[TriLUG] Powerline - Ethernet over AC lines & Linux

[Neil L. Little]

Indications are that the infrastructure manufacturers and telecom 
companies have written off BPL.

The push now has consolidated toward using EVDO, 3G and emerging WiMAX 
technologies.
And thats a good thing!

Neil Little, WA4AZL
JARS Forever!!

James Brigman wrote:
> On Fri, 2007-09-21 at 21:55 -0400, Ron Joffe wrote:
>   
>> On Friday 21 September 2007 21:39, Neil L. Little wrote:
>>     
>>> Of course there is
>>> more to the story but basically  BPL is a bad idea.
>>>       
>> Sorry to be the dissenting view here, but it's not as much that BPL is a bad 
>> idea, but that there have been some bad implementations. If you were a rural 
>> farmer and wanted something faster then dial up, in many parts of the country 
>> you don't have much choice. If your local electric utility comes and offers 
>> you a choice, at what cost would you take it? 
>>     
>
> What do you mean by separating the idea of BPL from implementation? Can
> you cite any source quantifying demand for BPL?
>
> How can you say the farmer has no choice when HughesNet is available to
> anyone with an unobstructed south-southwest view? What about the current
> crop of cellphones (ie: Blackjack) which can function as a computer
> modem for the new 3G cell-based broadband network?
>
> The one person I have ever known who didn't have a broadband media
> internet alternative successfully used the Sprint network for RF
> networking. BPL was no more a reality for him than it would have been
> for your mythical farmer.
>
>   
>> Powerline carrier in itself works quite well, Many utility have (or are in the 
>> process of) implementing powerline carriers to read their electric meters. 
>> That's a situation where the technology is there, it does not interfere, and 
>> provides a very good solution. The situation comes when you try to increase 
>> the bandwidth to the point where the electric lines start radiating a 
>> significant amount, then you get nice radio spectrum interference. 
>>     
>
> Power line carrier does not work well and is not used to read electric
> meters. Please substantiate your claims by citing your sources. 
>
> Your own meter is not remotely read via power line carrier. If it is
> remotely read, it's via an RF system. Most successful residential meter
> reading systems communicate in the RF spectrum and are read from a
> central point or by a human in a truck. The meters in my neighborhood
> are read via RF. Progress Energy reads meters this way:
>
> http://www.comverge.com/news-events/news/07202005_01.cfm
>
> What does "works quite well" mean? Does less than 5 miles of usable
> transmission line with repeaters every 2000 feet mean "works quite
> well"? 
>
> Are you aware that at least one currently-available BPL system is an
> extreme bandwidth hog because the repeaters have to use separate chunks
> of the RF spectrum to read from one section to the next? 
>
> Are you aware that BPL runs on frequencies already in use by Amateur
> Radio, Public Service agencies and even FM radio and Television?
>
> Are you aware that BPL power levels are equivalent to that used in Ham
> Radio "QRP" devices, which can radiate around the world?
>
> Are you confusing BPL with X-10 devices?
>
> BPL does not promise the ability to plug into a bedroom power outlet and
> download your favorite pr0n. 
>
> The only viable lengths of power line to use are the points where the
> distribution lines branch off the higher-voltage transmission lines at
> the substation. Then at the curbside, they pull the signal off the line
> and route it to the house via other means. Progress Energy does not feed
> BPL directly to the house because the final step-down power transformer
> (the gray can on the pole or green box at the property line) cannot pass
> BPL signals in any usable manner. 
>
> As far as hams are concerned, BPL does not work well because power lines
> are excellent antennas in the frequency ranges used by BPL:
>
> http://www.cq-vhf.com/BPL.html
>
>   
>> The power levels are a direct result of cost to benefit ratios. Some system 
>> utilize rather low power, and many repeaters to achieve a BPL solution which 
>> does not interfere. Repeaters are expensive to install and maintain. So there 
>> are clean solutions, but at a higher cost. Finally it comes down to what the 
>> farmer in the rural area is willing (and able) to bear to catch up to the 
>> rest of us. 
>>     
>
> What cost benefit ratio determines BPL power levels? Can you explain
> what you mean by this?
>
> Please substantiate your claims of zero interference by citing your
> sources, preferably sources describing implemented BPL systems, not BPL-
> provider-propaganda. (which rules out anything published by George
> Spencer on the topic...)
>
> All BPL systems interfere, regardless of power level. The question is
> only "How Much?" The problem with BPL is that it would generate
> interference 24x7. 
>
> BPL differs from any other available internet supplying medium in that
> it is the first medium that specifically, expressly interferes with
> other radio services. NO OTHER MEDIUM has this disadvantage, not even 3G
> cell-tower-based service.
>
> Your farmer still has no bearing on your argument. He's probably surfing
> the 'net on an optical fiber line hosted on power poles or the power
> right-of-way, if he's not using satellite.
>
> It is this writer's sincere hope that the life will be crushed out of
> BPL by all other physical media alternatives. 
>
> JKB
>
>