An example of powerline ethernet interference

Popoutman

Using a sloping longwire antenna from the house eaves to the end of the garden with my KiwiSDR, I noticed some odd signals. After a bit of research and investigation it would appear that one of my neighbours has a powerline ethernet setup of some type. Thankfully they appear to be not using it in any great capacity. I wonder how long that will last..

I thought I'd document the relative power levels here so that people could have a reference and how to recognise this type of interference.

The "capture_no_active_powerline_ethernet" png shows the normal signal levels.
The "capture_powerline_ethernet" png shows the jump in the noise floor across all of the SW bands, by an amount that swamps most of the broadcast bands. I have a suspicion this one is a SkyQ box misconfigured to use powerline instead of wifi.

The characteristic definer of powerline ethernet noise is the presence of the notches for the amateur radio bands. It's a pity that the current powerline ethernet standard does not force the manufacturers to prevent radiation of noise into the bands used between 5 MHz and 30 MHz, or forces the frequencies used to be above 30 MHz

I wonder if that noise would affect e.g. Tetra transmissions used by the emergency services, and that being a basis for requesting the offender to remove their devices or reconfiguring?

When I receive my loop antenna I'll be able to get bearings on which house is the offender, but until then I'm very thankful that the interference is not beign picked up well on my main randomwire antenna

Has anyone here had success in helping a neighbour in removing this type of RFI pollution?

It looks more like switch mode power supply noise rather than ethernet over powerline.

If you can post an audio sample I can probably tell you right away.

Popoutman

I'm fairly sure that I'm seeing PLC interference, and not switchmode power supplies.
The estate here is built in the 70s, so I'm fairly sure that residents and tenants won't happily string cat5 around a house (even though I did..) and the walls are thick enough that a wifi access point at one side of the house will not adequately cover the room at the other side of the house, less than 10 meters away. I've had to set up one AP each at either side of the house to get coverage through all the rooms up and down stairs. It works great now, and the rest of the occupants are happy enough not tripping over the cable going between the two..

I spent a bit of time recently running every one of my available 5V and 12V power supplies, as well as a few PC power supplies I had to hand. The noise characteristics of the switchmode powersupplies are generally quite broad, and either blurry of border or very fuzzy of border - certainly when into the realm above ~5 MHz at least. When I recently put a badly shielded switchmode supply near the antenna, the noise was randomly across all of the bands, with edges waving about like the arms of a tube man. The noise I'm seeing has very sharply defined attenuation for each of the amateur bands, and only for the amateur bands, between ~5 Mhz and 30 Mhz. Also, it appears that the noise I'm hearing would be consistent with the rates of packets across an idle network, with each burst being an ethernet packet.

I've sent you a link to my Kiwi with examples of where the interfence can clearly be seen. There's RFI all over the WWV frequency at 20 MHz, and none for 100 kHz before the 15m amateur band, and the interference pops up again into the middle of the 13m broadcast band. That attenuated notch edges are not moving, and each burst of RFI has the same rolloff into the amateur bands.

Either way, I'm thankful that the noise is not crippling at the current level, annoying as it is. Hopefully a loop antenna en route at the moment will allow me to null it out.

Antenna

Speaking of powerlines in the more usual sense of the word - travelling the main Cork-Killarney road (N22) - around the border between both counties I experienced massive interference to BBC Radio 4 on 198kHz LW, which was present to varying extents (in areas was complete wipeout, otherwise listenable with annoying interference) for a relatively long stretch of road either side of the county border, coming from 110kV lines from a nearby substation (Clonkeen) which is alongside the main road.

The interference is a powerline telemetry system and this one consisted of a pilot carrier ? on about 200 kHz (200.? ) and immediately above that a hash sounding signal, all within the upper sidebands of BBC R4 198 Long wave.

I have never seen interference effects from powerlines / powerline signaling as bad as this.

Could they not have put this powerline signal on some other frequency than one affecting the most easily heard BBC signal !