DEW attack in Canneto di Caronia?

[Maxmars]

It would be a lot of work, but you could try to turn one room in a kind of Faraday cage to see if it makes any difference. Or you could make one around one of the more affected appliances.

That might be a fascinating project! 

Although measuring or assessing the RF signal 'exclusion' might require some special equipment. 

I recall the old "place you cell phone in a "metallized" mylar potato chip bag... and no cell signals can get through." 
I am uncertain of the practices veracity, but anecdotally it is said to work.

The problem is that signals can be made to travel through the power conduits...