1

I have a powerline (Ethernet over power) between two sockets in the house. And it seems to work even when I turn some heavy load (ie hairdryer, washer, etc) to the point even the lights dim for a second... And the powerline does not skip a beat. How does it do that?

user3765743
  • 13
  • 2
  • 2
    Because it operates internally at a much lower voltage and doesn't care. – Finbarr Sep 01 '20 at 17:48
  • Why shouldn't it do that? – Andy aka Sep 01 '20 at 17:52
  • 1
    You have "Powerline" in the title suggesting a brand (proper) name and "powerline" twice in the post indicating an unknown object. Which is it? Capitals matter. Welcome to EE.SE. With regard to the question, how do you know it doesn't skip a beat? You'd have to use something like Wireshark to monitor the network for transmission errors to be confident in that claim. There could be errors all the time that are sorted out by re-transmission. – Transistor Sep 01 '20 at 18:00

2 Answers2

4

First, because communications-over-power schemes run the communications at some frequency well separated from the power line frequency. Dimming the lights for a second is an event that happens in the frequency range of roughly 0 to 120Hz -- your Ethernet-over-power will be running at 100kHz to 100MHz, depending on the scheme.

Second, because it's Ethernet, so when (not if) the equipment on the power line inject some noise in there that interferes with a packet, the network will retry.

TimWescott
  • 46,144
  • 1
  • 42
  • 107
0

Most communication devices and protocols are pretty much adaptive to the changing properties of the media used.

In general, it starts with some extra power on the transmitter side and an automatic gain control (AGC) stage at the receiver. In more sophisticated cases the receiver contains also an automatic equalizer and the protocol allows for negotiating the power used by the transmitter. The protocol may also be able to retransmit the lost data packets invisibly to the upper network layers. That's o

Regarding to the Ethernet over power, you are not changing the media (in the Ethernet sense) properties much by plugging in a kilowatt or two of load. You are (probably) connected to the same power transformer that powers 10 or 100 more households where everyone plugs and unplugs everything as they see fit.

I assume Ethernet over power cannot cross the power transformer because the transformer is profoundly frequency-dependant. OTOH, I have seen Ethernet over power to work flawlessly between houses accross the street. Different Ethernet-over-power networks are isolated by encryption and not physically.

fraxinus
  • 9,184
  • 11
  • 35