Investigating QRM from Powerline Ethernet Devices with a Funcube Dongle

Over on his blog Andrew has posted a good writeup where he determines the QRM (interference) effects of a PLT (power line transmission) device. PLTs are also known as ethernet/internet over powerline devices and they are devices that plug into an electricity socket and use household electricity wires to create a computer network, thus eliminating the need for ethernet cables or WiFi. However, many hams and radio hobbyists hate these devices because they believe that they can cause significant amount of radio interference, especially on HF.

In his investigation Andrew bought a pair of Netgear Powerline 500 PLTs. He then plugged the PLTs in and started streaming a movie over the powerline network connection to cause maximum radiation. Then using his Funcube dongle and SDR# he investigated ham bands to see if these devices brought any noise.

In his results Andrew writes that he barely saw any interference caused by these devices. Some interference was noticed at 17 meters and 12 meters, but he notes that the amateur portion was left relatively unaffected. Many hams believe these devices can completely wipe out HF, but it seems that this is untrue, at least for this particular PLT model.

Netgear PLT devices
Netgear PLT devices

3 comments

  1. john Gulliver

    I have plt interference affecting HF VHF low level 50hz humming across HF bands and VHF with a white noise that is somehow imposed onto the signals i receive.Ofcom is not interested and has closed my case claiming that interfering signal is not harmful? effectively rendering hf useless.Ofcom is not fit for purpose and should be held accountable for their no regulating of the spectrum.Amature radio will soon be impossible to operate in urban areas with the increased noise floor due to non-compliant devices allowed to pollute the HF spectrum why isn’t the RSGB going something about it? Get a petition going no confidence in the regulator Ofcom I’m sure they would be able to announce it on the Sunday news broadcasts.Or is there something going on that we don’t know about certainly makes me think so.

  2. DJ0MY

    Even the new ones are extremely bad for all shortwave listeners. The ham bands are notched out in the newer models, but the rest of the HF band is still as badly polluted as with the very early models. HF (= high bandwith data) does not belong to and shall not be modulated onto house wiring.

  3. Andy

    Early ones were bad, the notching on later models is much better, my neighbour had the early ones, complete S9 1MHz to 25MHz, Ofcom made BT fit Ethernet cables, done within 2 weeks..

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