output V over 50Ohm ~72W Rf at input 76W (25Vx 3A) N=96% ! ? V drain puls had to modify the total capacity of C2+C3 to 10+6.8+6.8 nF and the output C4 6n8 + 6n8 to archive maximum output. But at 25V still could not produce 100W out I did change R4 to 1k because of latching problems I had earlier that cost me a few IRF's Drive level increase does not change the output in this class D type switching mode. The Flex1500 XVTR/C port 0dBm at level 30% is sufficient. Also the K3 XVTR out level was perfect to drive the QTX. Class D is perfect for CW WSPR modes. The Drain pulse form seems correct. Optimising L3 for maximum output did not bring more output. Po drops as soon as a ferrite bar is approaching L3. I would expect that L3 could be increased when dropping the frequency from 500 to 475 kHz After re-arranging C2 C3 C4 The output increased to 75...
Ham radio in JO33hg31 53.15N 6.35E