Still struggling to make a "simple" 5Watt PA for the 1.8 - 50MHz range The QRP-LABS IRF510 5W PA will not deliver more then 1W at 28MHz not to speak of 50 MHz there it is an attenuator. The U3S LPF needs to be terminated with real load to keep the signal a bit decent. Using the RD15HVF1 Mitsubishi did bring just a little more. 3-4 W at 28 and 1.5 W at 50MHz The QRP-LABS PCB has extra pads for the RD15HVF1 that have crossed drain and source. The RD15HVF1 source the middle pin and cooling flange direct screwed a heathsink. The cheap eBay RD15HVF1 are fake IRF510 stamped as RD15HVF1 The real RD15 has low Gate capacity approx 83pF while the IRF510 has 400pF or more and the source and drain are crossed. eBay is poisoned with fake transistor sellers. Like 5 pcs RD15HVF1 5$ good quality ... The specs of the ( REAL) RD15 look perfect, too good to be true! FEATURES High power and High Gain: Pout>15W, Gp>14dB @Vds=12.5V,f=175MHz High Efficiency: 60
Ham radio in JO33hg31 53.15N 6.35E