Yes we have tried other weed eaters and don't see the issue. Have checked grounding over and over again. In the owners manual it does say not to be operated by people with pace makers as the electomagnetic frequency pulses that this unit creates could be fatal. So we know it is emitting something. Looked at it on the spectrum and we can the the interference when the weed eater is running.
This is CABL.com posting #355613. Tiny Link: cabl.co/mbEFR