I always wanted to try making making a cw transmitter like the one in KD1JV's PFR-3. It looks so simple. Steve uses the square wave comparator output of the AD9834 into an *74HC02 quad nand gate to buffer the output into 3 paralled BS170's. Since the Si5351 already puts out a square wave - why not? A quick test gave me 4 watts into a dummy load. I added a 40M LPF because I plan to lash this up with an already built CRX1 since it has some nice built-in conveniences, like TX/RX switching, muting and a nice twin-T sidetone oscillator. Spectral plot of output.