Jump to content
Sign in to follow this  
Followers 0
Gloom

Please submit comments on BPL/PLC

Recommended Posts

I know this is a little off topic, but it seems that the word has not gotten out yet.

 

There is a new concept being tried to bring broadband to more people. PLC, or Power Line Communication. This uses existing power lines to send data communication to homes and offices. Sounds like a good idea right? Well the problem is, the powerlines also act as huge antennas and cause interference to large parts of the HF spectrum.

 

please read more about it here:

http://www.eham.net/articles/5316

 

and here:

 

http://www.arrl.org/news/stories/2003/04/25/1/?nc=1[/url]

 

and how to comment here:

http://www.eham.net/articles/5603

 

thanks for your time.

 

Gloom

 

----

Never let Common Sense Get in the Way of Determination.

Share this post


Link to post

The jury is still out on this info.

 

I work for a power company. I am also a ham. Believe me when I say I will be shouting down the house if I even THINK I might be getting interferance from the power company.

 

Having said that, my (and EVERY one AFAIK) power company is already using the lines to control the system. Likely the one near you does also. If we have not had problems yet, it proves that it MIGHT be possible to do this.

 

Out here in the west, there are thousands of computer users that would love to have broadband, but are lucky to get 24k on a loooooong phone line.

 

Good technically qualified hams are looking at this closely in the test areas. They will find and identify the problems if any exists. This reminds me of the big cable interferance scare of the 80s. It just didn't happen.

 

Keep your ears open, but don't have a cow man.

 

Mike. Desert_Warrior (aka KD9KC).

El Paso, Texas.

 

Citizens of this land may own guns. Not to threaten their neighbors, but to ensure themselves of liberty and freedom.

 

They are not assault weapons anymore... they are HOMELAND DEFENSE WEAPONS!

Share this post


Link to post

As another ham who works for a power company, let me add that we not only use our lines for data, we sell excess capacity to others.

 

The potential interference is possible, but not a certainty. There is no reason to beleive there will be as much interference from PLC than from current wireless networking.

 

Personally, I'm a lot less concerned about PLC RFI than the good-buddies with modified CB rigs splattering all over the spectrum.

 

Dave_W6DPS

 

My two cents worth, refunds available on request. (US funds only)

Share this post


Link to post

The impression I've gotten is that the current "control" usage of PLC is at a much lower frequency than the broadband version of it is expected to be. This makes sense, since Internet access would involve pushing grunches more data over the lines. Also, the potential for Amateur Radio to interfere with PLC was the rationale the FCC gave for denying the ARRL's request to add the 136 KHz band.

 

Can either of you guys shed some light on that aspect of it?

 

-----

~ Boyd

N5CTI

 

"Never ask a man where he's from. If he's from Texas, he'll tell ya soon enough. If he ain't, don't embarrass him."

Share this post


Link to post

No, nothing firm yet. I am in a wait-and-see mode. But as you say, they are worried that transmitters might interfere with it. That being said, if you find interferance and you get a QSO going on that freq, you can drive them away. It worked on the leaky cable systems.

 

I am in a Lets-wait-and-see mode. I am not against new technology, if it works without causing other problems.

 

Mike. Desert_Warrior (aka KD9KC).

El Paso, Texas.

 

Citizens of this land may own guns. Not to threaten their neighbors, but to ensure themselves of liberty and freedom.

 

They are not assault weapons anymore... they are HOMELAND DEFENSE WEAPONS!

Share this post


Link to post

I'm in complete agreement with you, Mike. We can't be afraid of progress. Just curious, though, being fairly new to Amateur Radio. Could you expound on your comment about driving away the leaky cable systems?

 

-----

~ Boyd

N5CTI

 

"Never ask a man where he's from. If he's from Texas, he'll tell ya soon enough. If he ain't, don't embarrass him."

Share this post


Link to post

It was simple really. 20 or so years ago most cable systems were very much the same. Cable channel E was HBO. It was also on the 2m band.

 

If the cable system was REALLY a closed system, no leaks, it didn't matter. But if you could hear it, the system had a leak. With a sensitive radio, it doesn't take much of a leak to block your receiver. Now remember, the cable system carries micro-watts of power. Far far less power than a good 2m radio.

 

So we would complain to the cable company. And they blew us off. What could a few stupid hobbiests know about a technical thing like cable TV. They didn't fix anything. It was a closed system, it couldn't possibly be leaking.

 

LET THE GAME BEGIN.

 

It became a game. Drive around the city and look for a leak. When you find one, park near it, and start a QSO with someone on that frequency. Remember the micro-watts leakage? Imagine what WATTS of energy leaking IN did to the HBO programming! And if the leak was so bad we couldn't hear on that channel, we would go duplex and still have the QSO. We knew it was effective, because other hams would monitor the interferance and report how we were doing.

 

Cable users started to complain. The cable company complained to the hams. Know what we told them? It was a closed system, we couldn't possibly be leaking in. But if they were having problems, they were most welcome to notify the FCC.

 

To make a long story short....

 

It wasn't overnight, but quickly enough the leaks were fixed. To this day, you can see cable trucks with antennas (2m dipoles) on them cruising the city looking for leaks before we find them. It was fun while it lasted.

 

Could it be that 20 years later we are faced with the same event? Dunno. But history DOES repeat itself!

 

I am not worried!

 

Mike. Desert_Warrior (aka KD9KC).

El Paso, Texas.

 

Citizens of this land may own guns. Not to threaten their neighbors, but to ensure themselves of liberty and freedom.

 

They are not assault weapons anymore... they are HOMELAND DEFENSE WEAPONS!

Share this post


Link to post

Thanks for the history lesson, Mike.

 

-----

~ Boyd

N5CTI

 

"Never ask a man where he's from. If he's from Texas, he'll tell ya soon enough. If he ain't, don't embarrass him."

Share this post


Link to post

quote:
Originally posted by El Oso - N5CTI:

The impression I've gotten is that the current "control" usage of PLC is at a much lower frequency than the broadband version of it is expected to be. This makes sense, since Internet access would involve pushing grunches more data over the lines. Also, the potential for Amateur Radio to interfere with PLC was the rationale the FCC gave for denying the ARRL's request to add the 136 KHz band.


 

Two interesting topics.

 

We currently use our transmission lines to data link control signals to substations, link data and telemetry from power stations, link voice communications around our system, and link what amounts to intranet data around our system. And, as I mentioned, we have a pilot program running where we already lease data capacity to some companies and cities.

 

We have had a couple of instances of interference between our own equipment, but I don't recall any issues of interference with anyone else.

 

The PLC signals are set up as complementary signals on adjacent conductors. This both reduces their susceptability to RFI, and the likelihood they will cause RFI.

 

There is a potential for causing interference, but that is true of anything. I think all the current hysteria is a bit over the top. If the equipment is installed and maintained properly there should be no interferences.

 

As for the 136KHz issue, there is a possibility of interference with existing usage on power line control signals by 136KHz signals. It was a matter of weighing a recreational use against the potential to trip the power grid. The likelihood of problems was very low, but any disruption of the grid is very expensive and can have disastrous effects on some equipment. This was one of those conservative decisions weighted in favor of the more important system.

 

I suspect the issue of POSSIBLE (but not likely) future interference to ham radio will not have much effect on the approval of PLC. I expect that the FCC will approve PLC and tell hams to work out any RFI using existing mechanisms.

 

I don't think the sky will fall when PLC is approved for widespread use. There may be an RFI issue here and there, but nothing like the interference we accept from other sources.

 

Dave_W6DPS

 

My two cents worth, refunds available on request. (US funds only)

Share this post


Link to post

I really appreciate you guys who are more familiar with this sharing your viewpoints.

 

The conundrum for me is that people whose opinions I've learned to respect over the past several months have diametrically opposite positions. Ed Hare of the ARRL has been spending a lot of time researching the engineering aspect of BPL/PLC, and I can't dismiss his concerns out of hand. I don't know how familiar you guys are with his statements, but can either of you discuss where you think he's going wrong and his concerns are misplaced? Such as his concern about the placement of paired transmission lines actually serving as an antenna (driven element and reflector, if I understand him correctly).

 

-----

~ Boyd

N5CTI

 

"Never ask a man where he's from. If he's from Texas, he'll tell ya soon enough. If he ain't, don't embarrass him."

Share this post


Link to post

quote:
Originally posted by El Oso - N5CTI:

I really appreciate you guys who are more familiar with this sharing your viewpoints.

 

Ed Hare of the ARRL has been spending a lot of time researching the engineering aspect of BPL/PLC, and I can't dismiss his concerns out of hand.


 

Nor do I. I have the highest respect for Ed. In fact, I just sent him an E-mail copy of a letter my son sent from Iraq. We go back to Gulf War - I, when Ed sent me an antenna manual and a box of bubble gum. He has become a personal friend over the years.

 

Ed is splitting hairs. No pun intended. He is searching for the worst case possibility. As W1RFI, he will eventually get the complaints. The majority of us will not see that level of interference. Because of that, we are less concerned. And we are relying on Ed, who is much better equipped, to discover the real problems, and the fixes. That is his job. And I know he will do it well.

 

The antenna idea is accurate. But it reminds me of a story.

 

"If an unlimited number of cowboys with an unlimited number of shotguns shoot an unlimited number of shotgun shells into an unlimited number of road signs, they will eventually copy the works of Shakespeare in Braille".

 

The point is, there will be problems. But maybe not as many as you might think. And Ed, the FCC, and the offending power company, will find a solution. Remember my previous statement. If it leaks out, something can also leak in. And it is in the best interest of the offending company to keep it a closed system, for both sides.

 

Imagine how fast a power company would fix a noisy pole if your signal could disrupt the flow of power!

 

Mike. Desert_Warrior (aka KD9KC).

El Paso, Texas.

 

Citizens of this land may own guns. Not to threaten their neighbors, but to ensure themselves of liberty and freedom.

 

They are not assault weapons anymore... they are HOMELAND DEFENSE WEAPONS!

Share this post


Link to post

quote:
Originally posted by El Oso - N5CTI:

The conundrum for me is that people whose opinions I've learned to respect over the past several months have diametrically opposite positions.

-----

~ Boyd

N5CTI


 

It isn't so much being diametrically opposed--it is a matter of perspective.

 

Mr Hare is using the worst case scenarios to try to influence regulations.

 

Mike and I are looking at it from a more "real-world" perspective.

 

The worst case scenario rarely happens. There is a potential for interference, and if it happens there are mechanisms to fix it.

 

It is in the best interest of the power companies and the users of the new system to ensure they are properly designed and working well. Any specific problems will be identified and corrected, sooner or later.

 

Mike is right--a way for noise to get out is also a way for noise to get in. If there are noise holes, they will be plugged. Maybe not instantly, maybe not without a lot of discussion, but it will happen.

 

Some people think the glass is half full--others think it is half empty. A good technician realizes that it is simply twice as big as it needs to be!!!

 

Dave_W6DPS

 

My two cents worth, refunds available on request. (US funds only)

Share this post


Link to post

Thanks for the feedback, guys.

 

I've always been a bit skeptical of the "The Sky Is Falling!!!!" reaction to BPL. I can only hope that a reasonable compromise can be reached, since BPL seems to be a very good way to provide broadband Internet access to virtually everyone, as long as we don't "obliterate the HF spectrum." I suppose I'll join you in the "Wait and See" corner.

 

-----

~ Boyd

N5CTI

 

"Never ask a man where he's from. If he's from Texas, he'll tell ya soon enough. If he ain't, don't embarrass him."

Share this post


Link to post

quote:
Originally posted by El Oso - N5CTI:

Thanks for the feedback, guys.

 

I've always been a bit skeptical of the "The Sky Is Falling!!!!" reaction to BPL. I can only hope that a reasonable compromise can be reached,


 

Now, who said anything about compromise? How do you compromise on a LAW?

 

We (hams) are a service LICENSED to broadcast a signal. The cable systems (whichever) is a closed system, NOT LICENSED to broadcast a signal outside the cables. The FCC comes down HARD on leaky systems. All you need to do is report it.

 

It will work, or it will be so full of interference they will never get it to work. Like the cable system, if it leaks, they will be required to clean it up. If they don't they will have throughput problems as the interference kills them. And once reported, they have a specific time limit to clean it up or shut it down.

 

If it doesn't leak, then we will never know it is there, so who cares? If there is trouble, it won't last long.

 

icon_biggrin.gif

 

Mike. Desert_Warrior (aka KD9KC).

El Paso, Texas.

 

Citizens of this land may own guns. Not to threaten their neighbors, but to ensure themselves of liberty and freedom.

 

They are not assault weapons anymore... they are HOMELAND DEFENSE WEAPONS!

Share this post


Link to post

That's pretty much what I meant by compromise, although that's an awful choice of words. Specifically, I hope that the FCC doesn't "immunize" BPL from RFI with licensed services. THAT is where our greatest danger lies, IMHO.

 

-----

~ Boyd

N5CTI

 

"Never ask a man where he's from. If he's from Texas, he'll tell ya soon enough. If he ain't, don't embarrass him."

Share this post


Link to post

No way would the FCC cave in to big business to the detriment of the little guy! Oh, eh...nevermind.

 

Hehehe

 

Cadence

(OddTodd and CheleBell)

FRS2,12GMRS22(WPXD965)

Share this post


Link to post

quote:
Originally posted by El Oso - N5CTI:

That's pretty much what I meant by compromise, although that's an awful choice of words. Specifically, I hope that the FCC doesn't "immunize" BPL from RFI with licensed services. THAT is where our greatest danger lies, IMHO.

 


 

There's a 427 page document from the UK Radiocommunications Agency on the Compatability of VDSL & PLT with Radio Services in the Range 1.6MHz to 30MHz at UK RA Final Report

 

There's also a load of stuff, although you will need to go to the bottom of the page for the link to PLT, at RSGB website

 

At a recent open meeting in Leeds, the RSGB said (probably because the RA representatives were not allowed to make such comments) that technically a case could be made to oppose PLC, but that politically the UK Government were keen to allow it.

 

I don't know what your FCC oppinion might be, but we are talking about politicians making the decission, not decissions made on technical facts...

 

--... ...--

Morseman

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  
Followers 0

×
×
  • Create New...