Currently a new draft european standard prEN 50561-1 is widely discussed. Amongst defined notches for amateur radio bands and dynamic notching for shortwave radio stations it also includes raising the allowed levels of PLT signals on mains lines by about 30dB ! This would mean that any SW radio close to such modems will be impossible.
There is a big discussion in forum.darc.de and in hamradioboard. There is the assumption that raising the levels for PLT will cause other electronic manufacturers to claim for higher interference levels as well. In addition future PLT modems will sure also work up to several hundret MHz to get the high bandwiths required for video streaming. This will affect VHF radios, broadcast radio and even TV broadcasting.
Therefore there is a openpetition which allows you to demonstrate your opinion against PLT devices and against this draft european standard:
https://www.openpetition.de/petition/online/schutz-der-ressource-frequenz-vor-elektromagnetischen-stoerungen-durch-plc
Some very interesting background can be found on the pages of the IRT:
http://www.irt.de/de/publikationen/technische-berichte.html
The german body for elaboration of electronic standards DKE will meet today (Oct. 22th) to decide if they will vote for or against this draft standard on european level. Whatever this decision will be it makes sense to vote against PLT in the petition above…