PLC devices and troubleshooting home networking

As I’ve been reconfiguring my home network, I wanted to try to get a thorn out of my paw – my home networking woes.

In my last house, I had a basement and it was a single-story dwelling. This meant that I could easily run a network cable to the other end of the house, in the basement – and set up a wireless access point over there. This gave me fantastic Wi-Fi signal everyone in the house and the yard.

In my current house, it is a slab construction which is one story, but it has vaulted ceilings. So, I can’t easily run wires under or over the living space. Also, the outer shell of the house is build with cinder blocks and concrete, and the interior walls are constructed with metal studs.

What are the problems:
To start, my internet connection comes in at my office. So, my main workstation is great. However, using the Wi-Fi built into my Arris router, if I tried to use a laptop or tablet even 20 feet away around a corner, I would basically have an unusable Wi-Fi signal. I’m assuming the metal studs are interfering with the signal.

So, I can’t easily run network cables – which means I can’t easily install other Wireless Access Points (WAP). So I turned to the last resort and set up PLC, or Power Line Communication.

What is PLC?
PLC is the concept of a device that you plug into a wall outlet, with a network cable attached. It will send that Ethernet signal, over your house electrical wiring. This means that you can then plug in a SECOND PLC device anywhere else on your power grid and you can “pick up” that Ethernet signal and host a hub, WAP, etc. in a remote location. A typical PLC device looks like this:


There are limitations and restrictions though. For example, the signal won’t go past a breaker box – and even if it has to go to the breaker box to go back out over another circuit – that alone will degrade the signal significantly.

With that said, the devices I have claim 600mbps speeds, so what could possibly go wrong?

What’s wrong with PLC?
I have spent some time trying to research the problem It would seem that “dirty power” is one problem, and “noise generating” electrical devices is the second problem. Dirty power is unconditioned power that varies widely. Instead of having a steady 120volts, imagine there are constant drops and spikes in power. This constant fluctuation affects the PLC device.

The other issue is when electrical devices cause electrical interference with the Ethernet signal traveling over your house electrical wiring.

Is there any solution?
Well, your first thought might be to put in some type of power conditioner (UPS or surge protector) – but if you plug the PLC into any secondary device (even a power strip), the signal simply doesn’t get out. So although that may work – there is something about power conditioning that also doesn’t allow PLC to work.

The ONLY hint of a solution I found is vaporware called Surestreamer. It’s from a company in Malaysia. It looks to be an inline power conditioner which does NOT interrupt the PLC signal and in-fact cleans up the power so that you get significantly higher bandwidth. They have some videos on YouTube too – but I cannot find any place to buy this product, nor did I find any competitor.

So how bad is PLC?
This is sort of the frustrating part. I get pretty wildly different numbers. It depends on several things like:

  • Are the two nodes on the same electrical segment.
  • How dirty/clean your electricity is.
  • How far away the two nodes are from each other, physically – in terms of the length of electrical wire.

I can only get bandwidth measurements for some connections. I can either run a speed test remotely from that device – to see how fast they can talk to the internet. Or, the PLC WAP’s I have, show you the bandwidth that they detect from the WAP’s to any other PLC device it can find. The WAP’s are managed (with a mgmt website), and the plug-in Ethernet extenders are unmanaged.

So – with all of that said, I made sort of a “map”, below. This is a top-down view of my house, and an out-building out back. I ended up buying a second set of PLC devices because I had such poor Wi-Fi, which I I’m pretty convinced is due to the metal studs in the house.

I fully understanding this is a confusing picture, but this was the best way I could represent it. I have 4 of those PLC adapters that plug into the wall and offer Ethernet, and I have two PLC wireless access points (in addition to the main WAP near the “Main Connection”, but not pictured). Here is the various bandwidth speeds I’ve recorded:


This confusing explains why I’ve been so confused about my home network – I would get REALLY good bandwidth (70-127mbps) over wireless and wired, but I also saw 5mbps.

Why is this?

It’s because of how the house is wired. Where you see 71mb, 127mb, those are likely on the same circuit, and then that goes back to the breaker box. But if you wanted to go from the top WAP to that middle PCL (where you see 5mb) – that likely means that the signal has to go all the way back to the breaker box, across the bus bar (see here for how a circuit breaker works and how it’s wired) and then back out another circuit. That very long trip degrades the signal. That is my best guess on what is happening.

Put another way, every other PLC location needs to go THROUGH the breaker box to get to the “Main Connection” which means I can never get great bandwidth, using this technology.

What’s the bottom line for PLC?
I’ll say what everyone else says – use it if it’s your last resort.

On devices that claim to support 600mbps, I consistently see bandwidth of 5mbps to a max of 127mbps.

If you have ANY other alternatives, choose that – with hard-wiring being the absolute best option.

Wait, so how did I fix my problem?
Well, I may have fixed two problems. I took a closer look at how my modem/router serves Wi-Fi – and compared that with how my remote PLC WAP’s serve up Wi-Fi. I made a point to make sure everyone is broadcasting on different channels. It also turns out that only a couple of  devices can connect via 802.11a or n – so I just created a separate SSID for that, and that runs at 5GHz.

Bottom line, I made sure there was no overlap of my Wi-Fi signal. Now, 802.11a/n clients get 80mbps which isn’t bad. 802.11b/g clients get 25-35mbps which is reasonable too.

Posted in Computers and Internet, General, Infrastructure, Uncategorized

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