QRP Labs HF PA kit Series Manual page 3

The easiest place to take RF from the Ultimate3S is at the Q2 or Q3 transistors. The best way to cut
the RF circuit between the original Ultimate3S PA and the Low Pass Filter on the U3S PCB, is to
remove capacitor C5. If you don't mind a little aggression you can even just cut it out with wire
cutters. For routing the RF output of the 5W HF PA kit back to the U3S, it is easiest to connect a wire
to the "RFI" (RF in) pad.
Single-band Ultimate3S with 5W HF PA kit
3
Rev 1.01