Discussion in 'Amateur Radio Amplifiers' started by AA7QQ, Jul 3, 2017.
That will work great.
So there are no copper heat spreaders for the transistors to thermally interface to....
Of course, it will.... Many think my ideas may be strange, but I like to find unwanted or cheap things & repurpose them. To me, I throw some money at it & some time. No big deal.
Nope, none at all. Here's the deal. I have a 4-BLF278 MRI pallet that uses less heat sink than what I am going to use in this project & I will add the water cooling. It'll be just fine. If not, I'll press another layer of tubing in for more flow. Or, I can always back it up with fans.
Both of my other amps (4-BLF278 & 6-BLF-278) do not use copper spreaders at all. These are not 1.2KW LDMOSs.
I don't think that is strange, I thought about doing it also, I also saw the potential problems with making that work.
But what you have should work fine.
It will be interesting to see how much heat can be removed from the heatsink.
I had wondered about that...
I have a motorola MSF-5000 paging transmitter PA module, three of these were used for 350W on ether UHF or 900MHZ.
I don't remember. They have a 2"x2" by .250" copper heat spreader under the transistor.
I already have thermocouples from another project that will be under one of the hold down screws. They will all be monitored & probably kick the fans on if ever needed. I am pretty confident it will work just fine.
Instead of 180's make a header on each side, better flow and better heat transfer
Well, since I switched to copper tubing, from aluminum, that is the plan. I will solder up a simple manifold & check for equal water flow. If there is any issue, I will restrict needed lines to even them out.
You should not post about things you know nothing about.
It's kitchen table simple to lap a aluminium plate to a mirror finish.