Hi Folks, I was more modern, I had a tone comparitor hooked to my Kenwood TS 520. It worked fine. I was at a friend's house and he had a National NCX3. I don't know how he tuned it, but he used the power supply hum for a side tone. How many remember doing that? 73 88 Walt and GEB dog Opus WA4QXT New London CT mailto: [log in to unmask]