I used an RTLSDR to look at the spectrum. If you're plugged into the wall, you get ripple. Also the harmonics are pretty loud too. The WSPR example above shows

I used an RTLSDR to look at the spectrum. If you're plugged into the wall, you get ripple. Also the harmonics are pretty loud too. The WSPR example above shows the filtering they put in. In theory at low power like someone else said it isn't ideal, but wouldn't upset too many people so long as you didn't amplify before filtering.