Ahern looks to power grid for broadband

dahamsta

Ahern looks to power grid for broadband
Monday, August 18 2003
by Matthew Clark

The Minister for Communications Dermot Ahern on Monday confirmed that the government is supporting a trial of broadband over electricity wires.

The Minister said that the trials are set to take place, mainly in the Tuam, Co. Galway area, in conjunction with the ESB. This scheme is part of the EUR50 million project been co-funded by the Department of Communications under the National Development Plan 2000-2006 to broadband-enable ESB's transmission network nationally.

The department said the ESB is also funding the trial, with early tests set to commence in the next few months that will see homes, schools and businesses hooked up to high-speed Internet connections, with the Internet traffic travelling over ESB power lines.

"Powerline communications (PLC) systems have the potential to provide an alternative broadband infrastructure, which can compete with local fixed telephony, cable, and wireless networks," the Minister said in a statement, claiming that the development of the little-used technology has reached a phase where it could be a feasible alternative to traditional broadband networks.

[...]

My stirring spoon is enormous.

Eurorunner

From the info thats filtering thru on the boards, it looks like the only thing PLTs going to be used for is 'political gain'.

a PR exercise for the masses...:rolleyes:

bminish

I note that that the ENN article mentions the rural broadband issue.

Indeed, PLC has been looked upon for years as a solution to the emerging digital divide that has seen rural areas neglected when it comes to high-speed Internet infrastructure rollout.

Interesting, considering this is in relation to yet another urban trial of PLT. Not one single trial anywhere in the world has shown PLT to be capable of delivering broadband over a distance greater than around 2,000 feet without need for costly and hard to fit repeaters.

there is a mention of the repeater system for PLT here
http://whirlpool.net.au/article.cfm?id=1075&show=all
A repeater every 200 to 250m, that's a lot of costly live line work.
Interesting how there is no mention of this on mainnet's own web site
http://www.mainnet-plc.com/



PLT (also called PLC or BPL) systems recently closed down following trials include

Finland (due to poor performance & EMC issues to radio users )
http://www.darc.de/referate/emv/plc/plc-oh.pdf

Netherlands (not cost effective, Interference issues )
http://www.webwereld.nl/nieuws/14920.phtml
Translation here
http://www.arrl.org/tis/info/HTML/plc/#Amateur_Interference_Studies
Scroll down to PLC in other countries.


Japan bans PLT systems (interference to radio users)
http://www.jarl.or.jp/English/4_Library/A-4-1_News/jn0208.htm

Italy
All trials ceased, no further trials planned
http://www.darc.de/referate/emv/plc/plt-symposium.pdf

Hungary
It is not anticipated that Power Line Technology will be introduced into West European Countries for some time.
http://www.darc.de/referate/emv/plc/plt-symposium.pdf

Poland
No further trials are being held in Poland
http://www.darc.de/referate/emv/plc/plt-symposium.pdf

In Germany the trials not going well, Siemens stop manufacturing PLT equipment, poor real world performance of the mainnet system. See updates at
http://www.darc.de/referate/emv/plc/


PLT a risky undertaking
http://www.darc.de/referate/emv/plc/PLT-Market-version.pdf


PLC fails to meet EU EMC directives
http://www.ce-mag.com/archive/02/09/edpage.html
http://www.ieee.org/organizations/pubs/newsletters/emcs/winter01/hansen.htm

Some more links
My previous comments on this issue
http://boards.ie/vbulletin/showthread.php?postid=1026827#post1026827
Some boards debate on this
http://www.boards.ie/vbulletin/showthread.php?s=&threadid=110048

Links concerning the serious problems PLT (also called PLC or BPL) causes to radio users. Sound clips and video examples available from some of these links

ARRL (US)
http://www.arrl.org/tis/info/HTML/plc/

A very comprehensive collection of links, Incudes links to manufactures web sites etc
look closely for any evedence of successful rural trials on the manufacturers web sites.

RSGB (UK)
http://www.rsgb.org/emc/pltnew.htm

DARC (Germany) in German & English
http://www.darc.de/referate/emv/plc/

Hey Adam, You just knew I was going to reply to this didn't you

Brendan

dahamsta

Course I did Brendan, why do you think I posted it?

As regards the starter for ten, the very next paragraph in the article does address your point:

the rollout of power line communications still requires users to be within a few miles of an electricity sub-station, not unlike the way ADSL users must be relatively close to phone exchanges.

Picking and choosing sentences isn't playing fair.

adam

bminish

Even claiming a few miles is marketing spin from the PLT people. Where have they actually done this in trials?

The Tuam trials will not cover a 'few miles' it covers the center of the Town and 1 industrial estate. There is nothing even remotely rural about the forthcoming Tuam trials.

If PLT is injected at the substation as in your reference, line work then needs to be done to bridge between the 10Kv lines and the 240 volt line at each transformer and it still only reaches a max of around 2,000 feet without needing repeaters every 700 feet or so.
I can find no details of the repeaters but here are some of the technical issues that will need to be addressed by the design of the repeaters

Power for the repeaters must be provided from a 10Kv line without compromising line safety. Not easy

Repeaters need to be able to survive huge power surges, massive spikes induced by lightning etc.

The input of the repeater will need to be isolated from the output unless the throughput is halved at every repeater. you can't just cut 10Kv lines every 700 feet and stick a box in line.

The bridge across the transformers between the 10 Kv line and the 240 v line will not be cheap as a very high performance is required here, breakdown of this bridge under any circumstances would have serious consequences for the ESB consumer..

Even if you can have all this for free it's still not going to be cost effective to have live line rated ESB technicians install repeaters every 700 feet on the rural network and bridges at every transformer.

PLT isn't a rural solution no matter how the PLT lobby try to spin things.


Brendan

bk

This story has gotten a mention on TheReg "Ireland to trial broadband over power cables" including a mention of IrelandOffLine.

Dangger

Yup, Tim Richardson rang me seconds after I had finished reading sections of Brendan's links, as had Christian when he spoke to him. Hence the aprehension!

SkepticOne

Here's a link to the Southern Electricity broadband site:

http://www.southern-electric.co.uk/broadband/index.asp

Interference issues aside for a moment, this is the sort of thing we could have done with in Ireland years ago to give Eircom a bit of competition.

bminish

Here's a link to the Southern Electricity broadband site:

http://www.southern-electric.co.uk/broadband/index.asp

Interference issues aside for a moment, this is the sort of thing we could have done with in Ireland years ago to give Eircom a bit of competition.

Whilst I am all for giving Eircom a bit of competition to chew on, PLT is not the way to do it.

It is interesting how none of the UK PLT operators actually give information on the areas where PLT is available to customers, one suspects that the coverage areas are very limited.

Brendan

dahamsta

'Nother discussion on Slashdot. The classic battle between "embracing the future" and "if it ain't broke"...

During Blackout, Ham Radio Shined
Posted by timothy on Tuesday August 19, @11:52PM
from the breaker-breaker dept.
Mark Cantrell writes "An interesting bit on AP through Yahoo today. Seems that ham radio (which recently had a bit of backlash here on Slashdot from a few people thinking it was useless, outdated, technology), really shined through during the blackouts. When the power went, ham radio operators, using battery backup power, were able to help coordinate emergency workers while the cell phone networks were overloaded. For anyone wondering why interference due to power line broadband is considered a bad thing, well, there ya go."

Cuauhtemoc

True.
But in that instance Plt would have had no effect on Ham's anyway.

From what i've seen/read the people at the esb are fairly clued in and would be aware of the various positives/negatives of plt trials around the world.
Surely they wouldn't embark on a non starter, or are they being pushed by the government?

____
C.

bminish

True.
But in that instance Plt would have had no effect on Ham's anyway.

Unfortunately that isn't true, deployment of PLT systems affects the ability to receive. Presumably much communication was between areas affected by power cuts and areas not affected by power cuts...

HF radio is one of the things that makes Amateur radio so useful in emergency situations as it allows communication over long distances at low power levels without any other supporting infrastructure such as repeater stations.

In the States amateur radio is regularly called upon for emergency support.
here are some links to articles on this
http://www.arrl.org/pio/emergen3.html
http://www.arrl.org/pio/press_releases/pr021119.html
http://www.amityvillerecord.com/news/2002/0731/Front_Page/013.html
http://www.nyc-races.org/

In Ireland we are part of the various County Emergency plans, thankfully Ireland hasn't much of a history of big emergency situations. Many of us in Ireland are prepared to help if we are ever needed.

From what i've seen/read the people at the esb are fairly clued in and would be aware of the various positives/negatives of plt trials around the world.
Surely they wouldn't embark on a non starter, or are they being pushed by the government?

Whilst I am sure the ESB are fairly clued in and in my experience are a pretty competent bunch, the PLT companies work really hard to play down the problems with their technology and have tightly controlled all information concerning trials, you won't see much detailed information from the PLT people or the power companies involved concerning the many trials that have not gone well and are finished. I smell non-Disclosure agreements.

The EMC (electro magnetic compatibility (i.e radio interference issue) is a big one on many many levels with PLT but if you visit the PLT companies you would not even be aware that there was an issue with EMC

Here is a link to a detailed report done by the European Radio Office on PLT vDSL etc
http://www.ero.dk/
Interestingly vDSL has relatively few problems meeting tight EMC limits although the potential problems are also covered in this report.
http://www.ero.dk/documentation/docs/docfiles.asp?docid=1941


I am pretty sure it's a Government ' push ' after all the Government are paying for it (with my tax money too..)

The government seems quite happy to embark on the occasional non-starter and often seems completely unaware of what work is being done by other EU countries and the various EU standards and regulatory bodies.

Brendan.

sceptre

Originally posted by bminish
Unfortunately that isn't true, deployment of PLT systems affects the ability to receive. Presumably much communication was between areas affected by power cuts and areas not affected by power cuts...

In any case I suspect no ham operator would kep equipment lying around on the off-chance there might be a power cut and hence a chance to use it:)

dahamsta

Power cable broadband trial goes live today
By Tim Richardson
Posted: 20/08/2003 at 15:08 GMT

The future of broadband in rural areas via electrical cables hinges on the success of a commercial trial that got underway in Winchester today.

Powerline Communication (PLC) technology, which uses the existing electricity network to deliver broadband by simply plugging a specially-adapted modem into a socket, has already been trialed in Scotland.

Now, though, PLC is facing a commercial trial to see whether it can compete in the market alongside other broadband technologies such as ADSL and cable.

[...]

Let's put the interference issue aside for a minute and deal with the cost issue. Answer me this: If PLC isn't going to be cost-effective, why is the guy in this article so bullish on it? He's an employee of the power company and it's quite possible that his career rests on pulling this off. Barring massive shareholdings in a manufacturer, why would he take such a huge risk?

adam

bminish

Let's put the interference issue aside for a minute and deal with the cost issue. Answer me this: If PLC isn't going to be cost-effective, why is the guy in this article so bullish on it? He's an employee of the power company and it's quite possible that his career rests on pulling this off.

As Southern Electric's Director of Telecoms His career may well already be tied to PLT.

to quote from the article

While PLC has a range of up to 300 metres, this can be extended simply by using "boosters" or "repeaters" located in homes and businesses that are closer to broadband-enabled electricity substations.

His descriptions of repeaters being fitted in customers houses does not fit with any known architecture for PLT.

The future of broadband in rural areas via electrical cables hinges on the success of a commercial trial that got underway in Winchester today.

As described PLT certainly does not appear to offer a realistic solution for rural broadband if a repeater is needed every 300m and does not explain how the system is going to work though transformers without having bridging work done on each transformer.

I am almost 100% certain that Winchester is on one of mainnet's systems and they certainly do not describe a system with repeaters in the customers premises to extend range
http://www.mainnet-plc.com/plus_architecture.htm

Barring massive shareholdings in a manufacturer, why would he take such a huge risk?
[/qoute]

Perhaps because His neck is already out too far on this or perhaps His company does have a stake in the company providing the PLT kit in which case they have to be positive if they are to have any chance of recouping their investment in a lame duck.

Brendan

spongebob

Your case for not running PLT equipment on overhead (exposed) lines is strong. Naturally all lines in rural areas are overground and you can therefore generalise (accurately) based on situations that arose in other countries.

Your argument against PLT in Rural areas translates into quite a good argument for PLT in Urban areas ......let me explain.

1. The tail Lines are Underground.
2. Installation of repeaters is a ground job
3. Extra shielding can be aded to substations with the equipment installed
4. Shorter 'hops' to each premises from the substations
5. The cost of the AccessMultiplexer is lower than a DSL equivalent on a per port basis.....part of which is negated by the repeater cost later on.

Care to comment on that

M

nahdoic

That's a very interesting point Muck.

PLT for an alternative last mile in urban areas.

Wireless for an alternative last mile in rural areas.

bminish

Originally posted by Muck
Your argument against PLT in Rural areas translates into quite a good argument for PLT in Urban areas ......let me explain.

1. The tail Lines are Underground.

[/i]

The majority of wiring in PLT is actually in the consumer's premises and not underground.

In Tuam like most older town wiring systems most of the 240v wiring is either on poles (shared with streetlights) or along the font of the buildings.

In most newer housing estates the supply wiring is indeed underground from the substation but the majority of wiring in PLT is actually in the consumer's premises and not underground, Don't forget every Cm of wiring in Every house in a PLT area ( wether or not they are a subscriber) is carrying AND radiating the PLT signals.

Underground PLT areas have proven to be every bit as serous a source of ' radio pollution'

Test area 3 in the ARRL video clip (Emmaus PA) is filmed in an underground PLT area

2. Installation of repeaters is a ground job

True.

3. Extra shielding can be aded to substations with the equipment installed

Substations are not the main source of the problem, Smaller ones are already inside well earthed metal boxes, it's all the wiring that is attached to them that does the radiating.

4. Shorter 'hops' to each premises from the substations

I have always said that the PLT people are really after the Urban market, so why do the keep trying to tell us that it's the answer for rural broadband, Something to do with gaining political support perhaps?

5. The cost of the AccessMultiplexer is lower than a DSL equivalent on a per port basis.....part of which is negated by the repeater cost later on.

But you still have to do backhaul and in any case DSL works very nicely in Urban areas, is a proven business model using proven technology and doesn't affect radio users.

spongebob

Originally posted by bminish
[/i]
Underground PLT areas have proven to be every bit as serous a source of ' radio pollution'

Test area 3 in the ARRL video clip (Emmaus PA) is filmed in an underground PLT area

Sound. Which of your (many) links demonstates this most clearly ?

M

dahamsta

First one in this list Muck:

http://www.arrl.org/tis/info/HTML/plc/#Video

adam

spongebob

Originally posted by dahamsta
First one in this list Muck:

http://www.arrl.org/tis/info/HTML/plc/#Video

adam

U are jokin Adam. !

That LINK above contains about 10 further links the first of which is

http://216.167.96.120/BPL_Trial-web.mpg 24MB MPG

the second is

http://216.167.96.120/BPL_Trial-small.mpg 7.5Mb

Come ON lads. Give it to me in 1Mb max.!

The SMALLER (7.5Mb) one shows a geezer in a red estate driving around a SUBURBAN area with lots of green in the background) and which is not inconsistent with PLT deployment in an URBAN area then ....is it. It is also BORING, it shows a dial hopping around. I could upload my holiday snaps to prove nothing at all ......except that they are boring snaps to you!

One or two CAREFULLY chosen links please ........bombarding us with ****loads of data in large globs is bloody annoying at this stage . If there is a case against PLT then don;t try to intimidate me with sheer volume, it won't work.

I'm sure that others have given up on the link overload by now.

M

bminish

Originally posted by Muck

One or two CAREFULLY chosen links please ........bombarding us with ****loads of data in large globs is bloody annoying at this stage . If there is a case against PLT then don't try to intimidate me with sheer volume, it won't work.

I am not trying to intimidate anybody with links.
When we first stated discussing this issue I was accused of possible bias and asked to provide links and references to substantiate my position.
Adam in particular asked me for deep links and I feel he was correct to do so, I am trying to do this. There a huge case against PLT from lots of angles, if you want just an overview then don't bother following the links but please don't rubbish the argument against PLT on the basis that there is too much information out there..

It seems that I can't win!

Where are all the links to happy PLT users talking about well it is working for them and how reliable it is?

In the video clip from trial area 3 you can hear nothing but noise at high signal strength. In a non PLT area you would hear lots and lots of stations in the same frequency rage, all of which are below the nose floor created by the PLT system in the trial area. The video footage assumes that you already know a little about HF radio.

The ARRL also made proper documented field strength measurements in the trial areas.


One link that deals quite well with the issue of PLT on underground and over-ground lines is report done by the UK radio authority Technical working group.

UK Technical Working Group (TWG) on Compatibility Between Radio Services and VDSL + PLT Systems Operating between 1.6 and 30 MHz
I won't link directly to it as it is a 6Mb PDF file and is quite technical. You can find the link to it on this page

http://www.radio.gov.uk/topics/interference/documents/dslplt.htm

It's up to you if you want to read it.

Incidentally the general consensus is that vDSL is unlikely to be a serous problem

Brendan

dahamsta

Originally posted by bminish
When we first stated discussing this issue I was accused of possible bias

Not you in particular Brendan, but the amateur radio community in general. And I didn't mean it in (a particularly) insidious way either, the suggestion was simply that the amateur radio community appears to have a lot to lose - their primary hobby in many cases - so it's possible that they would play up other failings to protect their hobby; the obvious ones being interference with critical emergency services and costs.

You can view this as a slur on the community if you want, but people are people, and people have done far worse in the past to protect their interests, and will continue to do so for long into the future. In this case, I honestly wouldn't hold much of a grudge against hams if it proved to be true*, since nobody wants to see a hobby you've spent a lot of time, energy and money on disappear. How about if we call it "Biased Like A Fox", does that help?

Muck, sweety, you asked for the video, I gave it to you. Would you like an apple pie with that?

adam

* Which isn't the same as saying I won't go out of my way to find out the truth; and won't shout and roar like a lunatic if I find out, for example, that the ARRL is telling porkies and amplifying and exaggerating that noise. For example. What's the position on that gain dial there? +11?

bminish

Which isn't the same as saying I won't go out of my way to find out the truth; and won't shout and roar like a lunatic if I find out, for example, that the ARRL is telling porkies and amplifying and exaggerating that noise. For example. What's the position on that gain dial there? +11?

Under normal quiet urban noise conditions running with the RF gain full open would be usual and the local noise floor would not move the meter except perhaps on some spot frequencies in small areas.

Rural areas are quieter than urban areas in general.

How low the ambient noise floor is depends on how wide a filter you use to measure with. Measuring the ambient noise floor on HF with a 9Khz filter will show a much higher figure than a 100 Hz filter.
100Hz is the typical bandwidth of a Morse code signal (yes we still use Morse extensively, it's fun and efficient.) , a PSK31 Signal is even narrower than this.
Single side band voice is generally considered to occupy around 2.8 Khz
9Khz is appropriate for narrow band FM signals on VHF.

The ARRL video shows the receiver in SSB mode with a standard SSB filter installed (~2.4 Khz bandwidth)

ambient noise floor measurements need to be carried out using the appropriate measurement bandwidths, the ambient noise floor should not be confused with the noise floor of the measuring apparatus.


Here is some information on this
http://www.qsl.net/rsgb_emc/emcslides.html


Brendan
(who still can't think of a sig)

spongebob

Originally posted by bminish

One link that deals quite well with the issue of PLT on underground and over-ground lines is report done by the UK radio authority Technical working group.

UK Technical Working Group (TWG) on Compatibility Between Radio Services and VDSL + PLT Systems Operating between 1.6 and 30 MHz
I won't link directly to it as it is a 6Mb PDF file and is quite technical. You can find the link to it on this page
http://www.radio.gov.uk/topics/interference/documents/dslplt.htm
Brendan

Brendan

I had come across this before. I am not an RF expert unlike the 'experimenting' community and do not have the key technical phrases needed to string search the document with ye olde CTRL+F key combination

It is 420 pages long ISTR

I assume that there is a summary of the key facts somewhere in the 420 pages. Could you refer me to those 1 or 2 pages that summarise the issue. If it was a 10 page PDF I would refer you to the precise page that summarised or supported a point that I felt like making based on that document but 420 pages is a tad too much ....even for me.

M

spongebob

I actually found this link Here which is a Html page.

It details all the nasty things that are found in the Average Household and which can output continous or intermittent noise in the bands between 0 and 60Mhz which are so valuable to the experimenting community and also to long distance emergency and communications frequencies . My 2.5Ghz pentium is probably howling in the MMDS band as I write this.

It'll probably take me a week to audit my own house for compliance, never mind what the ESB will be up to in September

M

bminish

Originally posted by Muck
Brendan

If it was a 10 page PDF I would refer you to the precise page that summarized or supported a point that I felt like making based on that document but 420 pages is a tad too much ....even for me.

M

These are complex issues and this is a report done by a technical body. I have not come across a summary of this document like you are asking for, however here are some notes from the RSGB on this paper.

this a PDF file (128k)
http://www.qsl.net/rsgb_emc/Notes%20on%20Fin%20Rpt%20Ver%201.pdf

To summarize on the points that started this.

PLT causes unacceptable levels of radio pollution to HF radio users. it's not just the amateur users Saying this, Broadcasting, defence, marine, Scientific, and aeronautical sectors are also deeply concerned. Various European standards and regulatory bodies are also extremely concerned by both the theoretical problems and the real world problems caused by the trials.

The levels of Junk put out by PLT are approximately the same in underground Power line areas as they are in Over-ground power line areas based on observation.

PLT radiates from all wiring carrying the PLT signals, the majority of wiring in any plt system not the distribution wiring but is all the wiring inside all the buildings in the PLT area.

If you want to understand the issues properly then you will have to wade through and understand a great deal of technical data.

If you want non-technical summaries you will have to accept what the Amatuer radio organizations are putting out. Almost all the other documentation out there is highly technical since it has been done for or by various technical bodies.

I don't see how you can have it both ways.

When Tuam goes live I plan to arrange a demonstration of the interference problem (& there will be an interference problem if the Tuam trials use any of the existing PLT technologies), I hope you would be interested in attending.

It would be also be very interesting to hear from PLT users once the system goes live.
I have yet to find any feedback from any PLT users from any of the many trials that have been or are being done world wide.

Brendan

spongebob

Try a before and after scan.

You seem to be aware of where the noise WILL occur in terms of location(s) on the spectrum.

Ask Eurorunner (lives near Tuam) if (s)he would witness a before and during the trial scanner demonstration in and around Tuam along with a few more locals if they will come.

EG if the likely suspect is 55Mhz then run a scan now with witnesses present and then go back when it is live and run the same scan again on 55Mhz and note the difference.

Running the scan in Tuam and outside Tuam would also help the case because you are pretty certain that it will propogate quite a distance.

M

bminish

Originally posted by Muck
I actually found this link Here which is a Html page.

It details all the nasty things that are found in the Average Household and which can output continuos or intermittent noise in the bands between 0 and 60Mhz
M

This is an entirely different issue!
Yes there are plenty of interfering devices but in general they are not connected to efficient antennas and are governed by CE rules (CE marked). CE rules tightly control levels and more importantly restrict very tightly how much junk is allowed get back into power lines.

In my house I have a lot of electrical Junk, 5 Running PC's (2 of which are next to and connected to my radio equipment) 100Mbs Cat 5 networking, Laser printer, Florescent lights, TV, Video, DVD etc. Except for a couple of spot frequencies where I have some problems from 1 older (non CE compliant) computer monitor I can hear all the way down to the quiet rural noise floor level

Urban noise floors are higher simply due to the larger amount
of noise generating devices. Current urban noise floors are WAY below PLT area noise levels.

Here is a link (HTML) that shows various noise floor levels alongside some proposed noise limits
http://www.qsl.net/rsgb_emc/emcslides.html

EMC issues with domestic and industrial equipment do arise and can usually be dealt with by some relatively simple measures, I.e fitting simple filters, improving grounds etc. Most of these nose issues are only a problem over a limited frequency range in a limited area and only an issue when the source of the noise is operational.

One source of interference we have had in Ireland was due to Eircom's Carrier systems, Comreg ruled that Eircom must fix these where they are causing problems to amateurs, our case was helped considerably by the fact that they aren't CE approved..

Currently the rules deal with interference caused by accidental emissions and in the real world the rules work reasonably well to protect HF users whilst not imposing excessive costs on equipment manufacturers.


PLT is different, it operates across the entire HF spectrum at the maximum level that they are permitted to use, is connected to a relatively efficient antenna system, covers a wide area and is operational 24 Hours a day. PLT emissions are not accidental, PLT simply cannot operate without generating emissions.

.Brendan

bminish

Originally posted by Muck
Try a before and after scan.

You seem to be aware of where the noise WILL occur in terms of location(s) on the spectrum.
M

Yes, the HF spectrum. 55 Mhz is low band VHF I would be surprised if the Tuam trials use one of the PLT systems that includes low band VHF since low band VHF is extensively used in Ireland.

Ask Eurorunner (lives near Tuam) if (s)he would witness a before and during the trial scanner demonstration in and around Tuam along with a few more locals if they will come.

Hopefully I will be in a position in a week or so to make some before measurements in Tuam, however Tuam will also need comparing with other Urban areas.
By the time I am ready to do meaningful measurements the system may already be partially operational.

I will video these measurements and of course witnesses are most welcome.

It would be interesting to know what the effects of HF radio transmission are on the PLT system in Tuam. In other trial areas PLT has been shown to be badly effected by even low power HF transmissions.

Quote from here http://www.arrl.org/news/stories/2003/08/21/4/?nc=1

The League also noted that comments in the proceeding so far have been silent on the interference susceptibility of BPL to ham radio signal ingress. The League predicted that even as little as 250 mW of signal induced into overhead power lines some 100 feet from an amateur antenna could degrade a BPL system or render it inoperative.

The Austrian trials showed similar results
quote from here http://www.darc.de/referate/emv/plc/c3.4-rev1-PLC5RPRT.pdf

This has been demonstrated during a PLC trial in Fulpmess/Tirol (Austria) where PLC could be blocked by less than 5 watts transmitter power (independant of the PLC transmitting level), thus confirming earlier reports of RSGB that PLC can be blocked by HF transmissions. But NB30 regulations say that "telecommunications operators using all kinds of cables have to tolerate interference from radio services", therefore under the NB30 regime in Germany no problems for amateur radio are expected because of this PLC deficiency. This result should also make clear that every future test on PLC installations conducted by radio amateurs should not only include listening (and measuring), but if ever possible also transmitting, to demonstrate this deficiency of PLC.

The probable trial area contains 2 active amateur operators and I intend to carry out my own transmitting experiments in the trial area.

Running the scan in Tuam and outside Tuam would also help the case because you are pretty certain that it will propagate quite a distance.

Up to 2 miles has been observed in other trial areas.
The global effects of widespread PLT deployment are currently unknown but here is growing concern that deployment in larger areas would raise the nose floor in other regions due to HF sky wave propagation
Would you like links with that


.Brendan

Eurorunner

Ask Eurorunner (lives near Tuam) if (s)he would witness a before and during the trial scanner demonstration in and around Tuam along with a few more locals if they will come.

Only too happy to help.

Unfortunately, dont know anyone who will be plt trialists in Tuam..i'm sure contact with an end user would also be useful so if anyones following this thread and is due to be an ESB plt guinea pig, please post here.