Finally finished a power amplifier for Ultimate3S. The idea I had found on net, see page VK3PE . I contacted Glen and he gave me needed GERBER files to order PCB. Used  Seeedstudio.com and got 5 pcs very quickly. Had some problems to complete components, see my story about fake RD166HHF1 devices. Finally ampilfier is ready and working. I used a piece of aluminium about 20mm thick that I had, drilled and tapped to take the RD16HHF1 and PCB itself. It barely gets warm in 6 minutes ON, two minutes OFF of WSPR mode. Bias settings 600mA as recommended by Glen.With typical 100mW drive from single BS170 in WSPR board, get about 2-2.5 watts output from the amp.