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Does powerline networking nuke radio hams?

Posted on 10 Aug 2009 at 19:18

Paul Ockenden upsets the amateur radio community by plugging powerline networking

Regular readers will know that I’ve written several times over the past few months about powerline networking – that is, running part of your home or office data network over your mains electricity wiring.

In particular, I’ve written about the success I’ve had with HomePlug kit (both the older HomePlug 1 devices and also the newer HomePlug AV standard), and how I’ve become a great fan of this technology. However several readers have emailed to castigate me for recommending these powerline networking products.

These emails spanned the full spectrum from sensible and rational through to green ink and CAPITALS, but what they all had in common was that they came from radio amateurs, or people with an interest in shortwave radio. They claim that HomePlug kit affects their hobby in much the same way that urban lighting affects amateur astronomers, but rather than causing light pollution it seems that powerline networking causes radio pollution in the HF band (otherwise known as shortwave).

To make matters worse, this RF pollution apparently isn’t restricted to a particular narrow broadcast band; in order to get maximum range and throughput, these devices splatter bits across a wide range of frequencies. At least these were the claims I saw from readers’ emails.

A number of YouTube videos demonstrated HomePlug devices that killed shortwave radio reception


After extensive Googling I found lots of forum and blog posts from shortwave radio enthusiasts complaining about these mains networking devices, with certain factions of the Radio Society of Great Britain (RSGB) also singing from the same hymn sheet (although I did find the document which claims that for most shortwave users with a good setup, the effects should be marginal). I also found a number of videos on YouTube that demonstrated HomePlug devices that completely killed shortwave radio reception.

Lack of complaints

I was somewhat confused, though, because despite finding lots of protests, I struggled to find many complaints from people who’d suffered these kinds of problems because of their neighbours’ powerline networking. In most cases, interference was reported by people who had installed devices in their own house and had found this to compromise their own shortwave radio reception. Maybe I was just using the wrong search terms.

Among other things that my Googling uncovered was that the HomePlug Alliance (the industry body that defines the HomePlug specifications and certifies the various devices) had worked with the American Radio Relay League (ARRL), which is essentially the US counterpart of the UK’s RSGB, to “notch out” the most commonly used ham radio bands from the HomePlug spec.

As a result, it would seem that, unlike in the UK, the US radio community is reasonably happy with HomePlug, but less so with other mains-borne data technologies, particularly those delivering broadband-over-power-lines (BPL) to the home or office, which tend not to have the amateur bands notched out. These technologies aren’t really being much used in the UK at the moment, apart from in a few trials.

It seems the notches cover only the bands that radio amateurs use to talk to each other, not those used by long-distance broadcasting stations, so even the ARRL-approved HomePlug devices are causing concern to some enthusiasts.

Another thing that Googling revealed was a handful of forum posts where people were complaining about interference from, rather than to, radio enthusiasts. Apparently, if the person next door pumps out 1.5KW of HF radio waves, they can cause havoc with stuff such as TV reception and baby monitors. It seems as though this can be a problem even where the guy next door (and it nearly always is a guy) has a perfectly legal and properly adjusted radio transmitter.

It would appear that, at least from a technical point of view, there are valid arguments on both sides, but even if you ignore these technology arguments, the debate still doesn’t have any clear winner.

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User comments

Enough is enough already - HomePlug is great for Home Area Networking

Does anyone actually have a Ham radio nowadays that is actually being effected by someone's HomePlug device? -- Or is this just some hypethetical argument nowadays. Progress with BPL may have limited collateral damage, but the benefits outweigh the rare problem. What's the alternative? ZigBee? That sure plays havoc with your 2.4 gig cordless! Go figure.

By Negawatt on 12 Aug 2009

Undoubtably, yes

Most, if not all, power line networking equipment currently on sale is illegal [http://www.compliance-club.com/PLT/Tim%20Williams
%20EMCJ%20Issue%2080.pdf] because it does not, and cannot meet the essential requirements of the EMC directive, ie it causes interference with short wave radio.
http://www.compliance-club.com/PLT/Tim%20Williams%
20EMCJ%20Issue%2082.pdf

Industry EMC Experts have written the EU about this [http://www.compliance-club.com/PLT/EU-submission-
ADDX-01%2030%20sept%202003.pdf] and recieved the brush off [http://www.compliance-club.com/PLT/EU-submission-
ADDX-02-answer%2013%20Nov%202003.pdf], quoting commercial concerns above technical ones. We will soon get to the stage, similar to what happened with in car iPod to FM transmitters, where the authorities allow this flagrant disregard for compliance with existing legislation because there are now many of them in service and it is too late to do anything about it [http://www.compliance-club.com/PLT/EU-submission-
ADDX-06-answer%206%20Aug%202004.pdf].

By martincowen100 on 13 Aug 2009

PLC is a very poor idea

You really ought to read RTO Technical Report TR-IST-050 from the NATO.



The use of broadband powerline communication is imho more than just merely wrong.

By ethseths on 13 Aug 2009

Illegal, and a cop-out

What exactly is wrong with either Wi-Fi or Cat 5 cable?

I'm in an area with heavy cable take up - and as a result, zero takeup of BT Vision. I'm fortune enough to not suffer from PLT interference.

I bought a pair of Comtrend PLT adaptors at a car boot sale so I could experience it first hand (and demonstrate it to other amateurs), and also so noone else would use them!

The fact is - ANY mains wiring will act like an aerial, making any 'live' PLT device an illegal radio transmitter.

I applaud you for being the first in your line of work to bother to investigate this. However - you are right that Amateurs will use more sensitive equipment than your Sony - however, we will also be looking for much lower level signals than broadcast stations too.

Radio Bulgaria, which I listen to often, has a signal level of S9 + 40dB here, whereas some of amateurs I have had two-way contact with have had a signal level below what the meter can show!

With the Comtrends plugged in anywhere in my own house, the noise level from them (even at idle) is never below S7.

There's better out there than PLTs, and there's no real excuse for them existing, other than laziness of the user and greed from the manufacturer.

By Ayrshore on 13 Aug 2009

PLC Home Plug radio interference

Paul.
I appriciate your article here about this issue, and I assure you that many radio amateurs and shortwave listeners around the world are very concerned about this. There are currently around 65.000 licenced radio amateurs in the UK and also a large number of shortwave listeners and to dismiss them would be wrong. One fact is that HomePlug are only a replacement for a CAT-5 wired data network and one argument is that most people can in fact manage to use CAT-5 cable and a small switch. I also believe that the transfer rate with CAT-5 cable network are better than HomePlug. Using CAT-5 cable and a switch solves the problem. Read what "Martincowen100" refers to above. My test with Devolo HomePlug units can be found at Youtube, search for "PLC Home Plug radio interference". I have sendt my protest about HomePlug units to the Norwegian Post & teletilsyn (similar to Ofcom in UK) and asked them to deny import of units that does not comply to the EN55022 EMC standard. That would in fact mean all HomePlug units. Read "RF emissions of Powerline Ethernet adapters» by Tim
Williams, Elmac services to see what kind of severe problem this is.

By rdehli on 13 Aug 2009

PLC Home Plug radio interference

Paul.
I appriciate your article here about this issue, and I assure you that many radio amateurs and shortwave listeners around the world are very concerned about this. There are currently around 65.000 licenced radio amateurs in the UK and also a large number of shortwave listeners and to dismiss them would be wrong. One fact is that HomePlug are only a replacement for a CAT-5 wired data network and one argument is that most people can in fact manage to use CAT-5 cable and a small switch. I also believe that the transfer rate with CAT-5 cable network are better than HomePlug. Using CAT-5 cable and a switch solves the problem. Read what "Martincowen100" refers to above. My test with Devolo HomePlug units can be found at Youtube, search for "PLC Home Plug radio interference". I have sendt my protest about HomePlug units to the Norwegian Post & teletilsyn (similar to Ofcom in UK) and asked them to deny import of units that does not comply to the EN55022 EMC standard. That would in fact mean all HomePlug units. Read "RF emissions of Powerline Ethernet adapters» by Tim
Williams, Elmac services to see what kind of severe problem this is.

By rdehli on 13 Aug 2009

USA Powerline networks (BPL) problem

Paul.

In the USA the ARRL (American Amateur Radio Leauge) has taken court action to deny internet via power lines. See this link:
http://www.youtube.com/watch?v=mdoRW39smDc

As long as the PLC/PLT/BPL uses HF frequencies to transfer data via unshielded mains wiring there will be radio interference problems. The problem with mains wiring cables is that they are designed for 50Hz and not HF or VHF frequencies. Also, the impedance load is unpredictible because of different cable lenghts, switches, connected apparatus etc etc. CAT-5 cable are twisted pairs because two wires running opposite currents in 180 degrees phase will cancel out RF radiation. Also, the impedance load is designed to fit the connected units. This is the only correct way of making a wired data network when it comes to good RF-design.

By rdehli on 13 Aug 2009

What about the emergency sevices?

Don't forget there are search and rescue / coast guard services that cannot use VHF or UHF so well or reliably or the military who need reliable long distance comms, where no alternative can exist. Lives WILL be lost because an important message cannot be heard in-land because someone wants there illegal copy of windows or the latest album.

I can't see what the issue is with CAT5 cable - I have just run more than 100M for someone and it suffered no loose in signal, created no interference to me and everyone was happy - so why not others?

It's also demonstrating there is a 2-tier system here, we have bend over backwards for as long as radio and television to ensure our signals don't interfere with your equipment, but it's considered acceptable to allow your illegal devices to interfere with mine, just to allow your illegal downloads to continue?

By DS___ on 13 Aug 2009

The law is very clear on this. No device shall cause harmful interference, or prevent other devices from working as intended. That's the line, and these things crossed it long, long ago. Notching the amateur bands might keep some amateurs happy in a country like the US, where your neighbours might be some way away, but our experience over here in the UK has been a much raised noise floor, even on the 'notched' bands.

Amateurs and Short Wave Listeners aren't always visible by large antennas. Some have them in the loft space. Besides, the hash from these things has been known to go over a half-mile, in one case, being caried by overhead woring to the next village.

An old, blind listener not far from me had his harmless lifetime hobby destroyed the moment someone 300 metres away innocently plugged one of these accursed things in. This isn't mentioned just to take the moral high ground. The question is whether a technically illegal device that's not even an enabling technology, just one of convenience, is worth allowing to continue on the market given the problems it causes. A good new technology wouldn't need a valid, reasonable law to be broken and ignored, or an existing, proven technology to be vandalised.

Short wave broadcasters, such as the BBC, Deutsche Welle and many others, are investing in DRM, a new digital broadcasting format that delivers near-fm broadcast quality stereo sound via the shortwave bands, so they intend to be around for a long time yet. The people listening to them will be, too. Do everyone, including yourself, a favour. Get a wifi dongle or some cat5 cable.

By Astra on 13 Aug 2009

Good points everyone

Thanks for the feedback on the column folks - and thanks for keeping it fairly sane and level headed, unlike some of the emails I've received!!!!

One point I would make is that Wi-Fi or Cat5 isn't always a solution. Indeed, in previous columns, the time when I've advocated using HomePlugs is when Wi-Fi won't/can't reach, and when cabling simply isn't an option.

In places where running cables is easy (cavity walls are great for this, provided the gap hasn't been filled with rockwool) I'd always advocate doing that over using HomePlugs. I hope I've always made that clear in my previous columns. I really see HomePlugs as a "when nothing else works" solution.

Another point that I raised in the column but which no-one has responded to yet is that surely the Internet brings distant stations to you much more efficiently than a shortwave setup ever will. And for those doing two-way DX contact isn't something like Twitter or Email a better option?

I know that question might sound like heresy to some of you, but from a complete outsider's point of view one might argue that keeping the HF bands clear for low signal communication is a bit like keeping the rail tracks clear of fast express trains so that nostalgists can run steam trains over them.

So, ignoring the "is it legal" angle for a minute (if you're able to), what do you think of the argument that progress sometimes has a price, and that in this specific case, what radio amateurs seem to want to preserve can often be done much better, cheaper, and more efficiently using Internet based technologies. Can we have a rational discussion about that?

And please - I'm not spoiling for a fight here - I'm really and genuinely interested to know the arguments from the other side of the fence.

Cheers,

Paul.

By PaulOckenden on 13 Aug 2009

Things you need to know

Paul,

You refer to interference
from Radio Amateurs,when this occurs the ham is not
transmitting on the same
frequency as the complainant,so given patience,sometimes sadly lacking,the problem can be
cured by filtering.

In the case of PLT these ARE transmitting on the same frequencies so cannot
be filtered without at the
same time preventing the PLTs from working.

Having suffered from PLT
Interference had to involve Ofcom ,4 BT Vision
Installations were involved,3 were direct wired and one was replaced
by WiFi.
These were at distances up
to 250 metres from my house.
I was affected by a 5th installation but this went
out of use for unknown reasons.
Had I not complained several thousand Pounds worth of modern equipment
some employing digital processing technology would have been rendered
useless,is this what you
call legacy technology?

Perhaps you would care to
look at www.theemcjournal.com
to see more about this subject.

Many programmes broadcast
on HF radio are not availiable on the Internet
and quality will be improved by DRM broadcasting if PLTs dont
blot it out.
I tested both the HPA and
UPA types in 3 of my neighbours houses,one 80 meters away,all caused considerable interference.
The Comtrend HPA type as used by BT Vision are much worse as they generate noise 24/7,independant of data rate.
Please note I am using good radio frequency practices in my installation as you might
expect from a former Broadcast engineer.

These devices have been
marketed regardless of the
consequences of their use and bring radio listeners
and mains networkers into
unnecessary conflict and the increasing number of
Official complaints to Ofcom have put them to a lot of trouble dealing with what they call Spectrum Abuse.
Radio listeners are reluctant to make a complaint to the official
regulator Ofcom but you can be sure these will increase.

By paulfw on 13 Aug 2009

HomePlug radio interference

Paul.

Yes, we all love the Internet, but we dont want to buy boxes that makes our radio receivers useless at the same time. There is no need for this kind of conflict, but bad decisions from the authorities has made this happen.

In those cases where 2.4GHz Wifi and CAT-5 cabling are not an option (I cannot see that CAT-5 can not be used almost everywhere?) would 900 MHz Wifi maybe be a solution ? It has after all much higher ability to penetrate walls etc. than 2.4 GHz. Transfer rates are limited to around 1.5Gbit/sec though, but may be suficcient in many cases. More info at: http://www.avalanwireless.com/assets_v3/product_br
iefs/AW900i_Product_Brief.pdf
and: http://www.caworldwifi.com/900-Mhz-WiFi.html
Rather hefty prices though.

By rdehli on 13 Aug 2009

What happens when the infrastructure fails

I know of a 22-year old who is working in electronics because of his interest in shortwave radio. Another at 16 got his foundation ham radio licence and this helped when he applied to do comms in the army.

When the twin towers came down on 9/11, they took much of New York’s comms with them, and the only emergency radio links were provided by radio hams. Similarly when the tsunami hit islands in the Indian Ocean, radio hams were the only ones able to set up stations and pass life-saving messages. Closer to home, radio amateurs are part of each county’s emergency planning, and often participate in events usually through an organisation called Raynet.

If PLT renders the shortwave spectrum unusable, which it threatens to do, then a pool of skilled and committed radio operators will be lost forever. Don't assume that the internet or cellphone network will always be there. You may need radio hams to pass messages in times of emergency.

Even without these justifications for what some may see as a ‘legacy’ hobby we should not tolerate widespread pollution of the shortwave spectrum. Suppose a new networking technology were invented that used the river and canal network. It delivered high-speed data, though no faster than existing technologies such as fibre, but had the effect of turning the water purple and killing all the fish. Do you think such pollution would be tolerated? Of course not. We cannot see it, but shortwave frequencies are being polluted just the same by PLT.

By Dave_L on 13 Aug 2009

HomePlug radio interference

Correction:
That would be 1.5Mbit/sec. not 1.5Gbit/sec.

By rdehli on 13 Aug 2009

Re Infrastructure

It is worth while thinking that with SW Radio you actually have a freedom to listen to views which may not necessarily sit well with the government (whatever the colour), Internet access can easily be controlled, just look at what goes on in China. Our current government likes to be in control...

By Tim100 on 13 Aug 2009

What happens when the infrastructure fails

I know of a 22-year old who is working in electronics because of his interest in shortwave radio. Another at 16 got his foundation ham radio licence and this helped when he applied to do comms in the army.

When the twin towers came down on 9/11, they took much of New York’s comms with them, and the only emergency radio links were provided by radio hams. Similarly when the tsunami hit islands in the Indian Ocean, radio hams were the only ones able to set up stations and pass life-saving messages. Closer to home, radio amateurs are part of each county’s emergency planning, and often participate in events usually through an organisation called Raynet.

If PLT renders the shortwave spectrum unusable, which it threatens to do, then a pool of skilled and committed radio operators will be lost forever. Don't assume that the internet or cellphone network will always be there. You may need radio hams to pass messages in times of emergency.

Even without these justifications for what some may see as a ‘legacy’ hobby we should not tolerate widespread pollution of the shortwave spectrum. Suppose a new networking technology were invented that used the river and canal network. It delivered high-speed data, though no faster than existing technologies such as fibre, but had the effect of turning the water purple and killing all the fish. Do you think such pollution would be tolerated? Of course not. We cannot see it, but shortwave frequencies are being polluted just the same by PLT.

By Dave_L on 13 Aug 2009

A few more things you need to know

When tested in my small house the PLTs only worked
on some sockets.
Mains spikes makes them
lock up,only cured by
switching mains off and on.
These things can reduce your Internet speed in some installations.

Each adaptor uses 5 watts
about 2 watts if on standby

By paulfw on 13 Aug 2009

Its not just radio hams

Paul,

You phrase your question as if its Internet or Shortwave radio.

Unfortunately, that's not the choice - since these PLTs transmit wideband interference over one thousand times the levels that all electronics is tested against, any other electronic device in the vacinity may well suffer from performance problems such as lockup, resets, data corruption and so on. If the EU allow the PLTs to exist, they would logically have to increase the immunity tests that all electronics has to withstand by a lot, which would either force a lot of current products off the market or make them more expensive. Such increased immunity requirements could well put an end to the current run of cheap computing and hi-fi gear as we know it.

By martincowen100 on 13 Aug 2009

Better solutions than PLC

It should not be nescessary to have these kind of devices that blocks already existing services and ruin peoples hobby. The correct procedure is to test electronic devices and make sure they do not disturb other equiptment. EMC control inside EU and other countries are poorly handled these days. I believe these HomePlug devices will receive more and more complaints about radio interference and eventually be banned. If they could come up with another type of technology that does not cause radio interference we would all be very happy. I would recommend wired CAT-5 networks where ever it is possible, or use two or more Linksys 2.4GHz Wifi WRT54GL routers running DD-WRT in repeater mode for extended range.

By rdehli on 13 Aug 2009

BPL can reduce your broadband speed!!

Have you checked your broadband speed since installing powerline adaptors?

There is evidence emerging that the powerline adaptors also interfere with your broadband, especially if you have overhead telephone wires!!

Check your speeed with BPL then check again with them unplugged. You might change your mind about powerline technology after this!

By G0RSQPeter on 13 Aug 2009

What after BPL

These devices exceed the current interference limits by a factor of 1000 times!!
This is fact and un-challenged.
The current law on interference is being ignored for political and comercial reasons.
What will happen next when other companies realise that they can ignore international law on interference?
Why should they bother to waste 100's of thousands of pounds testing and conforming to interference regulations. Some electronic manufacturers, particularily far eastern countries, will flood the market with equipment that has no consideration for interference, and these will interfere with your BPL devices rendering them useless.
Already computer PSU's, Wall-Warts and many other devices are comming on the market with their expensive mains filters removed, and these will put more interference onto the mains stopping your PLT from working!

By G0RSQPeter on 13 Aug 2009

Lazy people piss me off!

Though not a ham I do understand where they are coming from on this one. I also find the devices that are sold to network over PLs to be of dubious usefulness and limited performance. Having been in the networking business for a few years doing it in both commercial and residential I can say that there is not one compelling reason to not use UTP for networking. In some limited cases WiFi may be called for. I have yet to see poor performance from this technology due to crowded spectrum. Wire is cheap and there are plenty of enthusiast out there that are willing to help others put in a proper network. Just ask them and find out. I am even willing to bet that most hams will chip in to keep their area free of interference.

Mike

By mikeiver on 14 Aug 2009

If you really want to stop people using them...

Wow, you really seem to have stirred up a vertitable hornet's nest of radio hams. If you really want to stop people using these then all you need to do is hack GNU soft radio, or your choice of software defined radio, so that it can decode the modulation (and for all of you radio hams that really can't be hard) then hook it up to a good reciever and find out the radius in which you can listen to the network traffic.

One good sensationalist scandal article on "OMG homeplug is insecure, everyone within 5 miles can read your mail" (with links to slashdot, digg, wired and every other noise amplifier in the 'blogosphere'), will likely do more to stop adoption than any amount political letter writing.

And yes, I know they are 'supposed' to be encrypted but unless it's on by default I would guess most people don't use it. Plus it will likely be flawed.

Come on all you angry hams - put your skills to use. A bit of careful PR and get the "homeplug is insecure" meme going and problem solved. I mean Windows always crashes and Debian is, like, 5 years behind everyone else, right?

By storm311 on 14 Aug 2009

The other issue

Here in the US the BPL trials were often unannounced which resulted in a lack of complaints in regards to interference. But the other issue that was not covered in the article was the effect amateur radio transmitters have on BPL lines and RF devices in general.

In the US BPL trials, low power amateur radio transmission were able to completely disrupt BPL network connections making the technology essentially useless. Power lines are effectively long wire antennas and will readily pick up HF/VHF/UHF signals.

By EdYUS on 14 Aug 2009

Not Taking Sides

Without taking sides, I'd like to point out a few things.
* In the states, the concerns against BPL typically refer to the technology for last-mile communication, between a power company supplying Internet service and a building. This is useful in many underserved areas where laying new copper or fiber would be expensive due to low housing density. To cover the distance, they also use higher power and the longer lines act as more effective antennas.
* When you count the number of hams, I suspect it would be more fair to include only those who work HF. Many hams stick to VHF and UHF handhelds that would not be affected.
* I've been a ham operator for 20 years, including HF. The philosophy I've been taught is to first try to work out problems with neighbors - be helpful, treat it as a problem to be solved. It's worked well.
* Ethernet over Power adapters have helped me in two situations where in-house wireless and running new cat 5 were not options. I'd hate to lose access outright.

By MartyS on 14 Aug 2009

The point of DX....

"surely the Internet brings distant stations to you much more efficiently than a shortwave setup ever will. And for those doing two-way DX contact isn't something like Twitter or Email a better option?"

Efficiency and reliability are the opposite of what I want when I search for DX. DX is about digging for the weakest signals over the *least likely* radio paths. It's about making a once-in-a-lifetime contact in the context of world-wide radio propagation, not about talking to a far off place.

The argument that the internet is a better way to contact far off points on the globe is quite equivalent to saying to the amateur astronomers you mentioned that their hobby would better be accomplished by poring over Hubble images on NASA's website. Surely they can find each star or nebula they'd like to look at there.

In each case, we do not pursue our hobbies for the end result, we do it for the process and the excitement when we succeed. I understand and appreciate your points about the difficulty of alternative technologies for some folks, but ultimately I feel it is unacceptable to pollute the HF radio spectrum for want of a twisted pair or narrowband microwave emission.

I assure you, the sound of a quiet band with natural static from a long way off is to many radio amateurs very much like gazing into the deep black sky in the wilderness.

Maybe it doesn't matter to you if anyone can do that, but I want to make it clear what's at stake. I don't want to get on Skype and talk to Mongolia, or email Chatham Island. I want to hear them as a barely audible beeping of Morse.

Furthermore, this goes beyond preserving my anachronistic pastime. Notching is a positive step for amateur radio, but does nothing to address the fact that ionospheric propagation is a phenomenon to the HF bands. They require exactly zero infrastructure for worldwide communication. I won't get too high and mighty about emergency communications. In a real emergency, all the homeplugs and BPL installations will go dark. But at the same time, there is nothing else that works like ionospheric HF communications do. Should we really ruin it just because it's hard to run cable or get a reasonable WiFi connection?

By danN3OX on 14 Aug 2009

Rail analogy...

" one might argue that keeping the HF bands clear for low signal communication is a bit like keeping the rail tracks clear of fast express trains so that nostalgists can run steam trains over them."

I think this analogy is a little off kilter. Rails are not a unique natural resource. The steam enthusiasts could probably find commercially unusable tracks to use, and in the end could pitch in and build new ones if they had to.

I think the analogy would mesh better if one express line 1.4 times faster than Amtrak's Acela were installed between Washington DC and New York City, but somehow used ALL the rails that were not otherwise in use in the entire U.S., and would consume all that could be built in the future.

It's a significant convenience for the fairly large number of people who benefit, but shuts out all other current and future applications of unused rails elsewhere.

It may be that the only people who would currently complain would be the steamheads. And the less tactful might do so in GREEN CAPITAL LETTERS. ;-)

By danN3OX on 14 Aug 2009

Other H.F. users?

I have a question for Paul Ockenden: Why does he keep banging on about Ham Radio?

Is he genuinely unaware of the many hundreds of H.F. users besides Ham Radio?

What about the Military, and essential services such as Ambulance, Fire, Police, Marine, Aircraft, or even S/W Broadcasting?

Can he be that technically ignorant, or is he trying to hide the bigger story?

As a professional Communication Engineer, I can tell you that BPL will cause chaos to Essential Services.

By Config on 14 Aug 2009

PLT causes issues

I have recently installed a Cisco Linksys PLT and it's frequencies are causing my television, surround sound and Fios reciever to reset whenever someone uses the network. I am not alone in this problem as others I have talked with are having simular problems especially when surge protectors are in use.

By Rebootmeplease on 14 Aug 2009

PLT causes issues

I have recently installed a Cisco Linksys PLT and it's frequencies are causing my television, surround sound and Fios reciever to reset whenever someone uses the network. I am not alone in this problem as others I have talked with are having simular problems especially when surge protectors are in use.

By Rebootmeplease on 14 Aug 2009

PLC and BPL thoughts.

Green ink and all caps is more a sign of the commentator than of their views, or of their real knowledge of the subject matter. I refer you to the recent misinformation, on both sides, regarding the healthcare debate in the US.

IF you're going to get reasonable Ham Radio technical information, I recommend you talk to Ed Hare at the American Radio Relay League. He's a competent engineer and has done a lot of work following especially the BPL story in the US, with sampling, tests and objective data. The majority of the entities deploying BPL didn't have, want or release objective data. As noted by another poster, they often deployed with no announcement. In those cases, when interference was noted by someone, like but not limited to a Ham Operator, someone had to track it down and identify it. Often as not the power company would deny a BPL installation was in place, even when it could be verified with instrumentation and photographic evidence.

PLC, on the other hand, while it does have the ability to interfere, runs on different frequencies (at least in the US, and I'm not simply referring to the notching) and at lower power levels. It's got a chance of coexisting.

BPL has listened and adapted with the Ham Radio complaints. I've seen installations in Houston, Texas, that were operating their carrier in the VHF spectrum, making them easier to filter, and less prone to interfering with the Hams.

The discussion of essential services and the potential for interference is well taken, and the basis for US Department of Defense, and National Institute of Science and Technology reports castigating BPL. Our DoD were almost as complimentary of the technology as the cited NATO report.

I'msorry. This article was self-serving, poorly researched and camouflaged with quasi-technical investigation. Most of the technical investigations involve and require directional antennas, spectrum analyzers, and either computer-based data capture or photographic images of an analyzer to be considered to have collected objective data. Hooking up your local Sony general coverage receiver, noting the interference, then discounting it completely does not conjure a vision of journalistic competence. Instead, it suggests you need to work with your background researchers a bit more to learn what we scientists do when investigating a problem. Study it.

By GPSGuy on 14 Aug 2009

> surely the Internet
> brings distant
> stations to you much
> more efficiently than
> a shortwave setup ever
> will.

a) Not every station streams in the internet.

b) The internet can be filtered. It is much more difficult to block radio broadcasts.

c) The internet is not available in many places, e.g. most cars, or may not have enough bandwidth, e.g. many rural areas.

d) The internet is more expensive.


> And for those doing
> two-way DX contact
> isn't something like
> Twitter or Email a
> better option?

You can not really compare the two. It is like comparing apples with river deltas... ;-)

By ethseths on 14 Aug 2009

A couple of comments

I notice that many who've commented seem to be in the US. I know that over there BPL is used to actually deliver broadband into the home. But we don't have that here in the UK, and my article wasn't about that subject. I was specifically addressing HomePlug alliance devices. (Even the Comtrend devices used here by the BT Vision system fall outside that scope - they don't have the amateur band notches).

Secondly, for those saying that I should have done more scientific research, I guess you're not regular PC Pro readers. My column sits within the Real World section. It's about experience of using kit in genuine homes and offices, rather than on a lab bench. It's about what happens in practice rather than what happens in theory.

I just thought I needed to make those points because some of you really seem to have got the wrong end of the stick on this one.

Having said that, I am really enjoying your feedback. Please keep it coming - just bear in mind that this is about real world use of HomePlug kit here in the UK, and NOT broadband over powerline kit in the US.

Thanks,

P.

By PaulOckenden on 14 Aug 2009

What exactly is wrong with either Wi-Fi or Cat 5 cable?

To the poster above who asked "What exactly is wrong with either Wi-Fi or Cat 5 cable?"

Well, I don't own the property that I live in, so I can't bore holes in the walls to run Cat5 between rooms. I can't even put in trunking to run it along the skirting board. I also have foil backed insulation on my drywall, which kills most any radio signals (it's like living in a somewhat efficient Faraday cage).

I also know that none of my neighbors are ham radio enthusiasts.

Cat5 and Wifi aren't suitable for us all.

By Perfectblue97 on 14 Aug 2009

Religion?

Reading this debate is like watching a video of Richard Dawkins walking into Finsbury park mosque with a chainsaw and accusing religion of being dangerous.

Move over radical Islam, the ham fundamentalist and the evangelical BPL have arrived. Some serious perspective is needed here.

By Perfectblue97 on 14 Aug 2009

More than just Amateur Radio

As has been touched upon, the HF spectrum is used by more than just Radio Hams.

Search and Rescue, Military, Marine, Air Traffic Control are just a few of the services affected by these devices.

It takes only very low power on HF to travel for a long, long way (10 Watts gets me into Europe every day if I want).

Once coupled to the mains, the signal will be radiated by every inch of the wires it is attached to - making that lampost outside your house a potential 25ft long vertical aerial.

This pair of comtrends I have here completely blot of Shanwick Oceanic control on 5 MHz here - so any plane overflying an area with a few of these things working may temporarily lose contact with ATC for the next leg of it's journey.

The point of radio is that it's completely free of any outside influence or infrastructure. There's no content filter, no traffic shaping, no network to go down.

Haven't you seen Die Hard 4.0? :P The "CB" radio worked even though every mobile phone, satellite phone and internet node was down. It's over the top, yet true - and it was proved in New York on September 11th 2001.

HF is for worldwide comms - not short range. UHF/SHF is for short range.

For those of you who complain that WiFi and Cat 5 isn't an option - you never heard of a Wifi repeater? How big does your house have to be before you can't run a Cat 5 cable?

By Ayrshore on 14 Aug 2009

Serious perspective?

OK, Serious, unbiased perspective coming right up.

"The Electromagnetic
Compatibility Regulations
2006"

Section 4(2)(a) states that no equipment shall prevent radio equipment operating as intended.

This means that PLT devices fail this section, which is known as the "essential requirements" section.

Section 16:
"No person shall put into service apparatus unless it complies with the essential requirements"

This makes it a breach of the regulations to USE one of these devices.

Section 46:
"Any person who places on the market or puts into service equipment in
contravention of
regulation 15, 16, 34 or 35 shall be guilty of an offence."

This makes it an offence to use or sell any device which causes radio interference.

So there you have it - straight from the government - these things are illegal.

Check it out yourself at the OPSI website, Statutory Instrument no. 3418 of 2006.

By Ayrshore on 14 Aug 2009

Please feel free to...

Please feel free to contact the Ofcom Field Engineer who dealt with my PLT claim which you say doesn't exist - alan.holmes@ofcom.org.uk - who spends a great deal of his time investigation BT Vision/Comtrend PLT complaints. If you want more background to my story, visit the following links. First one is for the background and what happened and the last one is for the result.

http://www.transmission1.co.uk/forum/viewtopic.php
?f=2&t=9157

http://www.transmission1.co.uk/forum/viewtopic.php
?f=2&t=9459

By Conor on 14 Aug 2009

You Have Been Slashdotted

Paul:

You just think the complaints about your column have just started. Be prepared to receive a tremendous amount of complaints from the radio-amateur community, with most of the writers having a much higher level of technical competence than you might be accustomed to, dude. This will probably include the engineers and scientist that actually designed the vast majority of the networking and computing technology that you have at your fingertips and use on a daily basis. I'll be very surprised if you server actually survives the onslaught.

73 (Best Regards)

By AB5NI on 14 Aug 2009

You Have Been Slashdotted

Paul:

You just think the complaints about your column have just started. Be prepared to receive a tremendous amount of complaints from the radio-amateur community, with most of the writers having a much higher level of technical competence than you might be accustomed to, dude. This will probably include the engineers and scientist that actually designed the vast majority of the networking and computing technology that you have at your fingertips and use on a daily basis. I'll be very surprised if you server actually survives the onslaught.

73 (Best Regards)

By AB5NI on 14 Aug 2009

Lack of complaints?

"I struggled to find many complaints from people who’d suffered these kinds of problems because of their neighbours’ powerline networking."

Could that be that I do not have the slightest idea that my neighbout is using one of these devices. I all I will know is that i am not reveiving as many signal as I used to as the S/N radio has reduced. That could be due to many things. I personally do not go round my neighbours accusing them of poluting the airwaves because i cannot use my ham radio.

By captaincinders on 14 Aug 2009

Would you know?

captaincinders, you certainly would know. There's a very distinct "digital drumming" noise signature that comes from HomePlug devices.

By PaulOckenden on 14 Aug 2009

Steam rail VS intercity 125

Sorry but that analogy is a bit off.

Possibly more accurate is the following. Imagine the steam railway enthuasists happly pottering up and down for years providing entertainment for scores of family visitors. An intercity route runs next to them to carry all this new exciting commerce and fast convenient travel. For years they happily coexist. Then the steam enthusasts wake up one day to find that, in order to make the maintenance of the intercity line easier, an access road is build over the top of the steam line.

The intercity service has not been improved at all, just made the infrastructure maintenance a bit more convenient, but the steam line has been destroyed.

See the difference?

By captaincinders on 14 Aug 2009

@ PaulOckenden

So now I now that someting 'digital' is causing a 'drumming' signal. What it is, how far away and where it is is all still a bit undecided.

I still do not know it is a Homeplug in one of my many neighbours houses so cannot raise it as an issue and that is possibly the reason for a lack of specific complaints about neighbours using it. That is the point I was trying to maker

By captaincinders on 14 Aug 2009

Captaincinders

Captaincinders, I don't know if you are in the UK. If you are then where have you been?.
It has been well documented both in print and recordings the trouble caused by PLA, you just have to look on You Tube..
Whatever your interference if your noise is of a sufficiently bad level to disrupt your listening OFCOM will investigate where it is coming from.

By Tim100 on 14 Aug 2009

Real world for *HF users* is what matters...

"My column sits within the Real World section. It's about experience of using kit in genuine homes and offices, rather than on a lab bench."

A ham radio station or other HF installation with permanently installed antennas is massively more sensitive than your particular testbed.

Additionally, HF users suffer with massive interference from totally unintentional HF emitters connected to their neighbors' mains. Intentional emitters of broadband data emissions in the HF spectrum will be worse.

The fact of the matter is that connecting an intentional HF emitter to a random network of random length wires, not all of which are differential pairs and which certainly exhibit various resonances, can a recipe for massive, devastating interference. The fact that it is not always that way to each HF user is not sufficient cause to conclude that these devices are fine in the "real world."

Spot checks of people who dump their trash in the woods would probably lead you to conclude that it was fine in the "real world." You could find happy, well fed raccoons and other scavengers. But multiply it millions of times over in more and less sensitive ecosystems and you have a huge pollution problem.

Please recognize that unless you *try* to find a broad cross section of real hams with real HomePlug interference problems and non-problems from real next door neighbors, you have not figured out the real world impact of these devices. The potential for interference is enormous and very variable depending on the matrix of wiring present and the particulars of the HF station with large permanently installed antennas.

By danN3OX on 14 Aug 2009

HF is obsolete

Paul, as a professional radio communications engineer and a ham radio operator and a UK writer of European Standards for security communications, all of my concerns, thoughts, fears and advice for PLT and the BT Vision & HomePlug devices has already been said by others in this column.

To move to a different aspect that has not been answered fully, in your reply on 13 Aug you stated that you wished to discuss: '....what radio amateurs seem to want to preserve can often be done much better, cheaper, and more efficiently using Internet based technologies.....

May I suggest: 'what mountain climers seem to want to preserve can often be done much better, cheaper, and more efficiently using helicopter based technologies'.

A new technology is not always better than an existing technology. New does not mean that old is obsolete. Cheaper and more efficiently are two advantages but they do not 'trump' all of a technology's disadvantages. Neither are new technologies always to the benefit of humanity. E.g. a nuclear bomb.

By Derf1 on 14 Aug 2009

Cat5 and WiFi, I can't use it.

Having never owned a house or apartment I can sort of understand those that say that they can't add networking. I can also tell you that it is not true. At every place I have rented the owners are more than willing to allow you to add networking to the home. This is assuming that it is done in a proper manner to codes and standards.

Now to the "foil backed drywall" argument. There are plenty of WiFi adapters out there that put out 200-400mW of energy. Add in a 10dB dipole antenna and you will be able to see your AP from across the city. Again, there is no reason for these devices except that you are lazy. The cost is even out of proportion to the performance they deliver.

Mike

By mikeiver on 14 Aug 2009

Clarification

There have been many mentions of Homeplug throughout this discussion.

There are two PLT Alliances, namely the HPA (Homeplug Alliance) and the UPA (Universal Powerline Alliance). They are totally different and are both marketed in the UK.

HPA will poll each other when dormant, which can be heard as regular burst of noise.

UPA are on-air 24/7 splattering noise across the spectrum regardless of whether they have data to transfer or not.

I would say that in the UK, 99%+ of complaints have been lodged against Comtrend products, which are UPA and are the PLT products that are being marketed y BT. These things are very noisy and make Homeplug look almost radio-friendly.

I have personally had Comtrend devices tested to EMC specifications that they claim to comply with at a UKAS accredited lab (ie they have the conditions to conduct official testing for type-approval). They fail by a factor of about 1000 (30dB). Paul, if you are interested, I would be very happy to share them with you.

Anyone interested would get a lot of information from www.ukqrm.org which includes sound recordings of the noise that the products produce.

73

By Richard101 on 14 Aug 2009

Thanks Richard

The article WAS about HomePlug, as that's what I'd recommended. I'm aware of the Comtrend devices - not only are they always active, they also don't have the notches covering the amateur bands. I'd certainly never recommend those (or BT Vision, for the same reason).

But despite me writing about *HomePlug* kit in the article, and reiterating the point in some of my follow-up comments here, many people (especially our American friends) keep banging on about other powerline data technologies.

It's a bit frustrating when people start spouting their well rehearsed arguments without properly reading the article first.

Perhaps your clarification will help.

Thanks again,

P.

By PaulOckenden on 14 Aug 2009

Clarification

There have been many mentions of Homeplug throughout this discussion.

There are two PLT Alliances, namely the HPA (Homeplug Alliance) and the UPA (Universal Powerline Alliance). They are totally different and are both marketed in the UK.

HPA will poll each other when dormant, which can be heard as regular burst of noise.

UPA are on-air 24/7 splattering noise across the spectrum regardless of whether they have data to transfer or not.

I would say that in the UK, 99%+ of complaints have been lodged against Comtrend products, which are UPA and are the PLT products that are being marketed y BT. These things are very noisy and make Homeplug look almost radio-friendly.

I have personally had Comtrend devices tested to EMC specifications that they claim to comply with at a UKAS accredited lab (ie they have the conditions to conduct official testing for type-approval). They fail by a factor of about 1000 (30dB). Paul, if you are interested, I would be very happy to share them with you.

Anyone interested would get a lot of information from www.ukqrm.org which includes sound recordings of the noise that the products produce.

73

By Richard101 on 14 Aug 2009

Comtrends, and notches

I have a pair of Comtrends - and they do have the amateur bands 'notched'. The noise is still there at the edges of each band, and there is no notch for the 5MHz band either.

BT are giving out adaptors with the CB band notched now as well.

We have to remember, that regardless of notches in these devices, the fact is that the pollute the radio spectrum - if radio amateurs accept them because they're notched, it's breeding the "I'm alright Jack" culture. There's more people affected than just Hams.

As for UPA vs. HPA, sure - the HPA devices are 'quieter' when not transferring data, but when transferring data they're just as bad.

I don't try to put my signal on 430MHz up bell wire to get to the aerial - and that's pretty much exactly what all of these things are doing. Interference is inevitable with this technology.

By Ayrshore on 14 Aug 2009

vs HF is obsolete

"By THE ASSOCIATED PRESS
Published: August 1, 2009

OWENSBORO, Ky. (AP) — Local officials are turning to older technology to solve some of the communication problems they encountered during January’s ice storm and the windstorm after Hurricane Ike in 2008...

“We lost communications for at least a day and a half,” said Walter Atherton, deputy director of the Daviess County Emergency Management Agency.

Amateur radio operators, on the other hand, were able to communicate throughout the ice storm...

Having amateur radio operators throughout the county would give real-time, on-the-scene feedback to emergency managers and to officials with the National Weather Service office in Paducah, Mr. Atherton said.

“There are so many circumstances where they could be our only contact with the outside world,” he said.
...

http://www.nytimes.com/2009/08/02/us/02kentucky.ht
ml?_r=1&scp=1&sq=kentucky%20ham%20radio&st=cse

By Markus on 17 Aug 2009

Those of you ham radio enthusiasts who keep using the emergency line should realize something. And that thing is; is that when a power lines failure and or the infrastructure has crumbled; there would be no Home powerline networks to supposedly interfere with ham radio signals.

The people who calling powerline network users lazy, why don't you ask your land lord is it okay to tear down the dry walls and rip down the wood panels to run ethernet cords through. If you were able to get then Okay, then look for an affordable contractor that will do the job for the price you could afford. It doesn't work that way for all of us just because YOU were able to add networking line or run cable through out your place.

2.4 ghz routers/modems do not work the way they used to. Especially if the walls are dry wall and the same for ceilings.

By Shavinex on 18 Jul 2010

@Paul

The example that a HAM legally pushing out 1.5KW is flawed - amateurs are licensed to a max of 400W.

Are you advocating that it is Ok to break the law? It is a fact that these devices break EM regulations. Unequivocal. Simply stating that they should be tolerated because they are convenient, in widespread use, and 'there is no other way' simply doesn't hold up; if those are your beliefs, do you apply them to the downloading of copyright material from usenet/P2P etc?

No, i didnt think so either. We might think the law is wrong, but it is fallacious to state so when the law is simply inconvenient, rather than morally wrong, as is the case here.

And why does this old topic keep appearing on the front page?

By alan_lj on 24 Feb 2011

@shavinex

eh? How do they not work in the way they used to? Have manufacturers managed to change the fundamental laws of physics?

By alan_lj on 24 Feb 2011

In two years, I've had 4 instances of interference to both DAB and short wave radio from neighbours' power line networking adapters. Ofcom resolved one, are still working on another, and my neighbours have got a refund on the things after I've had a word with them and showed them the effects.

It's not just enthusiasts affected, as the industry would like you to believe. Trying to pigeonhole the affected group won't make the problem disappear.

Further, the reason Ofcom's almost 300 complaints seem to come mostly from Radio enthusiasts is because they're the very group who know what the problem is and what to do about it. Joe public with his DAB reception kyboshed won't have that advantage, and neither will the myriad other spectrum users who find their radios emitting a horrible screech.

By Siver_Surfer on 18 May 2011

Radio smog

I have held an amateur radio licence since 1964. However, I now find it almost impossible to contiue with the hobby. Although living in a rural area, which one would expect to be reasonably interference free, I now suffer from the most terrible radio frequency noise.
There are carriers every 45 and 12 kHz from 1.8mHz to 30mHz running 24/7. These generate wide band noise between them.
If I caused this type of interference using my radio equipment my license would be revoked in very short order.
How is it that the manufactuers of home plug devices, and the like, can be allowed to produce devices which generate this awfull electronic smog. Backhander springs to mind.

By rongee on 29 Jun 2011

Ham smog

Well who cares, you radio users have been interfering with my TV signal for years, and you dont give a 2 hootes, I use home plugs for my internet and they are great, so im getting my own back after all those years of lines on my TV from ham radio great!
Dont trust WIFI poor reception and as for cable...those little clips snap off grrrrr, home plug all the way:}

By boggsy on 18 Aug 2011

@Boggsy

Because they contravene UK and international emission standards.

IF you were experiencing TV interference, why did you not report it to OFCOM? IF you were so sure it was a radio HAM, why did you not approach him, and resolve the issue (and report him to OFCOM if it continued)?

Is it ok to break the law in your book?

By alan_lj on 15 Sep 2011

Homeplug devastating interference

So, shortwave radio is a "legacy" hobby?
During 9/11, the buildings callapsing caused the emergency services to go "dark" because all their aerials were on the roof.
The internet virtually shut down due because the underground cables were severed!
The ONLY communications available to emergency services were Amateur Radio enthusiasts. They sprung into action and got services coordinated.
Radio frequencies are a finite valuable resourse and the authorities should get their fingers out and start behaving responsibly and stop these PLT devices once and for all.
I HAVE been the "victim" of PLT frequency abuse... yes, it IS abuse, no other term for it. Luckily my neighbour was very understanding.
These devices do NOT meet EMC standards and should NOT have the CE logo on them.
Anyone who doubts the validity of my message should research it.
I am VERY angry at the authorities who have allowed to get this far.
Soon enough, when the bandwidth required for the new HighSpeed devices is wider than at present, all you FM and DAB radios will start packing up!
Tip of a HUGE iceberg this is!

By MLHi_Fi on 27 Jul 2014

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Paul Ockenden

Paul Ockenden

Paul is a contributing editor to PC Pro specialising in smartphones, mobile broadband and all things wireless. He's technical director of a combined IT and marketing company, which works on websites and intranets for several blue-chip clients.

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