432MHz 1000W PA

I have used my old 400W PA for 432MHz for several years, but since it never was built into an enclosure, it was obvious to make a brand new 1000W PA instead. I had a surplus Plish 2000W water-cooled PA ready to rebuild for 432MHz. It’s quite large, and imposible to find enough room for on the shelfs in my little shack. So I decide to make a more compact version. -and 2000W is also more than needed.
Summer of 2021, I found what I was looking for, – a 1000W 432MHz PA based on LDMOS for 50V. Included in the deal were splitter/combiner and a 3000W 50V SMPSU. February 2022 I was ready to test the performance of the PA.
After some adjustments, I ended up with the result which can be seen in the video below.

1050W output @12W input. 50V 40A drawn from PSU.

I acheived almost the same data as F5FLN, so I’m satisfied with it, and continue the project. 

During the fall 2021 I found an nice heatsink I believe will fit perfect for 2x300W dispatched from the pallets, but fans will be needed for sure.
– noticed during the test that RG400 is to losy for 432MHz 1kW, and get’s extreemly hot, so I’ll replace it with some 1/4″ semirigd that was left from my 1296MHz PA project.
Enclosure has also been found. For this project I decide not to use a surplus solution, as the surplus enclosures I had, was either too big, or too small.
I found a 19 “rack-mounted enclosure at RS that just fits perfect  into this project.
Link to the enclosure by clicking on this line

At the shelf I had other good parts for this project:

  • High power directional coupler (same as used at my 1296MHz PA)
  • High power coax realy “RCT RDL-SR012” rated for 800W at 432MHz
  • W6PQL sequenzer “The Ultimate Amplifier Control Board” version 6.3

Asembly is ongoing, story to be continued…

Below is the original documentation from F5FLN