins with aluminum using a thermal adhesive such as Artic Silver adhesive? It would seem that it would help with having more thermal mass and surface area.

On a side question, at least on the Maxtrac, is that the only issue with longer duty cycles is the PA and heat? In other words, there are no other components that would be the limiting factor? (ya I'm aware of the RX/TX algorithm the microprocess uses to lower TX power, I wondering more about heat generating components)


I was going to try and add maybe four inches to the fins and use an infared temp sensor to measure before and after.or maybe just use the hand touch method

-J

 

[Captain Kilowatt]

Not sure how effective it would be to simply extend the fins as you need thermal mass to pull the heat away from the device and the fins to simply dissipate it. Extending the fins may simply result in the bulk of the heat dissapating before it reaches the end of the fins. A larger piece of aluminum bolted directly to where the existing heatsink is bolted would be better. Amplifiers designed for repeater use are designed this way with simply a larger heatsink.

 

[KD2GOE]

I work with a lot of computers and over clocking of the cpu and video card.
Your best bet would be to add to add a large amount of aluminum gives the fins and fans the time to wick the heat away So it takes longer to heat the block then it takes to cool it.
What i would do is remove the old heat sink mill the fins off and make a new mounting service for a large aluminum heat sink or fined a way to replace it altogether .
1 other way is to water cool it. Mill the old heat sink flat and add a water block. With a supporting water pump and radiator.

 

[Moleculo]

On a side question, at least on the Maxtrac, is that the only issue with longer duty cycles is the PA and heat?

Yeah, that's pretty much the only issue.