Unfortunately, it's likely from the geoengineering-sprayed chemtrails containing metals that like form much of the clouds these days. Creates layer of metal particles that reflect back the EMF/RF from Earth's surface. We're creating somewhat of a weak Faraday cage here on Earth, it would seem.
As a side-note, that meter is of course primarily designed to prove that the greenwave filters work wonderful.
Same story with the stetzer scam.
Nevertheless this meter is useful to find and remove or replace or properly filter sources of dirty electricty.
Proper filtering should clearly reduce both the differential and the common mode noise at present frequencies.
A real line filter is not plugged in but positioned between the source and the rest of the wiring.
It contains not only one or more capacitors but also one or more inductors.
One might need several filters in conjunction in order to cover the necessary frequency-range.
http://www.lowemfoffice.com/filters_overview.htm http://www.emfrelief.com/capacitive-filters.html http://www.conradbiologic.com/articles/EMFscams.html https://www.youtube.com/watch?v=1Hx1aCMl0l0 The last link is new on this forum, the guy obviously did not want to waste any money on a hyped DE-filter.
The capacitor he employed instead likely did a better job anyway.