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By LEO SIMPSON Fast Ethernet connections via 230VAC mains Is your WiFi router not good enough to run your smart TV? That’s a common problem and the one effective solution is to have a direct Ethernet connection from your modem/router to your TV. But there is now another way and that is to use Ethernet power line adapters. These will let you have an Ethernet connection anywhere in your home. F OR MOST PEOPLE, a WiFi router in their home gives effective wireless connection to their laptop and tablet computers, smart phones etc. But WiFi is not always effective for connection to a smart TV. While the TV may well be able to “recognise” the WiFi connection, it will simply 76  Silicon Chip not be reliable or fast enough to allow video services such as iView, SBS OnDemand, Netflix, Bigpond movies and a host of other internet video services. I have two smart TVs in my home (Panasonic and LG) and I went through a lot of frustration trying to get them to work properly over WiFi. It is hard enough to go through the tedious initialisation process to get the TVs to actually communicate and recognise the connection but getting reliable video transfer is another thing entirely. With my two smart TVs, it simply did not work, even if the modem/ router was in the same room as the TV. siliconchip.com.au So much for smart technology. I contacted one of the engineers at Panasonic and was told that the only guaranteed method of feeding internet video to a smart TV was to have my home wired for Ethernet. Because of the cost and awkardness of doing this, I put this off for quite a while but eventually relented as my wife was keen to watch iView etc. It involved running cables in and through cavity walls for a considerable distance, under floors, over and under lintels for a door and window in a cavity wall and quite a lot of cursing, as I and the electrician persevered with the task. Because I wanted to be able to run the modem-router in either my study or a more centrally located under-stair space in my house, I broke the long cable runs and had a patch panel installed in the under-stair location. At the end of it all, I had reliable Ethernet communications on the ground floor of my house (and my wife could happily view services such as ABC’s iView and SBS On-Demand). But I still had to rely on WiFi if I wanted to use my laptop etc on the top floor or basement workshop. That was OK until WiFi’s speed limitations became apparent. Because my large house is of double-brick construction with a massive concrete floor for the upper section, even an undemanding WiFi connection can be quite The Edimax HP-5101K Nano Power Line Adaptor kit makes it easy to create a 100Mbps Ethernet link between any two power points in your home or office. It sells for just $99 and is available from Jaycar stores (Cat. YN-8352). difficult – that is why I wanted the alternative locations for the modem. So I just had to live with that. There was no way I was going to extend the Ethernet cables to those floors. It was just too difficult to consider, with concrete floors and more cavity walls to be penetrated. Fast Ethernet over power. Within the last 12 months or so, another way to make reliable high-speed Ethernet connections has become available – Ethernet over Power Line. Now Ethernet over Power Line is not new but this latest iteration is really fast at 500Mbps. This is much faster than the 6Mbps (or so) rate required for on-line video services such as iView. Jaycar has just such a product with the Edimax HP-5101K 500Mbps Nano Power Line Adaptor kit. This essentially consists of what look like two identical plugpacks, each with a standard Cat5 socket on the underside. You plug in one close to your modem/ Ethernet Over Power Lines: How Does It Work? Ethernet over power lines is nothing new. We reviewed the NetComm NP210 in October 2005 but a lot has changed since then. For a start, those devices were capable of a maximum speed of 14Mbps which is slower than ADSL2 let alone a proper wired Ethernet link, which these days is usually 1000Mbps (Gigabit Ethernet). The new standard, with up to 500Mbps, is much more competitive and fast enough to copy large files from computer to computer. But they’ve also done a lot of work to ensure interoperability between different brands of Ethernet Over Power adaptor and ensure that interference is not an issue, even if your neighbour is also using such devices. The relevant standard is IEEE 1901, published in 2010. Compliant devices use one of two signalling techniques, siliconchip.com.au either FFT or wavelet-based orthogonal frequency-division multiplexing (OFDM) modulation. While not a requirement of the standard, most good, modern Ethernet Over Power adaptors should support both techniques and thus you are not required to stick with a single brand or model to get connectivity throughout your home or office. OFDM is in fact a similar scheme to that used for ADSL, WiFi and terrestrial digital TV (DVB-T). Data is transmitted on multiple different frequencies simultaneously, with the carriers all being orthogonal to eliminate crosstalk. These devices typically use a signalling frequency in the range of 2-68MHz. On top of the OFDM, IEEE 1901-compliant Ethernet Over Power adaptors implement an “Inter-System Protocol” which allows units to discover other nearby networks that could potentially conflict and share the available bandwidth between them in order to prevent interference from affecting reliability. Essentially, the way that this works is that adaptors periodically broadcast a signal along the power lines indicating their presence. Other adaptors pick up this signal and then negotiate for a time slice during which they have dedicated use of the available bandwidth. In other words, they co-exist by means of a timedivision multiplexing (TDM) scheme. The same protocols can also be used for long-distance signalling, ie, Broadband Over Power Lines but we remain sceptical as to whether this is a practical proposition, especially with regards to interference, both between customers sharing the same power lines and with the power lines radiating RF and possibly interfering with other wireless devices. June 2014  77 Ethernet Over Power – continued router and connect it with a short Ethernet cable. Elsewhere in your house, say behind your smart TV, you plug in the other Power Line Adaptor and connect it to your TV with a short Ethernet cable. If the modem and your TV are both powered up, the lights on the adaptors will immediately indicate that you have a viable Ethernet connection and you are ready to go. It’s that simple. RF interference I was concerned about RF interference from the data being superimposed on the 230VAC mains wiring in my home and went around with a radio on the AM & FM bands but could find little evidence of it. Indeed, there was far more interference from my cordless phone system and to a lesser extent, from the Ethernet cables themselves. The frequency bands used for the data transmission on the mains wiring are from 2-28MHz and 30-66MHz, ie, slap bang over the shortwave bands. A shortwave receiver indicated low interference from the mains wiring when the adaptors were in idle mode but interference is severe when data is being transferred. This will be a problem for anyone who wants to use the shortwave bands. Of course, to use the Nano Power Line Adaptors you really do need to have them powered all the time, as well as your modem/router. But their power consumption is low, about 500mW each on standby (for a total of 1W) and up to 2.4W each at full load. That compares well with my Bigpond modem/router which pulls 6W and gets quite warm into the bargain. I did a comparison of the download rates for on-line video for both my Ethernet connection and Ethernet via the Nano Adaptors. The result was the same at 6Mbps which is probably limited by my ADSL2 connection. That is far below the limit of the Nano Adaptors 100Mbps ports. Then there is the cost comparison. Having the Ethernet wiring installed in my home was quite expensive, requir- ing a substantial amount of Cat6 cable, various Ethernet wall panels and most of all, the labour cost for the electrician. It all came to about $500 and even then it wasn’t a complete solution. On the other hand, a pair of Nano Adaptors means that I can have Ethernet virtually anywhere there is a 230VAC power point; even in the garage or store-room. I will just leave one Nano Adaptor permanently connected to the modem/router and the other can be moved from room to room, as needed. However, since the cost of the Edimax kit, with a pair of adaptors, is just $99, you could easily justify having two or more pairs permanently set up in your home, wherever you might need to have Ethernet for high-speed file transfer or whatever. Overall, I wish this product had been available at the time I had the Ethernet wiring done. It would have saved a lot of time and expense and ultimately, would have been a more complete solution. The Edimax HP-5101K 500Mbps Nano Power Line Adaptor kit is available from all Jaycar stores and resellers SC (Cat. YN-8352). Radio, Television & Hobbies: the COMPLETE archive on DVD YES! NA R MO E THA URY N E T QUARTER C NICS O OF ELECTR ! HISTORY This remarkable collection of PDFs covers every issue of R & H, as it was known from the beginning (April 1939 – price sixpence!) right through to the final edition of R, TV & H in March 1965, before it disappeared forever with the change of name to EA. 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