OZ1LPR - Peter, OZ7Z - Allan and I, are working on a 500 Watt PA for 144 Mhz.
Peter has already assembled his PA and we are at the moment testing it wery succesfully when we are on fieldday and exspeditions for OZ1ALS.
There are no problems with heat or function, even after a full test on 6 hours with continius output of 5-600 Watts output.

When I are finished with my PA, there will come more pictures of the projekt, and also a PIC Controller for control of voltage/SWR and heat.
On the display, output can be seen, together with function parameters.

I have worked on my new PA between Christmas and new Year. I have made Many things and made some mayor changes.
Look here: Making of my 1000 Watt Power Amplifier

Meenwhile you can get layouts for PCB to the projekt here:

144 Mhz Input PCB (160x95mm)	144 Mhz Output PCB (160x95mm)	144 Mhz Combiner PCB (160x100mm)

Picture of OZ1LPR PA working full power output

PA from abow, where you can see input power splitter - PA in and out PCB - Output power splitter and Lowpass filter

Picture of input splitter connction to input PA PCB

Between tho PA Input and output PCB is the one of the FET's

Here is the Output PA PCB with the output coil

Lowpass filter in the output for decrease of harmonics