Duo and WSJT audio


david
 

Hello All,

I'm looking for guidance (or reassurance) with the setting up of my Duo for
WSJT-X. Let's say for FT8.

I have followed the Elad Application note, and have picked up snippets from
old messages here, although I didn't pay much attention in the past as I
have only recently obtained the Duo.
The set-up is fine - no hitches with most of the settings. But I am most
concerned to put out a clean signal, and that is where I need your help. I
can transmit into a dummy load and 'sniff' the signal using a Perseus SDR.
When I use the 'tune' button in WSJT (which produces a 1kHz tone), I see my
fundamental signal exactly where I would expect it. But there are harmonics
1kHz either side of it.
These harmonics are about 50dB below the fundamental. No changes I make to
the audio drive level in WSJT make a difference to the relative levels. If I
go down low enough in drive level to remove the harmonics, the fundamental
disappears, too. I've tried 'fake-it', 'none', and 'rig' without removing
the harmonics. Is there something else I should try? Or is 50dB down
something I simply shouldn't worry about?

Best Wishes
David, GM8XBZ

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