- I removed out the both transistors and the circulator.
- PCB, both transistors and circulator was puted in the heatsink (simple flat heatsink).
- All fixed with screws. The most difficult job is to mark drill holes and cut threads.
- Transistors and circulator soldered into their places on he PCB by slightly bending their leads (they have sufficient margin). This is simple.
- PCB modifyed as described in the manual of SP8XXN and SP5XMU.
- Unfortunately, PA hav`t PTT. Therefore, a relay was added from the outside of the PA. This PTT relay is switched on +26 V during TX.
Are you using the original circulator? Unsolder and solder is a great idea to eliminate the gap between the pcb and the transistors.