Monday 7 April 2014

Powerline Ethernet

 Hello once again, sorry for not posting more regularly, as usual I have quite a few projects I should/could post, so will start with this one.

After moving house recently the new battle to 'tech-up' the house took place. I had various goals and needs to fulfil fairly quickly after moving. The first and primary being, how to get the TV systems working again. As many of you will know I use XBMC and TVHeadend on all TV sets, so each TV needs network access to be able to access the TV systems we use (DVB-T and DVB-S over ethernet). In the old house, I had managed to pipe network cables around from the garage pretty well, as I had a duct up into the loft-space from the garage and could then reach all of the rooms I needed.

However, our new house having a 3rd floor stopped all of this, no loft space that could access each bedroom, no easy link between garage and the rest of the house (The garage was not separate from the house, but there were no obvious ducts/cable runs, etc, between the two, only a power socket). My first thought was WIFI (I've not had much luck with HD over WIFI, but it might work!), so setup my wifi router in the garage (where the servers, TVHeadend live, etc) and started to see what the signal was like. Bad news, the house was built with good thermal insulation (read - tin foil) and so signal was next to non-existant even beside the wall where the WIFI router was setup, so looks like that was out. I then started to think how to cable at least one location and run everything from there, naturally I didn't really want this as did not want to start modifying a brand new house! So I turned to powerline ethernet. Not something I'd used before, but had played about with it at work as a trial, and it seemed pretty good.

I did some reasearch on Powerline Ethernet (Or Homeplug as its sometimes called) and found there are lots of different manufacturers licensed to it, but they all use the same standards pretty much so seem compatible with one another. I looked up the different speeds, and types. My theory being, the higher the stated throughput of the units, the higher chance of it working at HD video that I needed (I'd guestimated up to 30Mb). I found the TP-Link products and that they were on various deals at the moment.

I settled on the TP-Link PA411KIT AV500 which are the 500Mbps twin pack, for around £35 from argos, which is a bargain really for the potential these things had. A few initial observations though, just to be wary before you rush out to buy them!

They are quite stylish, in a white/grey casing and pretty small too (around the size of a regular wall-wart). They have one button on them for security/pairing, 3 LED's (power, powerlinethernet, ethernet) and an RJ45. Here was the first odd thing, its was a 10/100 network port. But the adapters are supposed to do 500Mbps, so why only a 10/100 not giga? After reading, the 500Mbps is as usual a bit misleading, they mean total, so 250Mbps is actual throughput (when in full duplex), but even so, we're still not at 10/100. But then there is the loss of the whole system, generally this can drop you down quite a bit.

My initial testing was very good. One in the garage plugged into my server/switch. One in the living room (Do not plug them into multi-ways, or adapters as it does affect them. I managed with a 2/3-way direct wall plugged splitter for power. If you have to, just make sure it doesn't have surge filters, etc, as those degrade the signal terribly). Doing that I was getting great results, TV streamed fine, as did HD content and all as fast as I needed. So I went out and bought another pair, plugged these into the TV's upstairs in two bedrooms. Again, these worked great, streaming TV was no issue, internet was fine, etc. So I went out again and bought another 2! (These things act almost like a small switched network, very neat). Now depending on what you read maximum is either 6 or 8, so I should be fine. Plugged them in and all did appear fine.

For a few days....

Then it started slowing down, I was having problems with HD content, it just stuttered after a few seconds (basically filling the xbmc buffer and emptying it again). I was also starting to get occasional stutters from SD content, network traffic was slow, etc. So really not good news. I was worried. Was the technology just not that good?

Troubleshooting involved unplugging all the homeplug adapters, so I just had one in the garage and one in the living room. No difference. I updated their firmware, and setup the network to be on my own named instance (By default you pair them and they use their own 'network name' and security), and ensured they were all set the same. Using the TP-Link windows utility it also showed the throughput available to each device, which worried me. They started to show 11Mbps to a few adapters. Depending on which one I plugged into it showed different ones with 11Mbps. So that made me think, what has changed, something has degraded the powerlines and caused this to happen.

I started to read up on the technology, to see what affects it. Seemingly everything! Just going between different phases or breakers in the fuse box can degrade it (Yep, mine was on different breakers). Different floors of the house as they tend to each have their own ring-main (Yep, mine on different floors). Long distances (Possible, I'm not sure what the length of cables, etc, around the house were, so unsure if sockets were say at the start of the ring or the end). Other interference (Yep, I use X10 and setup an X10 house alarm system, which I know uses powerline technology for their control signals).

So I was starting to worry, had these only worked when we moved in, since nothing else in the house was connected at that time. Next stop, I read that many devices cause interference. Biggest culprit, those cheap mobile phone chargers, computer PSUs, Laptop PSUs, basically anything that was a switch-mode power supply.

My next step of testing was to start switching things off and testing. So I began again with just the two TP-Link adapters plugged in, living room and garage. Loaded up an HD video and sat watching it jump and stutter. I then went round and unplugged all of the mobile phone chargers (wow, we have loads of them, at least 2-3 per person in our house!). Still no different, video stuttering. I then unplugged one laptop, no difference. Then my laptop, and it stopped. The HD video suddenly jumped back to life and ran. I let it run for a good 10 minutes and without stutter. Switched my laptop charger back on, almost the second I did, stutters came back. Aha! This was it. Plugged all the other stuff back in (except my laptop) and it was fine. So looks like that was the problem. Thinking back, this was a replacement PSU for my laptop, and was a cheapo copy, not manufacturer, so that would explain it! Cheap and nasty electronics in there caused it. So now I wanted to fix it, so I could use my laptop. I grabbed a surge protected multiway, and tried with that on a different wall socket, and hey presto that worked! So I still have my laptop, and my powerline ethernet works great!

I hope this maybe helps another individual who wants to use this and has interference problems, etc.

I have to say, I'm a big fan of these units, they are impressive units and do a very good job. At some point I'll run some speed tests and see what I can actually get out of them now, but for now they're streaming my HD tv great.


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