dslreports logo
 story category
BPL Vs. Hams
The debate continues...
The Wall Street Journal explores the battle between ham radio fans and supporters of broadband over power-line (BPL) technology. The journalist goes for a ride with one enthusiast through Briarcliff Manor, New York, outfitted with a ham radio mounted to the dashboard - listening in on ham conversations. "As the car turned onto North State Road in the village of Briarcliff Manor in Westchester County, the voices faded, replaced with whirs and wahs -- what could have been sound effects from a 1950s science-fiction movie. The source, according to Mr. Lindquist, was right outside the window: the power lines running alongside the road."
view:
topics flat nest 

Matt3
All noise, no signal.
Premium Member
join:2003-07-20
Jamestown, NC

Matt3

Premium Member

I wonder....

Have any of the HAMS been to the trials going on in the Raleigh, NC area?

Karl Bode
News Guy
join:2000-03-02

Karl Bode

News Guy

Re: I wonder....

Yes, Progress Energy and Amperion have actually been cooperative, working with hams and ARRL to test the system.

»Quieting the Buzz

K McAleavey
Premium Member
join:2003-11-12
Voorheesville, NY

K McAleavey

Premium Member

Dirty signals

When DSL first came out, it was an anathema for 160 and 80 meter reception, as well as "dirt" all the way up to 6 meters. I can understand the concern. At least PHONE LINES are twisted pair, so there's some electromagnetic cancellation of the harmonics if the lines are properly balanced. The TRICK is for the power companies to get their RF carriers up to a high enough frequency that any potential interference won't hit the ham bands or other critical communication bands. The potential PROBLEM is that power lines are NOT twisted pair where cancellation of the offending radiated signals isn't possible.

But I remember what a mess early DSL was - folks near lines carrying DSL had NO hope of AM radio. Then came Rush Limbaugh and nobody really cared anymore.
contsole
Premium Member
join:2003-12-30
Newington, CT

contsole

Premium Member

Re: Dirty signals

------------------------------------------
"At least PHONE LINES are twisted pair, so there's some electromagnetic cancellation of the harmonics if the lines are properly balanced."
------------------------------------------

Ironically, my phone line's 200' trip up my driveway is NON-twisted pair (looks like zip cord, heavy solid copper conductors) and the utility line IS twisted ...but I realize we're talking about the lines on the streets.
KB2PSM
join:2002-08-06
Long Beach, NY

KB2PSM

Member

Re: Dirty signals

I suspect that the power line is probably not twisted, but probably twisted around a line used to support the AC wires from the pole to your house.
bonnyman
join:2003-04-16
Rome, GA

bonnyman

Member

Re: Dirty signals (drop cable trivia)

I suspect that the power line is probably not twisted, but probably twisted around a line used to support the AC wires from the pole to your house.

Utility drops from the transformer to the home often have insulated conductors stranded around a bare, grounded messenger/neutral. This affords a measure of safety -- should the insulation fail, the line shorts straight to the bare neutral and on to ground via the utility's grounding system. Such arrangments also get special treatment under the National Electrical safety Code.

This is not done for communications reasons.

As for the telephone drop cable that looks like zip cord, that may be a self-supporting drop cable. Underneath the jacketing, one side of the zip cord-looking cable may contain a steel messenger, the other a twisted pair.
Nighttime5
join:2001-11-30

Nighttime5 to contsole

Member

to contsole
That and any harmonic generated by poor connectors. So your band all belong to us! Not just the 2 to 80 mhz!

xNPC
As Usual, Have Nice Day
Premium Member
join:2000-11-08
Errington, BC

xNPC

Premium Member

Re: Dirty signals

hahah someone set up us the bomb.

Radio Active
My pappy's a pistol
Premium Member
join:2003-01-31
Fullerton, CA

Radio Active to K McAleavey

Premium Member

to K McAleavey
said by K McAleavey:
The TRICK is for the power companies to get their RF carriers up to a high enough frequency that any potential interference won't hit the ham bands or other critical communication bands.

I respectfully submit that the TRICK is more than that... Getting RF carriers to a "high enough frequency" is never going to work... The trick is to get power companies to not interfere with ANY licensed service, emergency or otherwise.

All RF communication channels between 2 and 80 MHz are at risk here, as well as whatever spectrum that will be affected by "sum and difference" products. These are unpredictable, and will be next to impossible to mitigate, IMHO.
Tuvok9
Rangcor The Great
Premium Member
join:2004-03-04
Fairview Heights, IL

Tuvok9

Premium Member

HAM Radios and Power line Broadband

Ham radio operations have been using a wireless frequency to communicate with other operators. but since the onset of Broadband more people are using it and now dsl over the power lines is available the Ham operators do not want it to continue because more people will flock to the broadband. leaving less operators for ham radios.
kruser
Premium Member
join:2002-06-01
Eastern MO

kruser

Premium Member

Re: HAM Radios and Power line Broadband

That's the stupidist thing I've heard yet today.
Ham's need to communicate with many people in areas that broadband does not even exist. Like disaster areas.

So if BPL is causing interference then these communications won't be able to take place.

K McAleavey
Premium Member
join:2003-11-12
Voorheesville, NY

K McAleavey

Premium Member

Re: HAM Radios and Power line Broadband

MUST concur here - been decades since I went for "ONE way radio" myself (former broadcaster, forgive me) ... but as a former active HAM, there's no greater joy beyond getting that "worked all countries" certificate from ARRL than being able to "key up" because there's a hole in the chatter that YOU can actually say something. One of my GREATEST joys as a kid was working Barry Goldwater in the middle of the night and carrying on meaningful conversations with him. And back in the 1960's, getting the opportunity to light up the final was a RARE one indeed.

Somehow, I don't think hams miss the idle banter that passes for "conversation" on the internet. Heh. "Quality, not quantity." My FCC First Class supercedes. 73's DE
WA2SVJ, calling CQ ... and BUGGER the utilities - Collins finals can backfeed the grid. (grin)
gurugordon
join:2004-03-24
Sunbury, PA

gurugordon to Tuvok9

Member

to Tuvok9
said by Rangcor:
Ham radio operations have been using a wireless frequency to communicate with other operators. but since the onset of Broadband more people are using it and now dsl over the power lines is available the Ham operators do not want it to continue because more people will flock to the broadband. leaving less operators for ham radios.

What a ludicrous statement to make. All you have done is expose your total ignorance about Amateur Radio. However, that is not even the issue here. The WSJ has done its readers a grave disservice with this piece, sidetracking the major issues in the process. Concerns about BPL are not only being expressed by Hams. FEMA, NTIA, Civil Aviation, Broadcasters, among others, have all stated their reservations about the threats posed to the HF radio spectrum by this system, and its undoubted potential to threaten life, homeland security and property by blanking out critical communications.

The questions that should have been asked are the ones mentioned by Forbes - the untried technology, the politics behind the FCC decision to jump shamelessly into bed with BPL, the limited potential in a market place already filled with established and successful alternatives, the lukewarm enthusiasm of power companies who have already suffered from burnt fingers following a previous failed attempt to embrace Internet technology, and last but by no means least, the distinct possibility of a lousy ROI.

rf_engineer
join:2003-08-04
USA

rf_engineer

Member

Re: HAM Radios and Power line Broadband

said by gurugordon:

The WSJ has done its readers a grave disservice with this piece, sidetracking the major issues in the process. Concerns about BPL are not only being expressed by Hams. FEMA, NTIA, Civil Aviation, Broadcasters, among others, have all stated their reservations about the threats posed to the HF radio spectrum by this system, and its undoubted potential to threaten life, homeland security and property by blanking out critical communications.

I'll say the WSJ really messed up. You think they would have dug deeper and explored the business model and found its shortcomings, especially in rural areas. The FCC and proponents claiming the interference problem is solved, but a quick car ride with equipment shows otherwise. Digging deeper, the implications of allowing a radiating broadband network with was is arguably outdated Part 15 regulations. And, as you mention, the public safety communications issues raised. A clever piece could have tied this in to the 800Mhz interference FCC debacle. But instead the focus became Amateur Radio stereotypes....or is that what investors base their decisions on these days ?
rf_engineer

rf_engineer to Tuvok9

Member

to Tuvok9
said by Tuvok9:
Ham radio operations have been using a wireless frequency to communicate with other operators. but since the onset of Broadband more people are using it and now dsl over the power lines is available the Ham operators do not want it to continue because more people will flock to the broadband. leaving less operators for ham radios.

Wow, this is really out there. Considering hams are more tech oriented that most people, it's likely that there's a higher percentage of hams with broadband access than the general public. The Internet in general has enhanced ham radio through discussions, websites, and the development and exchange of ham radio related software and material. The Internet also is a key enabler of new technologies like software defined radios. As President of our local Amateur Radio club, I've got more potential hams through websites and email than any other means.

If Ham Radio was truly against broadband, we would have stopped DSL, Wireless Broadband, and Cable but you won't find any opposition from us. It's the interference from BPL we oppose, not broadband. Come up with an interference-free BPL and we're on board. Unfortunately that's impossible with the HF BPL that we're talking about.

There is an alternative microwave high speed BPL that doesn't have the interference issues, but the FCC has apparently ignored it and it's likely that investors in the doomed HF BPL technology aren't too happy about it. Despite the evidence against BPL and the public outcry, the FCC continues to march on with broadband fool's gold destined to pollute the airwaves and destroy uniquely capable wireless spectrum with a wired network. If the FCC was caretaker of the Sistine Chapel, they'd be painting the ceiling with purple colored latex paint right now because it would brighten up the place and street vendors said it would look nice.
netscape 6
join:2002-03-07
Constantine, MI

netscape 6

Member

Re: HAM Radios and Power line Broadband

said by rf_engineer:


If Ham Radio was truly against broadband, we would have stopped DSL, Wireless Broadband, and Cable

How would you have done that?

rf_engineer
join:2003-08-04
USA

rf_engineer

Member

Re: HAM Radios and Power line Broadband

said by netscape 6:
said by rf_engineer:


If Ham Radio was truly against broadband, we would have stopped DSL, Wireless Broadband, and Cable

How would you have done that?

"Stopped" was probably a bad choice of words. "Opposed" is what I meant. Understand the underlying theme, though -- Amateurs aren't against BPL as the title of the forum suggests or the original poster claims.. We're against interference and pollution of the radio spectrum. Claims that we're against broadband are just wrong, and I challenge the original poster to find any evidence to the contrary.

Admittedly, Amateur Radio isn't going to stop BPL. I think competition, a weak business model, and carriers frustrated with interference complaints and struggles to find less interference prone spectrum will kill BPL eventually. This won't happen, though, until after several years of pain for licensed radio services and millions of dollars have been spent on BPL systems. Investing in BPL goes beyond the normal business risk associated with cutting-edge high tech investing. BPL vendors have been trying to get BPL to fly for six years. The evidence against BPL is overwhelming, and the "canary in the mine" is withering.
Trivista
join:2003-11-11
Longview, TX

Trivista to netscape 6

Member

to netscape 6
The same way they damn near destroyed the hobby. By over-regulating it.

If the HAMS had not been so 'picky' about who could get a HAM license (code requirements, etc) their would be a lot more people who where HAMS now and they would have a lot more political clout. But they changed their regs too late and as a result they have been losing political clout due to the falling number of people in the hobby.

tenbase
join:2000-07-19
Alexandria, VA

1 edit

tenbase

Member

Re: HAM Radios and Power line Broadband

Er, the code requirement was an international law. Hams do not set the standards for licensing, the FCC does.

Also, there are more hams today than ever before. Not only that but the barriers for entry have never been lower. This is not a new thing.
Rusty_Sklfrd
join:2004-03-24
Ormond Beach, FL

Rusty_Sklfrd to Tuvok9

Member

to Tuvok9
Ham radio operations have been using a wireless frequency to communicate with other operators. but since the onset of Broadband more people are using it and now dsl over the power lines is available the Ham operators do not want it to continue because more people will flock to the broadband. leaving less operators for ham radios.
That comment was spoken in pure ignorance. The Amateur Radio community makes use of broadband internet services as much as anyone else does. In addition to the usual email/bulletin postings, DX Spotting activities, etc, ham operators world wide are linking VHF/UHF repeaters and simplex gateways through VOIP networks which absolutely requires a solid broadband internet backbone. There are also remoted HF stations that hams utilize 24 hours a day which also require broadband internet service.

BPL has been banned in various countries around the world because of the interference issue, federal US agencies have made official comments to the FCC that BPL will cause irreperable harm to emergency communications, etc etc. What more has to be said!? Until such time that the utility companies fix the service so it doesn't intentionally interfere (sorry, I don't buy that it is merely violating existing unintentional interference regs, they know it interferes - it is no longer a question) with a broad cross section of the HF spectrum it should be stopped.
w2co
join:2003-07-16
Longmont, CO

w2co to Tuvok9

Member

to Tuvok9
This is an all time new one! DSL over the power lines?
These are the types who believe all that the BPL companies tell them, and know absolutely nothing about anything to do with it, and then they will even make comments openly publishing their complete incompetence. I think there are people like this in the FCC too...

ifarrell
join:2000-08-10
Willow Spring, NC

1 edit

ifarrell to Tuvok9

Member

to Tuvok9
said by Tuvok9:
Ham radio operations have been using a wireless frequency to communicate with other operators. but since the onset of Broadband more people are using it and now dsl over the power lines is available the Ham operators do not want it to continue because more people will flock to the broadband. leaving less operators for ham radios.

Are you on drugs?????
That's the stupidest bass ackwards statement ever made on this forum IMHO.

rf_engineer
join:2003-08-04
USA

rf_engineer

Member

Re: HAM Radios and Power line Broadband

said by ifarrell:
said by Tuvok9:
leaving less operators for ham radios.

Are you on drugs?????
That's the stupidest bass ackwards statement ever made on this forum IMHO.

Hey, let's not forget some of the other past off-the-wall forum suggestions and comments:

- A national "off switch" for BPL to use during disasters
- When the power goes out, so will the interference so you have nothing to worry about
- Why do you need ham radio when there's Internet audio streaming
- Angry teenagers will vandalize ham stations when their broadband goes down
- I never heard anyone on the air, so ham radio must be dead
- Everyone is on satellites now
- Cell phones can blah blah blah
- We can light up every outlet with Internet !

Oh wait, strike that last wacky comment, that was made by the FCC, not people in this forum :-D
Tuvok9
Rangcor The Great
Premium Member
join:2004-03-04
Fairview Heights, IL

Tuvok9 to ifarrell

Premium Member

to ifarrell
said by ifarrell:
said by Tuvok9:
Ham radio operations have been using a wireless frequency to communicate with other operators. but since the onset of Broadband more people are using it and now dsl over the power lines is available the Ham operators do not want it to continue because more people will flock to the broadband. leaving less operators for ham radios.

Are you on drugs?????
That's the stupidest bass ackwards statement ever made on this forum IMHO.

Are you a Ham radio operator?

CheeseWare
Premium Member
join:2003-04-24
Burnaby, BC

CheeseWare

Premium Member

BPL -Vs- ROIs

I would refer BBR BPL news coverage and its readers to the Forbes story that did not sidetrack on irrelevant matters and focused on the main issue of questionable ROI.
»www.forbes.com/business/ ··· 349.html
jacour
Premium Member
join:2001-12-11
Matthews, NC

jacour

Premium Member

Re: BPL -Vs- ROIs

BPL is a clearly inferior technology when compared with DSL and Cable, due to lower speeds and the interference issues. I honestly don't see how it will be economical to compete with the established providers in urban areas where the cable / telco infrastructure already exists. The current DSL price wars are ample evidence that the telcos are not going to wave the white flag.

BPL does hold some promise for rural areas that are arguably underserved by cable and too far from the POP for DSL to be feasible, but unless BPL can be deployed inexpensively are there enough consumers to justify the required capital expenditures? Are any of the trials taking place in rural communities? I suspect the weight of economics will kill the technology.

Radio Active
My pappy's a pistol
Premium Member
join:2003-01-31
Fullerton, CA

Radio Active

Premium Member

Re: BPL -Vs- ROIs

said by jacour:
BPL does hold some promise for rural areas that are arguably underserved by cable and too far from the POP for DSL to be feasible, but unless BPL can be deployed inexpensively are there enough consumers to justify the required capital expenditures? Are any of the trials taking place in rural communities? I suspect the weight of economics will kill the technology.

That is just one thing that BPL providers are keeping as their "dirty little secret"... The cost of equipment (repeaters, bridges, amps, etc...) far outstrips that of provisioning lines for DSL as well as the profit margin they must maintain to make BPL profitable. To make a powerline BPL ready will cost SO much money that the rural areas with a population density that is insufficient to support the investment will never see BPL anyway... So where is the validity of the "bringing broadband to the rural areas" aspect of BPL?

I think you are right about the economics. Upon even cursory examination of BPL in terms of promises made, the technology doesn't even seem able to hold itself up.

Remington7
join:2000-09-29
North Vernon, IN

Remington7

Member

Another BPL going live

»www.cinergy.com/News/def ··· s_id=420

They are supposed to be expanding their area now that the testing is over. Can't remember where I read it but they were offering 1M up and down for 19.99 and 2M for 29.00 and 3M for 39.99.

Transmaster
Don't Blame Me I Voted For Bill and Opus
join:2001-06-20
Cheyenne, WY

1 recommendation

Transmaster

Member

Big problem

There is one problem that I have not seen discussed anywhere. I have friends who are engineers for Qwest and they are very worried about the BPL technology. Their testing indicates BPL will interfere with their DSL lines if BPL share the same poles. The FCC can screw over type 96 stake holders all they want but if SBC, Verizon, Qwest, etc start having trouble with BPL impacting their customers the
lawyers will have a field day.

I wonder how many houses will burn down because some idiot
tries to plug his modem directly into a wall outlet. Think stupidity like this doesn't exists. I and many others on a 2 meter repeater listened while a pair of mono-brain cell types where complaining they couldn't get window's 95 to work on their computer. Turns out they where trying to load 95 into an Apple computer. There where a number of us who almost wrecked our cars.
jdir
join:2001-05-04
Santa Clara, CA

jdir

Member

Re: Big problem

QWest, Comcast and all baby bell are sure worried. It's a cheaper high speed alternative network for the consumer.

House will not burn down due to modem plugin. It's like saying buying a hair dryer will cause more death because people don't know how to use it in the bathroom. Plus BPL modem probably just have those three prong plug and RJ-45 for ethernet. Just simply plug into the wall socket.

Maybe it is time for the FCC to allocate or give a frequency band for BPL. I can hear all the Ham crying foul over that. Maybe time for Ham gear to use spread spectrum scheme so more Ham can use the shrinking air wave.

CheeseWare
Premium Member
join:2003-04-24
Burnaby, BC

1 edit

CheeseWare

Premium Member

Re: Big problem

"It's a cheaper high speed alternative network for the consumer."

Where did you come up with this? I am not a ham and I am crying foul over giving friends special rights over spectrum. If they are going to free up some spectrum, let people bid for them. Not just the FCC BPL friends because they have invested so much political capital into this and pretend to not understand the difference in between the home and access segments.

BTW, do you not have lots of silly litigation issues with your lawyers? Do you really expect this to change with BPL?
And what if BPL interferes with DSL at the pole as mentionned by Transmasters?

Leave the hams alone if you really wish to progress on this. They are really not the ones hindering broadband deployment. Solve the ROI and target market where BPL fits in and you will get my support. I am still looking for one.

Transmaster
Don't Blame Me I Voted For Bill and Opus
join:2001-06-20
Cheyenne, WY

Transmaster to jdir

Member

to jdir
said by jdir:
QWest, Comcast and all baby bell are sure worried. It's a cheaper high speed alternative network for the consumer.
This isn't true for Qwest their technical people don't think BPL stands a chance of competing with them. The phone companies already have most of the infrastructure in place and the trained technicians to service it. BPL has very little except power lines with few technicians trained to service BPL equipment. The only concern Qwest has is with the BPL trash getting into their network. Qwest looks upon Cable as their real competition and this is who they are going after.

richk_1957
If ..Then..Else
Premium Member
join:2001-04-11
Minas Tirith

richk_1957 to Transmaster

Premium Member

to Transmaster
I never thought about that:(
It will probably wipe out (for all practical purposes) anything sharing the pole except cable, which by it's nature is shielded
w2co
join:2003-07-16
Longmont, CO

w2co

Member

Re: Big problem

The cable CO's distribution amplifiers are powered from those same lines. See my post on "conducted" noise.
w2co

w2co to Transmaster

Member

to Transmaster
"Their testing indicates BPL will interfere with their DSL lines if BPL share the same poles."

This is because of the direct connection to the power lines to power their equipment. You know the videos and stories about driving along a street with an hf radio in the car and hearing all those wurring noises at S9+10-15db over, that is the "radiated" noise levels of BPL at work. Well guess what, anything directly plugged into the power outlets will receive ten fold this power level of noise, this is called "conducted" noise. That's why I have often said that all those baby monitors, garage door openers, cordless phones, TV's on ch 2-31 with rabbit ears, etc. will become degraded if not useless. Things like this are never told to the public, especially when they're trying so hard to sneak this crap into this country. Hams are not the only "licensed" users of this spectrum, what about the NTIA with homeland security equipment that we tax payers have already dumped millions of dollars into? It will surely be degraded as well. May have something to do with terrorism?
Nighttime5
join:2001-11-30

1 edit

Nighttime5

Member

The answer to this!

Ok let let the power companies do this! Bet you all are saying. Is he nuts?

BUT they must work from the most rual areas torward the cities. Anyone on their "Grid" must be abble to get it no matter where they are. Even if 100 miles plus from any city. Ups some mountain or vally. If they feed power that user must be abble to use it at a decent bandwidth and speed. Even in Parump NV! In less than one year they will drop this quck! Esp when their board and stock holders see the cost per revenue return on this.

If you cant convince some one just get a bigger stick!

bolt
End of the line DSL sucks.
Premium Member
join:2003-11-11
Charlestown, IN

bolt

Premium Member

Re: The answer to this!

quote:
BUT they must work from the most rual areas torward the cities. Anyone on their "Grid" must be abble to get it no matter where they are. Even if 100 miles plus from any city. Ups some mountain or vally. If they feed power that user must be abble to use it at a decent bandwidth and speed. Even in Parump NV!
Fine. Lets get the telcos and cable companies set up this way too. If this were the case, broadband would be available almost anywhere in the country
8744675
join:2000-10-10
Decatur, GA

8744675

Member

Turnabout is fair play

I recall that for years, as a youngster, my family's favorite TV programs were constantly interrupted by ham radio interference coming through the TV set. "CQ, CQ this is station WXYZ, come in, over" always blasting through the set in the middle of the show. It was a common fact of life for anyone who lived near a ham operator.

After numerous complaints, a couple nearby operators were required by the FCC to come and put filters on our TV sets, to no avail.

I guess turnabout is fair play, just 40 years too late.

rf_engineer
join:2003-08-04
USA

rf_engineer

Member

Re: Turnabout is fair play

said by 8744675:
I recall that for years, as a youngster, my family's favorite TV programs were constantly interrupted by ham radio interference coming through the TV set. "CQ, CQ this is station WXYZ, come in, over" always blasting through the set in the middle of the show. It was a common fact of life for anyone who lived near a ham operator.

After numerous complaints, a couple nearby operators were required by the FCC to come and put filters on our TV sets, to no avail.

I guess turnabout is fair play, just 40 years too late.

Actually, the FCC would never mandate an Amateur to fix an interference issue with a TV set. However it is strongly recommended and encouraged as general good practice that all Amateurs work with their neighbors to cure interference issues.

Unfortunately, a lot of consumer electronics are not properly designed and have interference reception problems. This could be easily cured with the addition of a couple dollars worth of components, but many manufacturers skimp and don't include the parts and the consumer is left holding the bag.

I know several Amateurs that operate at legal limit power levels with no interference problems to their neighbors. Turnabout may be fair play in your book, but does it make sense to decimate a service that provides community service, pioneered many of the communications techniques used today, and provides a training ground for tomorrow's engineers?

alex4life
Alex4life
Premium Member
join:2001-06-22
Delta, BC

alex4life

Premium Member

Bizarre

I didn't know HAM radio still existed!

I can't say that I've ever met anyone, or have heard of anyone who uses HAM radios in my entire life, other than on this site.

So what gives? How can HAM radio have such power and clout when it has never had any part in anything in my life? Who are these HAM operators? Where are they?

••••••••

whizkid3
MVM
join:2002-02-21
Queens, NY

whizkid3

MVM

twisted pairs, Hams & WiFi

quote:
At least PHONE LINES are twisted pair, so there's some electromagnetic cancellation of the harmonics if the lines are properly balanced.
Actually, no. Even if they are twisted, the twisted pairs themselves do absolutely nothing to prevent radiated signals, nor harmonics. When differential driver electronics are used on both ends of a twisted pair circuit, the recievers can eliminate a lot of noise ingress into the communications link, as the desired signals are opposite in polarity, while the noise on both wires of the pair is at the same polarity. The differential receivers reject same polarity signals (CMRR - common mode rejection ratio), while keeping the opposite polarity signals. The wires are twisted so that they remain very close together inside of the cable jacket.
quote:
The TRICK is for the power companies to get their RF carriers up to a high enough frequency that any potential interference won't hit the ham bands or other critical communication bands.
That would be quite a trick, considering that all bands from long-wave up to microwaves are used by some form of communication system; and power lines are physically unable to transmit microwave & higher signals. Basically, it's impossible.

I wish people would stop getting on the Amateur Radio enthusiasts (HAMs) for this. This has little to do with HAM radio, but everything to do with all radio. It just so happens that the HAMs are very technical astute, and willing to devote their time (for free) to fight this infeasable technology. This technology will degrade all radio communications, from emergency bands, aircraft bands, radar, your WiFi system, cell phones, etc - not just amateur radio bands.
gurugordon
join:2004-03-24
Sunbury, PA

gurugordon

Member

The Ham Perspective

This letter to the editor of the WSJ is reproduced by permission of the author.



March 26, 2004

Editor, The Wall Street Journal

Dear Sir:

Your front page article of March 23 "In This Power Play, High-Wire Act
Riles Ham-Radio Fans, New Use for Lines Sparks Tension With Operators"
reads like a press release from those utility companies who wish to
promote the questionable use of electric power lines for residential
broadband internet service. Your attempt to denigrate this nations
700,000 ham radio licensees and their primary membership organization,
the American Radio Relay League, is a pathetic piece of journalism and
demonstrates a complete lack of effort to research the opposing point
of view.

Your article portrays hams as an aging group holding on to an obsolete
technology of "dots and dashes" and shows an extreme ignorance of all
that modern ham radio has to offer. Today's hams are experimenting
with digital communications modes, software defined radios and other
cutting edge communications technologies. We have a far deeper and
richer mastery of electronics technology than 99 percent of the
computer programmers who inhabit the internet and who really have no
understanding of the underlying electronic technology that their
software runs on. Hams are also in general a nicer group of people
than the hackers, spammers, scam artists, virus writers and
pornographers who inhabit the internet.

Hams have built and launched more than 50 communications satellites
into Earth orbit, the first of these in 1961, six months before the
first commercial Telstar satellite. A subset of hams have mastered the
technology needed to bounce radio signals off of the moon. There was a
ham radio station onboard the Russian space station MIR and there is
currently one onboard the International Space Station. A significant
percentage of the US astronaut corps have ham licenses, including
three of the seven astronauts who died aboard the Space Shuttle
Columbia last year.

Amateur radio is not just a silly game. The contests and activities
that hams engage in do have a serious side, they serve as practice and
preparation for the day when emergency communications services will be
needed. A great many recent instances of natural and man made
disasters have shown the ability of amateur radio communications to
function when other systems fail. Cellular telephones and the internet
depend on heavy infrastructure investments that can be overloaded or
rendered
inoperative in a major emergency. Ham radio, by its simple nature, is
not dependent on complex and expensive infrastructure. Many cell phone
towers do not even have emergency battery backup anymore, as a cost
saving measure.

On September 11, 2001 the cell phone networks in New York and
Washington crashed under the strain of heavy use. Ham radio operators
were able to communicate. During last summers electrical blackout many
cell phone systems were out of commission. Hams maintained
communications during Hurricane Andrew and many other natural
disasters. Hams have had a formal relationship with FEMA, its Civil
Defense predecessors and the Red Cross for over 60 years.

Last year hams were extremely helpful to authorities in searching for
debris from the Space Shuttle Columbia in remote areas of Texas. Their
simple equipment could communicate in wilderness areas where more
sophisticated police communications systems would not function. During
the 1991 coup attempt in the Soviet Union, ham radio operators on the
ground kept the MIR cosmonauts apprised of the true situation in their
home country, when Soviet Mission Control would not tell them any news
because of political reasons. When Saddam Hussen's troops invaded
Kuwait, many of the news stories "smuggled out of Kuwait" were
transmitted by ham radio operators in that country. This was kept
secret at the time because hams worldwide were in fear for their
colleagues' lives under Iraqi military occupation. When the US
military invaded/liberated Grenada in 1983, our troops had to use
commercial telephone calling cards to make contact with the Pentagon,
while hams in Grenada kept the world informed. One ham's report was
carried live on ABC's "Nightline".

In spite of this rich history, your writer chooses to remain ignorant
of the facts and portrays us as a bunch of obsolete old fogies who
can't adjust to changing times.

Measurements of radio interference in locations where Broadband over
Power Lines (BPL) technology has been deployed clearly do show a
harmful level of radio interference. Measurements made by companies
with a financial stake in the deployment of BPL are far more suspect
than our own measurements are. Interference from BPL in residential
areas will affect not only licensed radio amateurs but also citizens
band radio operators and anybody who listens to international
shortwave broadcasts.

Your own article contradicts itself. The second and third paragraphs
clearly indicate that your reporter observed harmful radio
interference in an area served by BPL but then you go on to claim that
interference is no problem and the hams are just complaining for the
sake of making noise.

The fact that ARRL has raised $300,000 from 5,600 donors would
indicate an average donation of $53 per person. This grass roots
campaign is far more democratic than the much greater sum of money
that will be spent to purchase influence in Washington by the
companies who wish to promote their questionable technology.

We are not trying to stop the growth of the internet, but we ask that
it be done in a responsible manner. Cable modems, DSL service and
eventually fiber optic links can provide residential broadband service
in a socially responsible manner without trashing the radio spectrum.
I am sure that many products and services could be delivered to
consumers at lower cost if environmental and pollution controls were
lifted so that manufacturers could dump their waste products into the
nations lakes, rivers and air without restriction.

Allowing BPL companies to pollute the radio spectrum that is shared by
all citizens in the name of slightly cheaper internet service is not a
defensible position. We feel that the FCC, like many government
agencies today, has been co-opted by corporate interests and no longer
works for the best interests of the citizens of this country. In
contrast the communications authorities in Japan have decided not to
allow BPL technology to be used in their country.

Simple economic theory taught in many schools indicates that it is not
responsible behavior to shift costs to innocent third parties for the
benefit of one particular group. We wish to preserve the existence of
amateur radio in the 21st century so that it will be available to the
younger generation when they grow tired of playing games and writing
software on their computers and decide to seek out a real technical
challenge.

Daniel Schultz
Burtonsville, Maryland

FCC assigned call sign: N8FGV
E-mail: n8fgv@amsat.org