I decided to buy the amplifier module as a kit from James Klitzing, W6PQL, where all components were included. The copper heat spreader, however, was purchased from PE1RKI Bert. I opted for the version prepared for watercooling.
The core of the SSPA is the 1 kW amplifier module. The module is built around the LDMOS transistor MRFE6VP61K25H from Freescale. This device can operate between 1.8 MHz and 600 MHz and delivers 1250 W output. In this application, the output is limited to 1000 W.
The photo below shows how small the 1 kW module is. Dimensions are 12 cm x 8 cm. But the copper heat spreader is 2 cm thick and weights 1.5 kg. This size is necessary, because the heat spreader must be able to transfer up to 400 W.
1 kW amplifier module for 2 meters.
A low-pass filter follows the amplifier module in order to suppress harmonics of 144 MHz. The physical size of the PCB is the same as the amplifier module. A directional coupler is included, which allows monitoring of forward and reverse power.
1 kW low-pass filter for 2 meters.
This project is still in progress and the 'smoke test' should be completed soon.
Lars Petersen, OZ1BXM