Quote Originally Posted by enauman View Post
I have a feeling that the welders EMI is pretty broad spectrum.
I suspect you're right. I did a search but did not find a definitive answer - some said it only affected AM, some said it also affected FM, some said it even affected TV. All of the manufacturers seemed to have instructions on proper grounding, etc. to minimize RFI but none said what frequencies were involved.

I used to run a company that sold precision machinery to the sheetmetal industry so I visited a lot of aerospace manufacturing plants but I retired at about the time that all but a few leading edge companies were just starting to wire their facilities for automated data collection so problems like this were still to come.

We had electronic controls on most machines but they were self-contained and did not communicate. I cannot recall an instance where EMI/RFI caused us problems.