Broadband PLC low temperature limit

Why is the lower temperature operating limit on broadband PLC set at 0C ?
If you want to use it in an open garage that could present a problem.
I am contemplating use of BPLC in machine-to-machine networks and this limit
is frustrating. I have tested units rated to 0C down to -10C, but I'm not sure whether
the fact they kept working is just a fluke.
Maxmike

I think you're asking about programmable logic controllers. Unfortunately this site is about high-speed internet.

I should have said broadband power line communications. Sorry for lazy typing.

At a guess, you're using consumer (commercial) specification kit, this is intended to be used in environments where you'd also be comfortable.

If you want a wider range of operating temperature you'll need to find industrial (or even military) spec devices.

Operating temperature ranges

In reply to a post by Anonymous:

I should have said broadband power line communications. Sorry for lazy typing.

Oh, you mean BPL? I think you really mean Homeplugs?

In reply to a post by BatBoy:

In reply to a post by Anonymous:

I should have said broadband power line communications. Sorry for lazy typing.

Oh, you mean BPL? I think you really mean Homeplugs?

No, he means PlC, in the Amateur Radio world, we know it as interference, as few units come anywhere near complying with EMC requirements. SHOULD BE BANNED!
Not just homeplugs - PLT coming to a street near you. http://www.emcuk.co.uk/awareness/Pages/InterferenceE...
https://en.wikipedia.org/wiki/Power_line_communication
http://www.rsgb.org/emc/docs/pdf/archive/emcplc.pdf
http://ebookbrowse.com/rsgb-and-plt-interference-upd...

Edited by professor973 (Wed 22-Aug-12 22:44:52)

Actually, there is NO ham interference - they would be used in electrical lines that are inside metal conduits.

In reply to a post by Anonymous:

Actually, there is NO ham interference - they would be used in electrical lines that are inside metal conduits.

Actually, I have not seen any household wiring within metal conduits, or street three phase cables. Look around and check out the tests.
I don't know how you can train RF to travel along a unshielded cable without radiating as an antenna. If you crack that one let me know.
I actually said hams consider it interference. Despite homeplugs being notched at amateur frequencies, emissions are still above EEC EMC specs. More importantly, there are many other users of the spectrum that don't have the benefit of notch filtering.

Can you just put them in an insulated box?

We are deviating from my question, but in North America shielded (and grounded) conduit, particularly in large buildings is quite common. Even in houses we use BX cable which does the same.

Well, if they're insulated they won't reach the lower limit as they generate heat.

I was just about to say the same thing; when I had homeplugs / powerline devices / whatever you wish to call them, they were always quite warm. So I'd suspect that in a cold garage they'd still be fine.

..besides, my mobile is only rated down to 0c, but this winter just gone I left it in the car overnight; -15c that night and it worked fine. Using something outside its rated comfort zone, while not great, won't cause the device to skim off the face of the planet and vanish.

"many other users of the spectrum ... don't have the benefit of notch filtering. "

Such as, er, DSL. Whether it be ADSL, VDSL, or whatever, it's medium wave and short wave radio, except that the signals come down the phone wires rather than through the ether.

Anything that can and does interfere with medium wave and short wave radio can and at times will interfere with DSL broadband.

It's hard enough getting and keeping high speed DSL working as things are today without the prospect of having the RF spectrum increasingly polluted by powerline broadband kit too.

Trying to diagnose a DSL fault in the presence of interference from a powerline broadband transmitter somewhere between end customer and exchange/DSLAM/etc won't be fun.

In fact before too long if enough BPL/PLT kit gets out there, it's probably going to render xDSL undiagnosable in the case of a fault, and hence commercially unusable in the mass market.

This will be not just because of powerline ethernet kit, but because every consumer electronics manufacturer who sees BPL/PLT kit being allowed to radiate like crazy with no penalty will want to save a dollar or two per unit by no longer including the RF suppression components which have previously been considered essential.

But that's OK, because PLT helps sell BT Vision and the like, and we'll all have interference-free fibre to the premises in five years or so won't we. And in areas with a high density of PLT, we'll need something other than DSL. Shame about the non-FTTP areas where cable broadband isn't available either, but hey, it's a basic human right to pollute the RF spectrum so you can watch movies/football without paying Sky, innit.

I have not seen a homeplug yet that enables you to watch Sky TV for free. In fact they are far less efficient than running an Ethernet cable. They slow what is trundling down the copper already.
What is far more worrying, is the high power ISP PLT trials along street three phase mains cables, high up and unshielded and radiating left right and centre. You then get into recorded interference to aircraft communications, which still run HF on long haul flights. Homeplugs are a far more local problem as far as interference, though you could have a neighbour hook into your broadband if he is on the same phase.

Well over a million HomePlug devices in use in the UK so should have wiped out the amatuer radio, crashed a few planes and reduced ADSL to zero throughput by now

In reply to a post by MrSaffron:

Well over a million HomePlug devices in use in the UK so should have wiped out the amatuer radio, crashed a few planes and reduced ADSL to zero throughput by now

A check through the thread will show that homeplugs are notched at amateur frequencies, along with the recorded interference to the likes of aircraft relating to high powered ISP trials along street three phase � I realise getting the last word is paramount here, but it is best to wake up first!

How many airplanes have crashed in the UK as a result of these million HomePlug devices?

As for BPL for public ISP stuff, not aware of any live deployments, there was trials, but died a death not because of interference but costs and fixed lines exceeding by many times the speed capabilities

These devices, despite operating at HF, are quite happy to wipe out your neighbours Band 2 FM and DAB at VHF!. These are protected frequencies and you are liable legally for any interference caused.
https://www.youtube.com/watch?v=_wvtBhilvz4
An example of even the notched amateur frequencies being well out of spec.
https://www.youtube.com/watch?v=6teyGvdrs5Y&feature=...
Just imagine if PLT is ever let loose at high power street level by some 'Honest' ISP!

I take it the answer is zero.

In reply to a post by BatBoy:

I take it the answer is zero.

We are not discussing your IQ, which must be into minus if you resort to personal insults when faced with facts!

In reply to a post by professor973:

In reply to a post by BatBoy:

I take it the answer is zero.

We are not discussing your IQ, which must be into minus if you resort to personal insults when faced with facts!

What?

The answer to the question "how many planes crashed as a result of millions of HomePlug devices?" appears to be "zero".

You have resorted to your name calling again,

Debates are fine, but if one does not know answer it is acceptable to say so, rather than question someones IQ

PLC plugged in and operating, and DAB radio on and it still works.
So perhaps not all the devices are created equally, not disputing what the YouTube video showed, but perhaps issue is not a simple black and white one.

PLC/PLC is not going to appear on UK streets, that side is a dead duck for other commercial reasons

In reply to a post by professor973:

In reply to a post by BatBoy:

I take it the answer is zero.

We are not discussing your IQ, which must be into minus if you resort to personal insults when faced with facts!

Surely yours is the only personal insult in this thread? I fail completely to see one by BatBoy. Forgive me if I have missed it, and point me to it.

The answer to the question "how many planes crashed as a result of millions of HomePlug devices?" appears to be "zero".

Which exactly matches your reply to evidence of QRN.

In reply to a post by professor973:

The answer to the question "how many planes crashed as a result of millions of HomePlug devices?" appears to be "zero".

Which exactly matches your reply to evidence of QRN.

QRN Are the atmospherics strong? Atmospherics are very strong.

In reply to a post by MrSaffron:

PLC plugged in and operating, and DAB radio on and it still works.
So perhaps not all the devices are created equally, not disputing what the YouTube video showed, but perhaps issue is not a simple black and white one.

PLC/PLC is not going to appear on UK streets, that side is a dead duck for other commercial reasons

I think that like the VCR, you know very well that all devices are not created equally.
http://www.guardian.co.uk/technology/gamesblog/2008/...
Listen to them here. https://www.youtube.com/watch?v=MAzUtN29h1A

Edited by professor973 (Thu 23-Aug-12 12:17:21)

In reply to a post by professor973:

In reply to a post by MrSaffron:

PLC plugged in and operating, and DAB radio on and it still works.
So perhaps not all the devices are created equally, not disputing what the YouTube video showed, but perhaps issue is not a simple black and white one.

PLC/PLC is not going to appear on UK streets, that side is a dead duck for other commercial reasons

I think that like the VCR, you know very well that all devices are not created equally.
http://www.guardian.co.uk/technology/gamesblog/2008/...

On the bright side, no planes have crashed.

In reply to a post by BatBoy:

In reply to a post by professor973:

In reply to a post by MrSaffron:

PLC plugged in and operating, and DAB radio on and it still works.
So perhaps not all the devices are created equally, not disputing what the YouTube video showed, but perhaps issue is not a simple black and white one.

PLC/PLC is not going to appear on UK streets, that side is a dead duck for other commercial reasons

I think that like the VCR, you know very well that all devices are not created equally.
http://www.guardian.co.uk/technology/gamesblog/2008/...

On the bright side, no planes have crashed.

Many have crashed with some suspected the result of interference. Possibly you don't remember the airliner that just made it over the fence before belly flopping onto the grass. Communications from Gordon Browns passing limmo were the prime suspect.
http://www.dailymail.co.uk/news/article-509004/Crash...

I don't think he was using HomePlugs in his car. The clue is in the name.

Edited by deleted (Thu 23-Aug-12 12:38:51)

In reply to a post by BatBoy:

In reply to a post by professor973:

In reply to a post by BatBoy:

... nested quotes trimmed ...

On the bright side, no planes have crashed.

Many have crashed with some suspected the result of interference. Possibly you don't remember the airliner that just made it over the fence before belly flopping onto the grass. Communications from Gordon Browns passing limmo were the prime suspect.
http://www.dailymail.co.uk/news/article-509004/Crash...

I don't think he was using HomePlugs in his car. The clue is in the name.

Think is not good enough, you need to be 100% sure before making a statement.

I am, but I didn't want to upset you by appearing cocky.

Think is not good enough, you need to be 100% sure before making a statement.

There is no logic in your statement. BatBoy stated that he thought something. I am sure he was sure in stating what he was thinking. The possibility that what he was thinking was incorrect isn't the issue.

My stating that is of course legitimately questionable, as I have no more objective means than you of knowing whether or not he was sure what he was thinking. I merely have a belief based on several years' observation that he is consistently rational in his thinking and statements. An excellent quality .

If you want to be taken seriously then bother to read the crash investigation rather than some sensationalist newspaper article.

Fuel line blockages due to ice.
http://www.aaib.gov.uk/publications/formal_reports/1...

RF from the passing limo - even if it were the case, what has that to do with HomePlug devices?

In reply to a post by RobertoS:

I merely have a belief based on several years' observation that he is consistently rational in his thinking and statements. An excellent quality .

You and Batboy friends?

It won't last!

Best friends. You want to be in the gang too?
You can join now you've removed that awful yellow from your sig.

In reply to a post by BatBoy:

I am, but I didn't want to upset you by appearing cocky.

Far too late for that old man � Enough playing with the pond for today, wonga to generate.

In reply to a post by MrSaffron:

If you want to be taken seriously then bother to read the crash investigation rather than some sensationalist newspaper article.

Fuel line blockages due to ice.
http://www.aaib.gov.uk/publications/formal_reports/1...

RF from the passing limo - even if it were the case, what has that to do with HomePlug devices?

I am well aware of the outcome of the crash investigation. I stated it was a suspected cause,. simply pointing out that these things do exist and are taken seriously

In reply to a post by professor973:

In reply to a post by BatBoy:

I am, but I didn't want to upset you by appearing cocky.

Far too late for that old man � Enough playing with the pond for today, wonga to generate.

I should thank Prince Harry for that quote.

Thanks!

The highlight was a bit naff wasn't it. Sorry

Shame that the signature doesnt change for posts made before the change

In reply to a post by greenglide:

You and Batboy friends?

It won't last!

Indeed we are - and (I think [cough]) it will last. It is perfectly possible to be friends with someone and disagree strongly with them occasionally.

Though he and I seem to disagree less and less often. Maybe one or both of us should be worried about that .

"Well over a million HomePlug devices in use in the UK so should have wiped out the amatuer radio, crashed a few planes and reduced ADSL to zero throughput by now "

[You call it Homeplug, I'll call it PLT, we mean the same thing]

Amateur radio clearly has been affected; there is plenty of evidence (although sometimes there is also more heat than light being shed on the subject).

ADSL throughput: where would what you call "evidence" come from, how much would it cost to get it, and who should be doing those investigations?

Whatever the area, the evidence is likely to come from long and tedious investigations. Other products sometimes interfere with DSL, but when properly designed properly certified products interfere with DSL it's generally down to faulty components which can be fixed. When these faulty products (Sky boxes, whatever) are identified as the source of a DSL problem it is typically after a long, tedious, expensive investigation requiring specialist skills (skills which just happen to be the same kind of skills some radio amateurs might have). Anyway once the problem is eventually identified the fix is usually easy - replace the offending item with a non-faulty one, and everyone is happy.

PLT kit doesn't just interfere when components go faulty. PLT kit interferes as a direct consequence of its intended design and use.

Anyone who's followed AG/TB for a significant time knows that getting unusual DSL faults fixed or investigated can be painfully tedious at the best of times. Who really thinks those expensive investigations are going to happen when a "quick fix" such as a pair swap will in many cases fix the symptom (in the short term) without too much effort or cost to the DSL supplier? Who cares if the pair swap doesn't really fix the underlying problem, just hides it till next time someone's DSL is affected?

Oh, and the field technicians who would be doing any UK investigation work for the same plc which is the biggest UK seller of the interfering product. That investigation's not gonna happen, is it, because it's inconvenient and expensive. So there's not going to be any "evidence" from that source is there. And there are DSL experts in the standards/R+D part of that same plc who know the full story too, but they too have bills and mortgages to pay, and they know exactly what would happen if they told their side of the story.

Yet there is plenty of proof that the interference from PLT can exist, and does exist, and that the interference is a necessary consequence of the basic product design especially in combination with UK wiring practices.

There is good reason based on the fundamentals of physics and RF propagation to believe that the interference will get worse everywhere that more PLT kit is deployed and as PLT speeds increase. Yes the interference may not occur in 100% of installations for 100% of the time, just as MW and SW reception varies by location and time. No surprise there.

Absence of evidence is not evidence of absence.

PLT is defective by design.

+1

In reply to a post by Anonymous:

"Well over a million HomePlug devices in use in the UK so should have wiped out the amatuer radio, crashed a few planes and reduced ADSL to zero throughput by now "

Absence of evidence is not evidence of absence.

So when can we expect a plane crash disaster due to HomePlugs?

Isn't amateur radio interfering with (non-Homeplug) DSL usage much more of an issue to the general public?

If a licenced radio amateur is found to be causing unwarranted interference with other uses of the radio spectrum, then there are procedures in place, procedures happily agreed by the amateurs, for addressing such interference. If the amateur's kit is misbehaving, it will be fixed (or removed from use). If the amateur is misbehaving, the licence can be revoked (or worse).

If the radio amateur's use is legitimate under the licence but is causing interference due to bad design of (or faults in) other equipment (e.g. consumer electronics which has insufficient rejection of out-of-band signals) then any decent amateur will generally work with the affected party to resolve things amicably, often involving a few pence worth of attenuators or RFI fiters on cabling. In the unlikely event that the particular amateur involved happens to be an awkward git (they exist everywhere), other more sensible amateurs will generally help out; it's in everyone's interests to do so.

Where's the problem with that?

You can't fix PLT kit with simple fixes like that. PLT kit is designed to send significant levels of wideband RF interference down mains cable. It is designed to receive RF from mains cable. If you stop PLT kit transmitting RF interference down mains cable, it no longer performs as advertised, and no one will buy it.

The fact that PLT vendors have had to agree to "notch" their unlicenced transmissions in order to keep out of the way of a small number of legitmate spectrum users is effectively an admission that their use of masses of the remaining "un notched" RF spectrum is neither authorised nor legitimate. And without unlicenced (ab)use of masses of RF spectrum, their products cannot work in any meaningful reliable way.

Ye canna change the laws of physics, cap'n.

Defective by design.

See also related recent discussion on
http://forums.theregister.co.uk/forum/1/2012/08/20/p...


Batboy: I'm not familiar with any recent aircraft-comms-related claims in this context. Are you?

I do have a vague recollection of a mention of that kind of thing in various of the Radio Authority's PLT Technical Working Group reports a decade or so ago, but I haven't re-read them lately and can't remember the details from back then. Do you remember them, or is there perhaps a current equivalent you're familiar with?

In reply to a post by Anonymous:

If a licenced radio amateur is found to be causing unwarranted interference with other uses of the radio spectrum, then there are procedures in place, procedures happily agreed by the amateurs, for addressing such interference. If the amateur's kit is misbehaving, it will be fixed (or removed from use). If the amateur is misbehaving, the licence can be revoked (or worse).

In reply to a post by Anonymous:

"... the evidence is likely to come from long and tedious investigations.

The person affected will be totally unaware of the effect of amateur radio, and probably equally unaware that his broadband is screwed by it. He just knows it isn't as good as what he reads about in the press or adverts.

The problem will not be reported, never mind "long and tedious investigations" requiring a specialist Openreach employee being requested, with a threat of a potential bill to the user of well over £100.

Your arguments make technical sense, but seem to come from an ivory tower.

Maybe if I do bin plots with router sat on top of a HomePlug when switch on and off we will see the clear a wiping out of swathes of the bins. If I recall I do see bins lost due to a couple of AM radio stations.

NOTE: Not saying I have never seen seen problems reported, remember a clear case of a wireless mouse not working when Comtrend units were used. The incidence level is around that of Plasma TV's causing issues, and tread mills.

"The person affected will be totally unaware of the effect of >>xyz<<, and probably equally unaware that his broadband is screwed by it. He just knows it isn't as good as what he reads about in the press or adverts.

The problem will not be reported, never mind "long and tedious investigations" requiring a specialist Openreach employee being requested, with a threat of a potential bill to the user of well over £100."

Exactly. I'm quite happy with that, whether xyz might be amateur radio, or might equally be PLT.

Licenced radio amateaurs have the use of a tiny tiny tiny part of the RF spectrum, therefore their effects (on DSL and other spectrum users) are necessarily limited. In reality there also aren't many of them around.

And well designed DSL kit together with well designed regulatorily approved amateur transmitters can happily coexist. If amateur transmissions do occasionally get in the way of a DSL connection, the DSL kit will hopefully just avoid the small number of bins which may be affected, leaving the rest to continue doing what they usually do. In the unlikely event that the amateur transmissions do have sufficient adverse effects that an investigation does occur, there are remedies that can be applied, and everybody can be happy.

The same does not apply to PLT.

For PLT to work as advertised it necessarily needs to use masses of RF spectrum. As PLT is more widely used and as it attempts to increase its speeds it will increasingly frequently interfere with the legitimate users of that RF spectrum. That's just basic physics, you can't avoid it.

As you rightly point out, it will be difficult for the man in the street (or even the SFI technician with the skills) to identify a particular PLT installation as the cause of any given misbehaviour.

But it has clearly been shown already that such misbehaviour can and will occur in the presence of unwanted RF signals. That's the reason that electronics kit has to meet certain regulatory approvals (the EMC regulations which the PLT people want changed so their kit can SHOUT LOUDER down the mains).

In the unlikely event that a PLT installation is identified as the cause of DSL problems there are probably no practical remedies (other than not using PLT).

Just say no, unless PLT can meet the same RF regulatory requirements as other electronics. And it can't. By design.

Can you clarify what you mean by DSL.

As the various standards have very different frequency bands, e.g. ADSL is just up to 1.1MHz, ADSL2+ up to 2.2 MHz. VDSL2 currently up to 17 MHz. In future VDSL2 may extend to 30 MHz

"Maybe if I do bin plots with router sat on top of a HomePlug when switch on and off we will see the clear a wiping out of swathes of the bins. If I recall I do see bins lost due to a couple of AM radio stations."

It's a start. Now repeat the same exercise with a representative sample of domestic and non-domestic wiring, not just your own. Then we're getting somewhere.

Or, do what the electronics professionals have been doing for years, go back to basics and understand that (as I just wrote to Roberto) the EMC regs are there for a purpose - to make sure that sensibly designed electronics kit can all coexist without having an EMC specialist assess every individual combination for compatibility before it's used in the real world.

The PLT people are struggling to work within the existing EMC regs, which is why they want the rules changed to allow PLT kit to SHOUT LOUDER. Then you'd probably lose a few more bins.

"The incidence level is around that of Plasma TV's causing issues, and tread mills."

What we know of those is the *reported* incidence level. The real level may or may not be higher.

If Homeplug usage increases and permissible transmission levels are increased, wil the numbers of problems increase? Yes, of course, just like 2.4GHz WiFi has become decreasingly useful as more 2.4GHz kit is deployed in a given area.

But will the number of DSL problems identified as due to PLT also increase? Different question altogether. If a pair swap or some other easy tactic fixes it without further investigation (and sometimes it will), no one will know it's a PLT problem.

Absence of evidence is not evidence of absence.

In reply to a post by Anonymous:

Absence of evidence is not evidence of absence.

Ah but it is. The hysterical squawking of Henny-Penny that the sky will fall in is just noise without evidence.

Where is your evidence of planes falling from the sky? There is none.
Where is your evidence of DSL being wiped out? There is none.

On the other hand, there are plenty of planes flying about and plenty of DSL users, which is evidence that what your are saying is mistaken.

"the various [DSL] standards have very different frequency bands, e.g. ADSL is just up to 1.1MHz, ADSL2+ up to 2.2 MHz. VDSL2 currently up to 17 MHz. In future VDSL2 may extend to 30 MHz "

Exactly. Higher speeds need to use more frequencies. Basic laws of physics. Same basic physics applies to both DSL (of whatever kind) and to PLT. They both want higher speeds, they both have to use wider frequency ranges to deliver it (if they can't improve the SNR).

The DSL people have the various DSL standards and things like the ANFP to ensure that various DSL standards and kit can coexist amongst themselves and with other electronics kit.

The PLT people have what? The figleaf of notching doesn't really cut it. Their attempt to improve the SNR is to try to change the regulatons so the can SHOUT LOUDER.

I need to be somewhere else. Enjoy the break

Even Henny Penny might have understood that if you've got two lots of folk attempting to use the same radio frequencies for different things, it may end in tears. She may not even have needed evidence, because she might have understood it from the days of AM radio when the sky went dark and you got two stations on the same frequency.

What we need is a regulator to allocate the frequencies appropriately. Perhaps OFCOM could sort it out?

In reply to a post by Anonymous:

Even Henny Penny might have understood that if you've got two lots of folk attempting to use the same radio frequencies for different things, it may end in tears. She may not even have needed evidence, because she might have understood it from the days of AM radio when the sky went dark and you got two stations on the same frequency.

He is confused enough already without getting into D layer!

There's nothing to be confused about. Without evidence, there's nothing.

So when can we expect a plane crash disaster due to HomePlugs?

About five minutes after some fool plugs one in at NATS Prestwick !

In reply to a post by professor973:

Any idea of the day, month and year?

In reply to a post by professor973:

So when can we expect a plane crash disaster due to HomePlugs?

About five minutes after some fool plugs one in at NATS Prestwick !


Do you have insider knowledge that someone hasn't already done so? They may be happily running homeplug for their network.

In reply to a post by BatBoy:

In reply to a post by professor973:

Any idea of the day, month and year?

Look!

In reply to a post by Anonymous:

Even Henny Penny might have understood that if you've got two lots of folk attempting to use the same radio frequencies for different things, it may end in tears. She may not even have needed evidence, because she might have understood it from the days of AM radio when the sky went dark and you got two stations on the same frequency.

My name isn't Henny Penny, (who is/was that?), but wasn't pleased about the poor reception on Radio Luxemburg at night.

In reply to a post by professor973:

In reply to a post by BatBoy:

In reply to a post by professor973:

Any idea of the day, month and year?

[http://2.bp.blogspot.com/_0LsEtlzNZXY/SpDjSLWTRbI/AAAAAAAAA6o/bkO8wpdI9JM/s400/no+eye+deer.jpg
look! [/q]

No thanks

http://www.authorama.com/english-fairy-tales-23.html

Perhaps Batboy isn't aware, but there already is a set of agreements to allocate frequencies appropriately. Given that much of the market is global, and some of the spectrum travels globally, there are global agreements on who gets what spectrum.

Licenced amateurs get some, FM radio gets some, broadcast TV gets some. You get the gist. Pretty much everything is allocated to someone somewhere.

Sometimes folk need a licence to operate a transmitter (eg in the broadcast bands). Sometimes you can buy and operate kit which is made under a generic licence (CB, 2.4GHz, etc) and the end user doesn't need a licence, typically because the kit is built to regulations which ensure that any effects it has are localised geographically and kept within the specific frequency ranges as specified under that licence.

PLT doesn't have any frequency allocation, even though these folks are transmitting on frequencies all the way from relatively low frequencies to tens and sometimes hundreds of MHz. Even if they were allocated a few MHz or tens of MHz (from where?) it would be no good to them as due to the nature of physics, the data rates they could achieve would be such that almost nobody would be interested in it. It certainly wouldn't be mass market technology.

Ofcom does have a role in this. Ofcom's role, as successor to the Radio Authority in these matters, is the enforcement of the existing regulations referring to unauthorised radio transmissions (accidental or otherwise).

Given what we know of Ofcom as a competent and effective regulator, should anybody be surprised that there's nothing that Batboy would class as "evidence"?

What *should* any reasonable member of the public class as evidence?

Perhaps some reasonable folk might consider it as "evidence" that the industry professionals and other competent bodies and individuals, other than those directly or indirectly dependent on the PLT industry, have generally said the existing emissions regulations should be properly enforced, which would see PLT off the market.

What doesn't count as meaningful evidence is interested bystanders saying "I tried it and it all worked OK for me". Even if well intended, that kind of thing is not evidence, that's anecdote.

Two sets of mains cables in a big open space, powered by two sets of indepdent generators, talking to each other via PLT without any wired connection between the two sets of cables might arguably be considered as evidence that PLT is an unauthorised radio transmitter. There have been several demonstrations of that happening.

So we can discount any youtube videos as they are also interested bystanders?

What PLT devices were used in this field test? And how far apart were the cables?

Looks like an admission of a further lack of evidence.
Is there *any* documented evidence for this hysteria at all?

Why would you discoount a youtube video because it's a youtube video?

You'd look at the parties involved, their backgrounds, the credibility of their evidence, the consistency of their argument, whether they had anything to bring to the table.

Then you might discount it, you might not. That's the way science works. Facts, analysis.

If they were just interested bystanders, you'd ask the questions you quite rightly asked, as I did at the time, which was a while ago.

I don't have the answers to those questions right now, nor do I have the time right now.

Feel free to go and dig it up.

Meanwhile, the EMC professionals and other interested parties who are independent of the PLT outfits, just want the existing EMC regulations enforced.

If the existing EMC regulations had been properly enforced, there would have been no instances of "Christmas tree lights broke my DSL".

That didn't happen with every set of lights, but mostly with broken by design ones.

PLT is broken by design, the EVIDENCE from the EMC professionals is that it can't meet the agreed existing regulations when realistically tested, because it relies on sending high levels of wideband RF down wiring never intended to handle RF, into an environment where various services depend on a relatively clean RF environment.

Widespread use of PLT is incompatible with the continued use of existing services which need a clean RF spectrum. DSL is one, another is amateur radio, there are others.

The PLT people gave the chosen few spectrum users their "notches". What about the rest?

Why don't amateur radio users embrace the internet for communications, like everyone else?

In reply to a post by BatBoy:

Why don't amateur radio users embrace the internet for communications, like everyone else?

Surely not another utterly stupid question � It's NOT RADIO!

In reply to a post by professor973:

In reply to a post by BatBoy:

Why don't amateur radio users embrace the internet for communications, like everyone else?

Surely not another utterly stupid question � It's NOT RADIO!

What is it then, if not amateur radio?

The Radio Society of Great Britain might disagree.

That's a big 10-4 good buddy.

You should have posted that yesterday.

In reply to a post by camieabz:

The Radio Society of Great Britain might disagree.

I can assure you as a member, that the RSGB do not consider Internet as Radio. In the event of a disaster, where all communications were wiped out, we are licensed to handle third party traffic such as all emergency services.

In reply to a post by BatBoy:

That's a big 10-4 good buddy.

That is the usual numbskull reply from an id that does not know the difference between Amateur Radio and C.B.

What qualities does radio have that internet doesn't?

In reply to a post by BatBoy:

In reply to a post by professor973:

In reply to a post by BatBoy:

Why don't amateur radio users embrace the internet for communications, like everyone else?

Surely not another utterly stupid question � It's NOT RADIO!

What is it then, if not amateur radio?

Batboy � Or Batty Boy??

I'm coming at you on a big fat Medium Wave, Bro.

Ah, an ad hominem attack - the last gasp of a lost argument.

In reply to a post by BatBoy:

What qualities does radio have that internet doesn't?

If you really don't know, then instead of calling the odds in this thread, you really should don your anorak and use your Internet to find out. I will therefore leave you to play with yourself.

In reply to a post by BatBoy:

I'm coming at you on a big fat Medium Wave, Bro.

So what mode is that Sis? Sounds obese compared to CW.

I thought you would know, good buddy.
As far I can see they are the same.

In reply to a post by professor973:

In reply to a post by BatBoy:

I'm coming at you on a big fat Medium Wave, Bro.

So what mode is that Sis? Sounds obese compared to CW.

DSL mode, Billy.

Remember debate the issue, not the attacks on individuals

In reply to a post by MrSaffron:

Remember debate the issue, not the attacks on individuals

Does that include nauseating idiots? I will give as good as I get. Ban me as and when you see fit, no need for further acidic inter-board memos!

In reply to a post by professor973:

In reply to a post by MrSaffron:

Remember debate the issue, not the attacks on individuals

Does that include nauseating idiots?

Yes, he means you. You can't even answer a simple question of how radio differs from the Internet.

The each have their own strengths and weaknesses when it comes to maintaining communications in the face of difficulties of various kinds. We would do well to make sure that both remain as viable alternatives.

In reply to a post by MrSaffron:

Remember debate the issue, not the attacks on individuals

We don't seem to be anywhere near the issue, which appears to have got lost long ago, and IIRC referred to usage in the USA. Maybe Canada.

Edited by RobertoS (Sat 25-Aug-12 13:47:45)

Absolutely, we can always revert to radio if ever the internet goes down. The next fallback would be morse code.

One advantage of amateur radio is that the knowledge level needed to use it sets the bar quite a bit higher which has the happy consequence of disbarring most of the idiots.

Which is one of the reasons it's been overtaken by the internet. But it's useful as a last resort if the the internet goes down.

Hi Professor,

I *used* to use Mains-Networking, but found it to be too unstable.
To mitigate my interference at the time (I was also using Marmitek X10 systems), I fitted a Marmitek FD10 Phase Coupler/Filter to try and control it.
Like I said, I don't use any of that stuff any more, but you can find out about the filter here -
http://www.marmitek.com/en/pdf/08934.pdf

TBH, I don't know if it ever made a difference, but it seemed like the decent thing to do.
There are other filters out there that hopefully will cut down on the muck that gets injected back into the mains!

Sadly, like light-pollution, airwaves-pollution is a bane of our times.

See you said:

In reply to a post by professor973:

Surely not another utterly stupid question � It's NOT RADIO!

Which I took you to mean that the amateur radio stuff 'is not radio'. Now I see that you mean the 'Internet is not radio'.

Fair enough. Each to their own.

In reply to a post by camieabz:

See you said:

In reply to a post by professor973:

Surely not another utterly stupid question � It's NOT RADIO!

Which I took you to mean that the amateur radio stuff 'is not radio'. Now I see that you mean the 'Internet is not radio'.

Fair enough. Each to their own.

OK no problem. being involved with both, I would like to think I could show my RAE students the difference between computer data and RF. Just think if our ADSL could break through the D layer. You could then work the skip worldwide without being ripped off via an ISP. A three minute Radio call costs exactly @8#* all!

In reply to a post by gomezz:

One advantage of amateur radio is that the knowledge level needed to use it sets the bar quite a bit higher which has the happy consequence of disbarring most of the idiots.

There is a lot of knowledge out there. Many things we take for granted today were proven by Amateur radio enthusiasts. There was a time when microwave communications were considered good for no further than between two lampposts.
Try this with the web or CB. http://ham.portraitme.info/e107_plugins/forum/forum_...
Others are into infra-red and other forms of light comms. You are licensed to build and experiment with virtually what you like, unlike the Internet.

Edited by professor973 (Sat 25-Aug-12 18:27:07)

In reply to a post by BatBoy:

DSL mode, Billy.

Radio KAOS?

Edited by Deadbeat (Mon 27-Aug-12 14:52:37)

That article about sending signals further by using the metal aircraft body to bounce them off is rather cool!

It's always a tough debate, regarding the use of home powerline adaptors in place of ethernet or wifi. I used a set of Comtrend ones for a period of around 2 years when living in central Manchester. The 2.4Ghz band was terrible - about 30 networks there, not to mention 2.4Ghz video senders and stuff. As the property was rented & had hardwood floors, I could really dust the drill off to run cat5 nor tuck it under the nonexistent carpet. So, powerline adaptors it was.

Now I'm in a property I own, I've since run Cat5e everywhere, so could sell them on. They were, frustratingly for radio amateurs, reliable and effective. But, of course, offensive. And in my case, slower than gigabit cat5e, so they went!