Hello, I am building this signal generator http://qrp.gr/rfgenerator/ and I notice that the harmonics are somehow increased in the higher bands (10-30MHz or so) from -40dBc to about -30dBc. I wonder what is the reason for that and what can I do to correct the problem? I have tried a fixed 30MHz LPF at the output which reduced the harmonics at 15MHz and above indeed but also affected the output frequency range of the generator, so I removed it. I may bring it back at the future but after a preceding attenuator, so as to hopefully isolate it from the buffer. I have also noticed that the switched attenuator I have used at the output, affects the output frequency a bit differently, dependent on the switching attenuation value (more attenuation, more pulling). Any guess what to do with this? Maybe adding a fixed attenuator prior to the switched one?