RTL-SDR has released a video showing the HF interference problem from Ethernet over Powerline Devices

Ethernet over Power, Powerline Networking, Powerline Communications or ‘HomePlug’ is a technology that allows you to use any of your household power outlets as an internet Ethernet port, completely eliminating the need for runs of Ethernet cabling. They are capable of high speeds and can be used anywhere in the house assuming the two plugs are on the same power circuit.

Unfortunately, these devices tend to wipe out almost the entire HF spectrum for anyone listening nearby. As household powerline cables are not shielded for RF emissions they radiate in the HF spectrum quite heavily

Full Story - http://www.rtl-sdr.com/showing-the-hf-interference-problem-from-ethernet-over-powerline-devices/