Power Line Telecomunications (PLT) Technology

dahamsta

Hams Complain about Powerline Broadband
Posted by michael on Friday August 08, @07:54PM
from the tinfoil-hats dept.
dwm writes "Think broadband over power lines (BPL) would be wonderful? There might be some collateral damage. The American Radio Relay League (your friendly neighborhood ham radio operators) have documented dramatic HF radio interference in areas where BPL is being tested (Check out the video of actual interference)."

As noted previously, Irish Ham operator Brendan Minish (EI6IZ) also posted commentary about this on ie.comp recently.

This is a difficult one to call. If Brendan's facts are right - I have no particular reason to doubt him or his sources, but PLT lobbyists aren't the only ones with an agenda here - and the technical hurdles and costs are extremely high, then I have to side with the Hams and say that there are better things to spend our taxes on. If they're not that high though, then I think we have to put progress on broadband ahead of what are ultimately hobbyists, for three very specific reasons:

1. Because we're so far behind in Ireland. I'd imagine that a lot of people don't think broadband is all that important, but I think it's enormously important, both socially (education, access, community) and commercially (competition, communication, buyin'n'sellin'), and I think drastic measures are called for. We need to accelerate rapidly, and this seems like a slightly flawed but enormously powerful (pardon the pun) way of doing so.
   
2. Because the the national grid still belongs to us. Rob Kemp (quoted by Brendan Minish) has a valid point when he says that operators will go for gold with PLT, however that's not as much a concern here as it is in the United States. Certainly the board of the ESB - a very canny bunch I reckon - will be choking at the bit to get into the high-population areas, but ultimately they have to serve their shareholders, and 95% of the shares are held by Gov.ie. Gov.ie can take a hit on this if they think it's needed. And they should...
   
3. Because if anyone can get a handle on this technology, it's the ESB. Don't get me wrong, I'm not saying that the ESB is the be-all and end-all of electricity suppliers, but they do seem to have their heads glued on very firmly indeed. The management seem to run the organisation very smoothly and the techs on the ground seem to be extremely competetent and capable -- remember, these guys are shipped off to the continent when Johnny Foreigner runs into trouble. (Bad joke, sorry.)

I don't disagree with Brendan on the wireless front. He's right, wireless is an excellent medium for in Ireland and I hope to see progress - a LOT of progress - here soon on that front. However the argument is contradictory to a degree, because wireless operators will aim for large population centers just like the powerline operators in the States, and Gov.ie's backing away from the second and third stages of the fibre rings project doesn't bode well here. The ESB can go end-to-end with delivery...

By the way, if anyone knows Brendan, I'd be delighted to see a response to this. I'm not going to post it on ie.comp because the thread is quite old at this stage. Mods, I didn't know whether this should be in a new thread or not, feel free to split it if you wish.

BTW, I don't mean to debase Hams when I call them hobbyists, I can see myself going for a Ham licence myself in a few years time, but ultimately we're weighing the enjoyment of a pretty small number of people against the progress of a nation. As to the contribution of Hams in emergency situations, I've seen (or rather heard) this at work personally on the Citizen's Band and I think it's amazing; and I agree that this valuable resource would probably die out in it's present form if PLT came to fruition, but there's no reason why an alternative network for use in emergencies couldn't be put in place by Gov.ie for a relatively small cost.

adam

oscarBravo

I've mailed Brendan - we'll see if he wants to add anything to the discussion.

[I don't exactly know Brendan, but I've communicated with him by email in the past.

dahamsta

Thanks oscarBravo.

Now that I come to think of it, this is flawed logic:

I agree that this valuable resource would probably die out in it's present form if PLT came to fruition, but there's no reason why an alternative network for use in emergencies couldn't be put in place by Gov.ie for a relatively small cost.

Of course if the intereference problem is as severe as outlined in the Slashdot piece, it would be extremely difficult to install an alternative, because it would be impossible to test. However there must be some alternative?

adam

bminish

Hello everyone and thanks to Paul for sending me over here.
I would like to respond to dahamsta's posting.

Originally posted by dahamsta
As noted previously, Irish Ham operator Brendan Minish (EI6IZ) also posted commentary about this on ie.comp recently.

--- Snip ---
If they're not that high though, then I think we have to put progress on broadband ahead of what are ultimately hobbyists, for three very specific reasons:
----

....
Actually there are quite a number of HF radio users besides the 1700 or so licensed Amateur radio operators in Ireland

Some that come to mind are

Marine users (trawlers, Ferries, pleasure boats etc) Safety of life at sea DEPENDS on MF and HF radio and the ability of the shore stations to be able to hear the vessels.

Aviation, all transatlantic Air traffic control is done on HF radio by Shanwick radio.

The Defence forces

Shortwave listeners (who listen to shortwave radio broadcasts etc.) The BBC and many other international broadcasters are deeply concerned about the impact of PLT
for more on the BBC's position on PLT see.
http://www.bbc.co.uk/rd/pubs/whp/whp012.html
and
http://www.bbc.co.uk/rd/pubs/whp/whp013.html

CB users

Some PLT systems extend up to 80 Mhz Almost all PMR (private mobile radio) in Ireland is on low band VHF. Users include
Taxis, Garda, Ambulance Service, Fire service, Vets, Doctors, delivery drivers etc.


Amateur radio has a serious side too, in 2001 I provided the communications for the Irish North west passage expedition, this included the handling of E-mail (over 2000 messages passed though here) and other digital data (Ice charts, weather maps and digital photographs)
Inmarsat besides being very expensive does not provide adequate coverage of the polar regions, the only means of communication with the boat was by HF radio from Ireland and it worked very well. It would have been completely impossible to communicate with the boat through the levels of interference that PLT generates
http://www.northabout.com/

Next year (PLT permitting) I hope to be able to provide a similar level of communication for the return voyage.

Originally posted by dahamsta

1. Because we're so far behind in Ireland. I'd imagine that a lot of people don't think broadband is all that important, but I think it's enormously important, both socially (education, access, community) and commercially (competition, communication, buyin'n'sellin'), and I think drastic measures are called for. We need to accelerate rapidly, and this seems like a slightly flawed but enormously powerful (pardon the pun) way of doing so.

   ---

   ...
   Firstly PLT will NOT provide rural broadband, it simply won't work over long distances. Two thousand feet of line is the upper limit. The UK trials were over a maximum distance of 600 feet.
   
   
   Most rural dwellers (myself included) are only one or two houses per ESB transformer, bridging the transformers to allow the PLT signals to the house will involve expensive live line work.
   
   Secondly there are already solutions for Rural broadband. I have been on a 2 way satellite system for the last 18 months and it works very well.
   I was recently involved with a project on InishTurk Island where a Satellite broadband system is shared with several users by means of 802.11b (Wi-Wfi ) wireless networking.
   
   Whilst I agree cheap broadband for all is a most desirable aim it is by no means essential to have broadband to make good use of the internet. Flat rate Dial up is perfectly adequate for many users in the near term and hopefully in the longer term there will be some better solutions (Wireless and improved telecoms infrastructure ) to improve access to broadband in rural areas.
   
   
   

   Originally posted by dahamsta

2. Because the the national grid still belongs to us. Rob Kemp (quoted by Brendan Minish) has a valid point when he says that operators will go for gold with PLT, however that's not as much a concern here as it is in the United States. Certainly the board of the ESB - a very canny bunch I reckon - will be choking at the bit to get into the high-population areas, but ultimately they have to serve their shareholders, and 95% of the shares are held by Gov.ie. Gov.ie can take a hit on this if they think it's needed. And they should...
   ----
   
   ...
   
   I am all in favour of competition but there are a couple of problems with your argument
   
   Why should what is effectively a state company be subsidized to compete in the lucrative urban broadband market, Surely this will not be good for the consumer in the long term as it may discourage other operators entering the market in these areas.
   
   
   The Urban market is ideally served by ADSL. Putting regulatory pressure on Eircom and possibly some subsidies for enabling smaller exchanges is a better way to go. You have a choice of ADSL providers in enabled areas. ADSL has a longer reach than PLT. The ESB would be a state subsidized monopoly and I don't think we want to go there again!
   
   The ESB are actually very well placed to get into the Wireless market as I outlined in my original usenet posting on this topic.
   
   

   Originally posted by dahamsta

3. Because if anyone can get a handle on this technology, it's the ESB. Don't get me wrong, I'm not saying that the ESB is the be-all and end-all of electricity suppliers, but they do seem to have their heads glued on very firmly indeed.
   ----
   ...
   The ESB cannot change the laws of physics!
   PLT does not have (and will never ever have) the ability to propagate very far down power lines. power lines are not designed to carry High frequency signals (hence the huge interference problem) and cannot realistically and cost effectively be improved in this regard.
   
   

   Originally posted by dahamsta
   
   I don't disagree with Brendan on the wireless front. He's right, wireless is an excellent medium for in Ireland and I hope to see progress - a LOT of progress - here soon on that front. However the argument is contradictory to a degree, because wireless operators will aim for large population centers just like the powerline operators in the States
   ----
   
   Well in the chorus wireless trials in the Limerick area, broadband service was available to people within 35 Km of the antenna site. There are plenty of good antenna sites that cover both rural AND urban areas,the ESB also already own masts on many of them as do Eircom, Esat, O2, RTE etc.
   
   
   
   

   Originally posted by dahamsta
   , and Gov.ie's backing away from the second and third stages of the fibre rings project doesn't bode well here. The ESB can go end-to-end with delivery...
   ---
   
   The ESB are well placed to get into the Internet business but I sincerely hope both as a HF radio user and as a rural dweller that the 'last mile' is bridged by wireless
   
   

   Originally posted by dahamsta
   
   BTW, I don't mean to debase Hams when I call them hobbyists, I can see myself going for a Ham licence myself in a few years time
   ----
   
   We are actually called Amateur radio operators or Radio Experimenters, HAM is a derogatory term dating back to the 1920's
   
   There won't be much point in getting an Amateur radio licence if PLT is widely deployed in Ireland
   

   Originally posted by dahamsta
   but ultimately we're weighing the enjoyment of a pretty small number of people against the progress of a nation.
   ---
   
   I hardly feel that the progress of the nation hangs on introducing another player into the URBAN broadband market. PLT will not help with rural broadband access and is an unsuitable technology due to it's serious impact on radio users.
   
   

   Originally posted by dahamsta
   As to the contribution of Hams in emergency situations, I've seen (or rather heard) this at work personally on the Citizen's Band and I think it's amazing; and I agree that this valuable resource would probably die out in it's present form if PLT came to fruition, but there's no reason why an alternative network for use in emergencies couldn't be put in place by Gov.ie for a relatively small cost.
   ---
   
   More tax payer subsidy to prop up an unsuitable technology!
   Can you please suggest a suitable alternative network!
   Building a truly nationwide communications system with redundancy, reliability and backup power would be enormously expensive, never mind the on-going maintenance costs, user training requirements etc.
   
   
   regards
   Brendan Minish (EI6IZ)

SkepticOne

Originally posted by bminish
The ESB are actually very well placed to get into the Wireless market as I outlined in my original usenet posting on this topic.

This would be good. What would be even better would be facilitating backhaul for competing wireless operators rather than getting into it directly themselves. This would allow for greater innovation through competition.

oscarBravo

Originally posted by bminish
Hello everyone and thanks to Paul for sending me over here.

No thang.

Amateur radio has a serious side too, in 2001 I provided the communications for the Irish North west passage expedition...

This is what makes this subject particularly interesting to me: my uncle was one of the crew on that expedition, and anyone who saw the documentary will understand how crucial the radio link was.

dahamsta

<dahamsta whips out his trusty swiss-army editplus plugin and sets to work>

Hi Brendan, and welcome to Boards.

Actually there are quite a number of HF radio users besides the 1700 or so licensed Amateur radio operators in Ireland

Fair enough, and the users you list are critical, but that bring up the question: Surely the police and emergency service techs would be up in arms over this also? Where are the press releases, technical articles and op/ed pieces from these guys?

Amateur radio has a serious side too

I don't doubt it, and I wouldn't be so crass as to suggest that amateurs don't take the "hobby" side seriously either, but are there really no alternatives? Does the interference cut across the entire HF bands? (I'm not being smart here, I just don't know enough about radio.)

Firstly PLT will NOT provide rural broadband, it simply won't work over long distances.

Not even with repeaters? Are repeaters prohibitively expensive?

Secondly there are already solutions for Rural broadband. I have been on a 2 way satellite system for the last 18 months and it works very well.

VSAT is good for email and not bad for the web but it's useless for anything that requires decent latency. Gaming isn't important to me, but it's important to many people; ssh is critical to me, and useless on a satellite connection. It's also horrendously expensive: you can do last-mile delivery over cheaper technology like 802.11, but the backhaul still adds up to a fair whack as compared to a leased line. Of course VSAT should really only be considered for extremely remote areas anyway.

Whilst I agree cheap broadband for all is a most desirable aim it is by no means essential to have broadband to make good use of the internet. Flat rate Dial up is perfectly adequate for many users in the near term

If by near term you mean a year, then I agree; but a year is no time. In a year, I'd imagine the majority of Internet users in the United States will be connecting via broadband, and the same will be true of other countries (already is in fact). Websites will become more broadband oriented, file transfers will get larger -- as a broadband user myself I have to conciously stop myself from sending large files to friends, and I've only been using it for a month or so. The United States and many Asian countries are leaving Europe behind, and Europe is leaving Ireland behind; both socially and commercially. With that in mind, I have to respectfully disagree with you: cheap broadband for all isn't just desirable, it's mandatory. How we do it is another matter entirely of course.

Why should what is effectively a state company be subsidized to compete in the lucrative urban broadband market, Surely this will not be good for the consumer in the long term as it may discourage other operators entering the market in these areas.

That assumes that PWL can't be rolled out to rural areas, something I'm not entirely willing to concede yet. (I don't mean this in a nasty way, I just feel the need to see more evidence first.) Even if we assume that it can't though, remember that there's very little competition in the urban market. Yes, you've got all these resellers out there, but the majority of the dosh still goes to Eircom. In the major urban centres you've also got wireless, but it's drastically overpriced outside the Pale, and it could be argued that it's dangerously over-subsidised inside the Pale. So with that in mind, why shouldn't we have a little more competition? If it's as lucrative as you say, we won't even need to subsidise the ESB!

The Urban market is ideally served by ADSL.

That's a very arguable point Brendan. In ideal conditions I'd agree with you, but Eircom's infrastructure isn't up to scratch. Fail rates are extremely high, and Eircom is refusing to answer questions about investment directly; in fact it's already threatened to withdraw investment (that it hasn't committed) at least once. (Search for 'billion eircom' on this forum.)

Putting regulatory pressure on Eircom and possibly some subsidies for enabling smaller exchanges is a better way to go. You have a choice of ADSL providers in enabled areas.

In reality you have a choice of two, Eircom and EsatBT, and that assumes EsatBT have lobbed DSLAMs into the relevant exchange. We still have an explicit duopoly at wholesale level, and an implicit cartel at retail level.

ADSL has a longer reach than PLT.

Not by much, but now I'm just being anal.

The ESB would be a state subsidized monopoly and I don't think we want to go there again!

Many here would argue that selling the wholesale arm of the state-subsidised comms monopoly was one of the biggest mistakes the Government has made in recent history. In fact, I think a few in Government would and have agreed with us.

The ESB are actually very well placed to get into the Wireless market as I outlined in my original usenet posting on this topic.

I agree with you, but I don't think they're considering it. I don't think they'd be trialling PLT if they hadn't been ordered to either, they don't seem to want to get involved in the comms market at retail level. It's possible they'd be right on a commercial level too, but it's a semi-state body, and with that comes responsibility. Personally speaking, I think that this is a Good Thing.

The ESB cannot change the laws of physics!



PLT does not have (and will never ever have) the ability to propagate very far down power lines. power lines are not designed to carry High frequency signals (hence the huge interference problem) and cannot realistically and cost effectively be improved in this regard.

I have to profess ignorance on this. How are the signals transmitted? Obviously not over fibre. Why don't they use fibre?

Well in the chorus wireless trials in the Limerick area, broadband service was available to people within 35 Km of the antenna site.

Muck's the man to go through this with you, no doubt he'll be along in a minute. Presumably this is in the licenced bands and I've really only been, ahem, briefed on 802.11, which operates to a radius of a few miles. AP numbers are restricted too.

We are actually called Amateur radio operators or Radio Experimenters, HAM is a derogatory term dating back to the 1920's

I did not know that. Shortly before I switched off my Citizen's Band radio for the last time over a decade ago, I was hanging around with a few amateur operators who called themselves and their colleagues Hams. It never seemed to bother them, but I apologise if I caused offense.

There won't be much point in getting an Amateur radio licence if PLT is widely deployed in Ireland

If the interference problem is as bad as you say, then I guess that's true.

More tax payer subsidy to prop up an unsuitable technology!
Can you please suggest a suitable alternative network!

Well, no. I did make this pretty clear in my follow-up post though.

Thanks for responding Brendan.

adam

spongebob

Originally posted by dahamsta
<dahamsta whips out his trusty swiss-army editplus plugin and sets to work>

well covered people.

Secondly there are already solutions for Rural broadband. I have been on a 2 way satellite system for the last 18 months and it works very well.

VSAT is good for certain functions, I must add my PcAnwhere to Adams ssh or anothers persons irc. It is useless for always on connections.

The ESB are actually very well placed to get into the Wireless market as I outlined in my original usenet posting on this topic.

Yes but they wont.

Well in the chorus wireless trials in the Limerick area, broadband service was available to people within 35 Km of the antenna site.

humm, Chorus may have said 35km and some may believe them. 15-20Km radius from a sectoral antenna (diameter of cell 35km then) is most feasible.

Thanks for responding Brendan.

adam [/B]

'

Hear Hear .

M

bminish

Originally posted by dahamsta


Hi Brendan, and welcome to Boards.


Thanks, how do you make posts look nice and spell check here? usenet is much easier ;-)



Actually there are quite a number of HF radio users besides the 1700 or so licensed Amateur radio operators in Ireland

Fair enough, and the users you list are critical, but that bring up the question: Surely the police and emergency service techs would be up in arms over this also? Where are the press releases, technical articles and op/ed pieces from these guys?

They ARE deeply concerned just read the responses to the various public consultations that are going on around the world in particular the UK radio authority and the FCC in the states.

Don't forget that the department of the marine or the Irish aviation authority have lots of clout. it's no coincidence that the trial areas are not coastal areas and that there are no airports in the vicinity .


Amateur radio has a serious side too

I don't doubt it, and I wouldn't be so crass as to suggest that amateurs don't take the "hobby" side seriously either, but are there really no alternatives? Does the interference cut across the entire HF bands? (I'm not being smart here, I just don't know enough about radio.)


Yes PLT covers the Entire Shortwave spectrum in extremely strong noise, only very strong signals will be heard over the top of it. PLT noise is constant and renders the entire HF spectrum pretty much unusable in the entire PLT area


Firstly PLT will NOT provide rural broadband, it simply won't work over long distances.

Not even with repeaters? Are repeaters prohibitively expensive?


Consider you need one at least every 2,000 feet and that they will have to be fitted by engineers able to do live line work on 10,000 volt lines, even if the repeaters are free it's still very expensive by the time they are installed.

Don't forget that DSL can be repeated too although it is expensive. Perhaps Comreg / irish Gov.COM could make broadband part of Eircom's universal service agreement, then you might see Eircom using some of the considerable microwave radio spectrum that is licensed to use for this purpose instead of sitting on it.


Secondly there are already solutions for Rural broadband. I have been on a 2 way satellite system for the last 18 months and it works very well.

VSAT is good for email and not bad for the web but it's useless for anything that requires decent latency. Gaming isn't important to me, but it's important to many people;

So you are suggesting that Gaming is more important than the entire HF radio spectrum?




ssh is critical to me, and useless on a satellite connection. It's also horrendously expensive: you can do last-mile delivery over cheaper technology like 802.11, but the backhaul still adds up to a fair whack as compared to a leased line.


PLT can't do backhaul and never will be able to as it has neither the range or the bandwith, the back haul has to be done over fibre or wireless



How we do it is another matter entirely of course.


PLT has not been viable in any market yet and is unlikely to be of much value here either.

Why should what is effectively a state company be subsidized to compete in the lucrative urban broadband market, Surely this will not be good for the consumer in the long term as it may discourage other operators entering the market in these areas.

That assumes that PWL can't be rolled out to rural areas, something I'm not entirely willing to concede yet. (I don't mean this in a nasty way, I just feel the need to see more evidence first.)


You won't find ANY successful trials of PLT that have reached further than 2,000 feet. It's all down to the physics. Read the trial reports on the Internet. run some google searches and see for yourself


ADSL has a longer reach than PLT.

Not by much, but now I'm just being anal.


DSL generally can go to around 16,000 feet of line, PLT can go to around 2,000 feet under ideal conditions, seems like quite a difference to me
ISDN can go to around 27,000 feet and ISDN repeaters can be used to extend this, my ISDN Line contains a repeater.


The ESB cannot change the laws of physics!



PLT does not have (and will never ever have) the ability to propagate very far down power lines. power lines are not designed to carry High frequency signals (hence the huge interference problem) and cannot realistically and cost effectively be improved in this regard.

I have to profess ignorance on this. How are the signals transmitted? Obviously not over fibre. Why don't they use fibre?

if PLT used fibre there would be no problem whatsoever to radio users Fibre to the home is expensive to install but would be by far the best possible long term solution for broadband Internet, cable tv etc.

PLT works by sending wide band spread spectrum radio signals down the power lines but since power lines make very good antennas this creates an enormous radio pollution problem and covers the entire HF radio spectrum with very strong noise which is always present and on all frequencies

IF ADSL was put out over untwisted pairs it too would be a radio interference problem but since balanced twisted pairs are very good at keeping the signals from being radiated there is no interference problem



Muck's the man to go through this with you, no doubt he'll be along in a minute. Presumably this is in the licenced bands and I've really only been, ahem, briefed on 802.11, which operates to a radius of a few miles. AP numbers are restricted too.


There's plenty of licensed spectrum available for interested parties at reasonable cost, equipment is already made by the likes of cisco and the licensed kit can cover many miles but is more expensive than the 802.11b stuff


We are actually called Amateur radio operators or Radio Experimenters, HAM is a derogatory term dating back to the 1920's

I did not know that. Shortly before I switched off my Citizen's Band radio for the last time over a decade ago, I was hanging around with a few amateur operators who called themselves and their colleagues Hams. It never seemed to bother them, but I apologise if I caused offense.


You have cased No offence to me but it does offend some.


There won't be much point in getting an Amateur radio licence if PLT is widely deployed in Ireland

If the interference problem is as bad as you say, then I guess that's true.


There is some video footage on the ARRL website

http://www.arrl.org that shows how bad it is in the trial areas in the US, only extremely strong signals can be heard above the noise.

I intend making before and after measurements with professional test equipment in Tuam and I also hope to work with Amateurs and Shortwave listeners in the Tuam area to ensure that any problems caused by the trials get properly reported to the relevant parties, after all that's what a trial is about.
I am also very thankful indeed that I am not actually in a trial area



More tax payer subsidy to prop up an unsuitable technology!
Can you please suggest a suitable alternative network!

Well, no. I did make this pretty clear in my follow-up post though.


I was just trying to point out that it isn't a trivial problem to solve and that Amateur radio's greatest asset in emergency situations is the skill, flexibility and technical expertise of the Amateur operators.

regards
Brendan Minish (EI6IZ)

TomF

I've been an amateur radio operator since 1955, and the bands this interference seems to be hitting bad are some of the favorites of hams: I mean the 20 and 40 meter bands. 20 meters is a great band for DX (getting around the world and making contacts with exotic locations and getting interesting QSL cards).

I know one of the great concerns of hams when TV came in was television interference and much of that was caused by poor design of the TV sets, not the hams. Now it looks as though it is the hams who will have to be the complainers about other services interfering with radio reception.

spongebob

If the 'experimenting' persons were to use their expertise to help sppread ubiquitous Wireless BB nationwide (licenced and Unlicenced) then I would personally help all I could with the potential problem with the sub 80Mhz yowl that you guys are afraid of.

A Coalition of interests as it were. We can come to an understanding very quickly IMO

M

bminish

Originally posted by Muck
If the 'experimenting' persons were to use their expertise to help sppread ubiquitous Wireless BB nationwide (licenced and Unlicenced) then I would personally help all I could with the potential problem with the sub 80Mhz yowl that you guys are afraid of.

A Coalition of interests as it were. We can come to an understanding very quickly IMO

M

I think you will find quite a few of us very willing to help. I have done quite a bit of mucking around with 802.11b stuff including the community project on InishTurk Island.

There is a long history of amateur experimentation with high speed data on the microwave bands. back in 1987 I saw a project that managed 2mb/s on 10 Ghz that was pretty affordable. I didn't see much use for that kind of bandwidth back then though :-)

One potential problem is that the national and international rules governing Amateur radio strictly prevent commercial traffic and tightly regulate non commercial 3rd party traffic. This makes it illegal under most circumstances to use the amateur bands (such as 10 Ghz) to provide Internet access or do the back hauls.

There is nothing preventing us using our technical expertise to good use on other licensed bands (or indeed licence exempt spectrum). Quite a few of us have access to good radio sites also. Lots of Amateurs want broad band Internet access too.

Personally I would be very interested in being involved with broadband access on some of the licensed spectrum that has been made available however I don't understand enough about the economics to work out what is viable and what isn't as a commercial venture.

Brendan

dahamsta

Thanks, how do you make posts look nice

http://boards.ie/vbulletin/misc.php?action=bbcode

and spell check here?

I use my brain and occasionally Encarta.

usenet is much easier

I don't think so. It's just different. I'd prefer to communicate on mailing lists, but such is life.

They ARE deeply concerned just read the responses to the various public consultations that are going on around the world in particular the UK radio authority and the FCC in the states.

Well, sure, point me to them. I'll come back to this in a moment.

Don't forget that the department of the marine or the Irish aviation authority have lots of clout. it's no coincidence that the trial areas are not coastal areas and that there are no airports in the vicinity .

Prove it.

Yes PLT covers the Entire Shortwave spectrum in extremely strong noise, only very strong signals will be heard over the top of it. PLT noise is constant and renders the entire HF spectrum pretty much unusable in the entire PLT area

I'll come back to this in a moment too.

Consider you need [a repeater] at least every 2,000 feet

I'll need to look into how the electricity network works in more detail. How far from customer premises are transformers on average?

and that they will have to be fitted by engineers able to do live line work on 10,000 volt lines

You mean like the guys that work for the ESB?

Don't forget that DSL can be repeated too although it is expensive.

It's probably more cost-effective to put DSLAMs in the street cabinets.

Perhaps Comreg / irish Gov.COM could make broadband part of Eircom's universal service agreement

This isn't going to happen. We don't even have a basic data-rate obligation at the moment, Eircom can officially tell you to bugger off if you can't connect to the Internet.

then you might see Eircom using some of the considerable microwave radio spectrum that is licensed to use for this purpose instead of sitting on it.

And pigs might fly.

So you are suggesting that Gaming is more important than the entire HF radio spectrum?

Are suggesting that amateur radio is more important than the progress of a nation? (This is a circular argument. I already said this but I was also quite clear that I think this is the case /only/ if other issues can't be resolved. The same should apply to gaming.)

PLT can't do backhaul and never will be able to as it has neither the range or the bandwith, the back haul has to be done over fibre or wireless

And the ESB has a substantial fibre network.

PLT has not been viable in any market yet and is unlikely to be of much value here either.

Winchester seems to have gone mainstream now?

You won't find ANY successful trials of PLT that have reached further than 2,000 feet. It's all down to the physics. Read the trial reports on the Internet. run some google searches and see for yourself

Well, no. This is where I come back to "I'll come back to this in a moment". Sorry if I'm appearing a little snippy, but that's not how things work around here. I get this from watching proceedings on the Politics board here on Boards.ie: You're not allowed just refute something there, you need to provide links and a body of evidence to prove your point. Telling someone to read a report without pointing to it doesn't qualify, and neither does telling someone to Google. I wouldn't know where to start, whereas you obviously do -- help a guy out.

DSL generally can go to around 16,000 feet of line, PLT can go to around 2,000 feet under ideal conditions, seems like quite a difference to me

My mistake, I thought we were talking meters. My apologies.

if PLT used fibre there would be no problem whatsoever to radio users Fibre to the home is expensive to install but would be by far the best possible long term solution for broadband Internet, cable tv etc.

PLT works by sending wide band spread spectrum radio signals down the power lines but since power lines make very good antennas this creates an enormous radio pollution problem and covers the entire HF radio spectrum with very strong noise which is always present and on all frequencies

That's very useful, thanks. My confusion really stems from /where/ radio will be used on their network. Obviously it will be done at local level, but as I mentioned above, I don't know what local level /is/. I'll look into electricity networks this evening if I get a chance.

There's plenty of licensed spectrum available for interested parties at reasonable cost, equipment is already made by the likes of cisco and the licensed kit can cover many miles but is more expensive than the 802.11b stuff

Again, I think that wireless is one of the major routes forward, but it's not without problems either. For example, consumer perceptions of the radiation generated by wireless is going to be a major hassle for wireless operators as it gets more prevalent. You and I know that it's not harmful, but try telling that to a soccer mom when you're mounting an antennae on the local primary school. (/me stares lovingly at the roof of the local primary school)

You have cased No offence to me but it does offend some.

I'm only talking to you, so that's ok.

There is some video footage on the ARRL website

Seen it, it sounds terrible, but again, that's just one organisation (that I've seen). Have the results of the FCC BPL NOI enquiry been released yet? The results of that should be interesting. So should the ratio of amateur radio respondents to other respondents.

I intend making before and after measurements with professional test equipment in Tuam and I also hope to work with Amateurs and Shortwave listeners in the Tuam area to ensure that any problems caused by the trials get properly reported to the relevant parties, after all that's what a trial is about.

Good stuff, look forward to reading about it. It'd be cool if you'd post the results here when you're done compiling the information. And yes, that's what a trial is about, if it interferes with important services, then yes of course it'll need to be looked at again.

am also very thankful indeed that I am not actually in a trial area

Bit premature when you haven't tested yet, eh? You're not going in with a bias now are you?

I was just trying to point out that it isn't a trivial problem to solve and that Amateur radio's greatest asset in emergency situations is the skill, flexibility and technical expertise of the Amateur operators.

I don't deny that. You didn't answer my question though.

adam

dahamsta

With reference to your last post Brendan, if you haven't already have a chat with some of the people in IrishWAN or CorkWAN. CorkWAN will have more professional network engineers, radio guys and techies, but also more arguments (because of the network engineers, radio guys and techies). These people would be absolutely delighted to talk to you, they need all the help they can get and a few radio guys would be a boon to them. Perhaps the Irish amateur radio association (presumably there's an association) could arrange a seminar or something?

adam

spongebob

Originally posted by dahamsta
Perhaps Comreg / irish Gov.COM could make broadband part of Eircom's universal service agreement

This isn't going to happen. We don't even have a basic data-rate obligation at the moment, Eircom can officially tell you to bugger off if you can't connect to the Internet.

then you might see Eircom using some of the considerable microwave radio spectrum that is licensed to use for this purpose instead of sitting on it.

And pigs might fly.

Oh Dear. I must side with Adam on the above.

The Unioversal Service Data Obligation has dropped from 2400 Bits Per Second to 0k since the 25th of July. Broadband was never goiing to make it in anyway, maybe in 2012.

Eircom gets spectrum dumped on it by Comreg for want of a better description of the regulatory process (2.2Ghz 2.3Ghz 3.5Ghz in the NLOS spectrum alone to give an example). It then squats on it as a denial of service strategy and ties a weak regulator up in knots about it. The regulator cannot force them to offer services , strictly in accordance with their licence agreement EVEN where it is claimed and accepted by Comreg, based on Eircoms compliance reports the the spectrum IS in use.

The other 80% of the country gets nothing usable from Eircom in the NLOS bands.

We can still do a deal though How bout that conference Adam suggested you lot ? You guys host it of course and we'll all stay around fro the ritual sacrifice of Adam (its your turn) on the Hill of Tara afterwards....and crack a tinnie or two.


M

oscarBravo

Originally posted by Muck
Oh Dear. I must side with Adam

/oscarBravo checks Muck's temperature...

dahamsta

Crack the tinnies first and I'll bring my own knife.

adam

spongebob

and get DeV over to tell them about BoardsBand while we are at it.

Put in perspective.

Brendans Point!

Powerline kills off a very valuable slab of spectrum in the 0-80Mhz band.

Comreg will auction (fluffily) 40Mhz of very usable NLOS spectrum over the next month. Announced today see

http://www.comreg.ie/_fileupload/publications/ComReg0397.pdf

There will be a total of 450Mhz out of 1Ghz for unlicenced or licencing lite in the 5Ghz band by next year.

We data people could have 500Mhz coming into use while the 'Experimenters' want 80Mhz and even then they only really want part of it .

We can do a deal

M

bminish

Originally posted by dahamsta


Well, sure, point me to them. I'll come back to this in a moment.`

Well you could try following some of the links I have been giving out in previous posts or even try a google search. both the FCC consultation (currently ongoing) and the UK radio authority consultations are available on line. The IEE also has a consultation process ongoing but it's currently members only.
Following trials in Japan PLT was denied permission to operate.

Some starting links
RSGB PLT pages
http://www.rsgb.org/emc/pltnew.htm

ARRL PLT pages
http://www.arrl.org/tis/info/HTML/plc/

DARC PLT pages
http://www.darc.de/referate/emv/plc/

BBC PLT pages
http://www.bbc.co.uk/rd/pubs/whp/whp012.html
http://www.bbc.co.uk/rd/pubs/whp/whp004.html
http://www.bbc.co.uk/rd/pubs/whp/whp013.html


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


Please do some of your own legwork since you clearly consider the amateur radio community biased against PLT.
Don't forget that is isn't the first time PLT has been tried, in every single trial so far it has caused serious interference to HF radio in the trial areas. It is highly unlikely that the Irish trials will prove ANY different in this regard.

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

Don't forget that the department of the marine or the Irish aviation authority have lots of clout. it's no coincidence that the trial areas are not coastal areas and that there are no airports in the vicinity .

Prove it.

No PLT trial anywhere in the world has been carried out anywhere near aviation or marine sites. You can read the responses to the various consultations in other countries from the aviation and Maine sectors for yourself.

Of course I can't prove anything in relation to the Irish trials except that the radio people in comreg are very concerned about the radio pollution problem of PLT and publicly stated last year that they are not in favour of increasing interference limits to facilitate PLT in Ireland.
It would be highly irresponsible of the regulator to allow PLT trials in any area where safety of life or property relies on HF radio.

Consider you need [a repeater] at least every 2,000 feet

I'll need to look into how the electricity network works in more detail. How far from customer premises are transformers on average?

in urban areas it's often 1 big transformer per estate, in rural areas it is one or 2 houses per transformer fed by 10,000 volt lines. there is no fibre anywhere on the ESB 10 kv network

You mean like the guys that work for the ESB?

yes but live line work is slow and potentially dangerous. Not all ESB people do live line work.

And the ESB has a substantial fibre network.

Yes but not on the rural 10kv network

PLT has not been viable in any market yet and is unlikely to be of much value here either.

Winchester seems to have gone mainstream now?

to quote from their FAQ
----
We are in advanced stages of our trials on a technical level and early stages on a commercial level. The results of the pilots in Stonehaven and Winchester will shape our future roll out plans.
----

the last report I heard on the Winchester system was that they had enabled one housing estate which is served by underground mains wiring (underground wiring reduces somewhat the interference problem ) and that the maximum reach in this trial was around 600 feet.

I wouldn't know where to start, whereas you obviously do -- help a guy out.

I have provided plenty of links so far, perhaps you aren't following them deep enough. Let's try again.

Firstly on the compatibility issue between PLT and Radio users
these file from the UK radio authority technical working group

http://www.radio.gov.uk/topics/interference/documents/dslplt.htm
there is a lot of technical stuff here, this is one of the links from the RSGB web page on PLT


On distance covered, the equipment manufacturers are cagey about this as they are politically lobbying for PLT as a rural solution as this is most likley to win over the politicians, I have yet to find any trials anywhere in which the system worked successfully as a broadband access technique (I am calling broadband 512 kbs as this is the generally accepted figure I belive) over distances of more than 2,000 feet. I can find no instances where PLT has been trialed in a rural area.

There are many good technical reasons why PLT will not work over greater distances than around 2000 feet, it is hard to even to begin to explain them accurately to people without a radio / electronics background as you need to have enough technical knowledge to understand the answers. I am willing if necessary to give it a go however you will need to do your own background research too.

here are some PLT equipment manufacturers web sites please remember the manufacturers are only interested in putting good spin on PLT so read carefully!
Every one of these sites are short on hard facts and technical specifications.

Mainnet
http://www.mainnet-plc.com/

Ascom
http://www.ascom.com

Plexon
http://www.plexeon.com/power.html

That's very useful, thanks. My confusion really stems from /where/ radio will be used on their network. Obviously it will be done at local level, but as I mentioned above, I don't know what local level /is/. I'll look into electricity networks this evening if I get a chance.

Radio frequencies are used from the PLT equivalent of a DSLAM to the customer premises (and of course all the other houses who are connected to the same mains supply )

For example, consumer perceptions of the radiation generated by wireless is going to be a major hassle for wireless operators as it gets more prevalent. You and I know that it's not harmful, but try telling that to a soccer mom when you're mounting an antennae on the local primary school. (/me stares lovingly at the roof of the local primary school)

This is simply an education issue, by no means insurmountable. Comreg do field strength surveys of various transmitter installations every year, this year they are doing their biggest ever survey, over 400 sites will be surveyed. I have even submitted my own amateur radio installation as a site for this survey (we have to meet field strength limits too)

There is some video footage on the ARRL website

Seen it, it sounds terrible, but again, that's just one organisation (that I've seen). Have the results of the FCC BPL NOI enquiry been released yet? The results of that should be interesting. So should the ratio of amateur radio respondents to other respondents.

Since amateurs have to respond as individuals to these consultation processes it is not surprising that there will be lots of individual responses from Amateurs especially with an issue that is so important to the future of HF radio.

The ARRL footage shows wideband interference levels that make HF radio use almost impossible, only very strong signal levels would be heard above that racket. For the benefit of the other amateurs reading this signal levels were in excess of S9 at all times as received on a short mobile whip.

. And yes, that's what a trial is about, if it interferes with important services, then yes of course it'll need to be looked at again.

Just as you happen to feel (& I pretty much agree with you on this point !) that better broadband access is important, I also happen to feel that PLT is not worth trashing the entire HF radio spectrum for. PLT will not revolutionize Internet access in any case.
apparently I do not share your view of what are considered important services.

Suppose your next door neighbor was to replace his ESB supply with a noisy and smelly diesel generator in the back garden, would that be OK?

am also very thankful indeed that I am not actually in a trial area

Bit premature when you haven't tested yet, eh? You're not going in with a bias now are you?

There have been enough trials done to show that PLT always causes serious problems to HF radio users, if Tuam proves different you can be sure that I will report this finding too.

I don't deny that. You didn't answer my question though.

Which question was that then?

Brendan

bminish

Originally posted by Muck
and get DeV over to tell them about BoardsBand while we are at it.

We can do a deal

M

No need to do a deal, we want broadband as much as everyone else, we are mostly a techical buch who use computers and the internet just like everyone else here.

dahamsta

Heh, BoardsBand is the Boards.ie... Band Brendan. As in musical. Ignore Muck, he lives under a bridge.

Thanks for the comprehensive post, the deep links are exactly what I was looking for. (I'm an Internet consultant and a news addict, I spend all day surfing the web, so it can be painful to go looking for technical stuff that can be hard to find and difficult to understand.) The question, the question... Ah yes, the question was something along the lines of: Is there /really/ no alternative? Will it wipe out /everything/ in the HF bands? Will it /really/ make it unusable or is there a little bit of exaggeration going on?

You may already have answered this but I'm just preparing myself for the three S's, a munch and beer, so I just skimmed your response. Be back tomorrow if the hangover isn't too bad. Thanks again for taking the time to come here and help me understand this, I appreciate it.

Oh by the way, I understood what "S9 ... on a short mobile whip" meant!

adam /bursts with pride

bminish

Originally posted by dahamsta
Ah yes, the question was something along the lines of: Is there /really/ no alternative?

What makes the HF spectrum completely unique is the fact that it is reflected from the Ionosphere. This allows for local (into the next valley), national and international (worldwide) communications to take place without the need for relay stations or satellites.
Here is a flash primer on HF radio wave propagation
http://www.ae4rv.com/tn/propflash.htm

HF radio equipment is usually modest in it's power needs (car battery for example) and antennas can be erected easily in most locations.

VHF, UHF and microwave are line of sight + a little refraction and some local reflections to increase range a little

At sea line of sight isn't very far and there are no local obstacles to provide reflections hence the continuing use of MF and HF radio for deeper sea vessels.
Satellite systems are complex, expensive, generally require accurate dish pointing (hard on a small vessel / heavy seas)

HF radio is the primary means of Air traffic control for all flights that go more than about 200 miles away from land. 200 miles is about the limit of line of sight from jet planes at cruising altitude.

HF radio is still extensively used for shortwave broadcasting, A €30 tranny with shortwave coverage will be able to pick up English broadcasts directed to Europe from about 40 countries. There are plans afoot for a new Digital HF broadcasting standard that will improve reception quality.

Amateur HF is used extensively to provide E-mail access for boaters with Ham licences from anywhere on the planet.
http://www.winlink.org/

This system has developed several commercial spin offs which operate in the commercial marine HF allocations. These systems owe much of their R&D to the Amateur community's ongoing experimentation with digital communications over HF radio.

http://www.sailmail.com/
http://www.globewireless.com/
http://www.kielradio.de/
http://www.goals.com/sailscin/pinoak/podmain.htm

Much of the best and latest hardware for HF digital communications has been designed and tested extensively by Amateurs.
http://www.scs-ptc.com


Systems like flashcom allow container freight to be tracked to be tracked over large distances without the need for complex 2 way satellite communications

HF RFID tag systems allow tracking goods in warehouses (although most RFID systems are on UHF there are some that use HF at around 13.5 Mhz)

HF radar provides over the horizon coverage both for military applications and for scientific applications such as measurement of wave height and ionospheric disturbances

We are still finding plenty of new uses for the HF spectrum

HF radio is not obsolete by any means and we should not do anything to render this scarce and heavily used resource any less useful.

Will it wipe out /everything/ in the HF bands? Will it /really/ make it unusable or is there a little bit of exaggeration going on?

During the Irish north west passage expedition I made contact with the boat over 200 times, on most occasions signals were quite weak, S9 noise would have made contact impossible on all but a handful of occasions.

Your €30 euro tranny will not be able to pick up many shortwave broadcasts through that much local noise.

The BBC recommendation is that any system that raises the local noise floor by more than 0.5 dB should not be permitted as it has a negative impact on HF users.

results and measurements from other PLT trials show that HF radio is pretty much wiped out in vicinity the PLT systems. The interference is so severe because un-balanced, widely spaced power lines are not able to effectively contain the PLT signals. This is Why power lines are unsuitable for carrying wide band data.

Balanced Twisted pair (cat5, phone lines etc) are able to carry data long distances with little or no impact on radio users because they are very effective at containing the signals.

Oh by the way, I understood what "S9 ... on a short mobile whip" meant!

then you probably also understand that this problem will be even worse when measured on a full size dipole antenna

regards
Brendan

spongebob

Originally posted by bminish
UK radio authority
http://www.radio.gov.uk/topics/interference/documents/dslplt.htm

Please do some of your own legwork since you clearly consider the amateur radio community biased against PLT.

Indeed Brendan, I see you neglected to tell us that VDSL also interferes with the HF band.....as mentioned somewhat more prominently in that Radio Authority links you posted.

No VDSL plans in Tuam then

That working group convened after Streetlights started a big hum in Manchester during a Nortel/Norweb trial ISTR

I never realised that yiz experimenters has a whole class A all to yeerselves, http://www.ampr.org/amprnet.html and a whole Class B in Ireland alone sez this http://noh.ucsd.edu/~brian/amprnets.txt

wow!


M

bminish

Originally posted by Muck
Indeed Brendan, I see you neglected to tell us that VDSL also interferes with the HF band.....as mentioned somewhat more prominently in that Radio Authority links you posted.

I didn't mention it for 2 reasons

1/ this thread is about PLT

2/ the VDSL problem is nothing like as severe as the PLT problem, the impact of VDSL is relatively minor and the telcos themselves have to work pretty hard keep problems down to a minimum so that the cross talk between lines doesn't cause huge problems for them.
Telephones lines are balanced twisted pair and as long as the balancing is accurate and there are no nasty impedance bumps or other dodgey bits (all requirements for successful VDSL anyway) the impact of VDSL is minimal.

I never realised that yiz experimenters has a whole class A all to yeerselves, http://www.ampr.org/amprnet.html and a whole Class B in Ireland alone sez this http://noh.ucsd.edu/~brian/amprnets.txt

Yes you will see my old call (ei4dpb) listed someplace, I ran tcp/ip over VHF packet radio back in 1988 and 1989 when I was in College in Dublin. We even had an Internet wormhole though the waterford RTC.
some of the early Internet experimenters (pre web by a few years!) may remember using the KA9Q tcp/ip package to do TCP/IP on 286 class machines running dos.

Phil (KA9Q) is still around doing interesting stuff see
http://www.ka9q.net/

These days I run an Internet connected packet radio node and Dxcluster here in Castlebar Co, Mayo
unfortunately packet radio never moved on from 1200baud semi duplex in Ireland, however 1200bd is still adequate for such things as Dxclsuter access (a kind of specialized worldwide group chat for hams) and APRS (automatic position reporting system )

to see the sort of thing that goes around on the world wide DXclsuter network see
http://oh2aq.kolumbus.com/dxs/

APRS is kind of useful for some things too ( Paul, that's how we did the current position page for Northabout in 2001)

you can see me here
http://map.findu.com/ei6iz

Brendan.

SkepticOne

Originally posted by bminish


These days I run an Internet connected packet radio node and Dxcluster here in Castlebar Co, Mayo
unfortunately packet radio never moved on from 1200baud semi duplex in Ireland, however 1200bd is still adequate for such things as Dxclsuter access (a kind of specialized worldwide group chat for hams) and APRS (automatic position reporting system )[/B]

Wow, that is slow!

spongebob

Brendan has me hyperlinked outta it , I'll let Adam read them because its all his fault

bminish

Originally posted by SkepticOne
Wow, that is slow!

It depends on what you need it to do. The nice thing about 1200 Bd packet is that it is quite forgiving of multipath and works quite well on non-line of sight paths.

typical DXcluster sessions only use a few hundred bytes per minute. APRS traffic consists mainly of position reports, say 65 bytes every 10 minutes or so.

a 1200bd packet node can support quite a few users under those conditions.

in the heyday of the packet BBS system many of the backbone links were 9600 or 19200 Bd.

In countries such as Germany and slovenia where there are a lot more packet radio users they now have 2Mbs links in and many end users are connecting at 64 Kbaud

Brendan

SkepticOne

Originally posted by bminish
In countries such as Germany and slovenia where there are a lot more packet radio users they now have 2Mbs links in and many end users are connecting at 64 Kbaud.

Can this be applied to Ireland. Are there restrictions on transit of internet traffic? If so, what is the rationale?

spongebob

Not to mention a couple of oul spare IP ranges for Irishwan

bminish

Originally posted by SkepticOne
Can this be applied to Ireland. Are there restrictions on transit of internet traffic? If so, what is the rational?

Amateur radio has to operate within the rules that govern us. 3rd party traffic is pretty restricted (that's handling traffic for non Amateurs.)
Commercial traffic is strictly prohibited as is encryption although you are allowed use encryption on control links for remote repeaters.
The rational is that Amateur radio exists for the purpose of self training and experimentation, not to compete with commercial radio based services, this policy dates back to the earliest days of amateur radio.

That is not to say of course that the various techniques, software, equipment expertise etc cannot be put to good use on non-Amateur frequencies providing of course any amateurs involved stay within the relevant radio regulations.


As far as the ampr.org IP address block goes, it's an allocation to amateurs that dates back to the very early days of the Internet. The IP addresses in this rage can only be allocated to licensed amateurs. see
http://www.ampr.org/amprnet.html

sorry about that

. Brendan

Xian

Originally posted by SkepticOne
Wow, that is slow!

... better than the USO, though!

Brendan, I'll take the opportunity here to thank you for your excellent contribution - you'll understand it if it takes us a week to bury through the links you've posted!