Broadband Powerline Impact on Audio??

[Marty Troum]

In the February issue of Stereophile, I read a distressing article by
Jim Austin (page 19) regarding the FCC's support of Broadband Over
Powerline (BPL). It seems that the application of broadband
transmissions to the powerline structure of our communities and homes
will most likely impact our high-end audio equipment by introducing
harmful, high-level, high frequency noise into the AC supply. What,
if anything, is the audiophile community doing about this issue? Is
there any action I can take? Is it a real threat to us audiophiles?
Is there any data available? Also, are the power conditioning
companies preparing for this potential onslaught? I'd appreciate any
commentary or sources for more information. I have read extensively
on the internet regarding the concept, but I haven't found much
available from the audiophile perspective. Thanks for your responses.
Marty Troum

[Robert Morein]

"Marty Troum" > wrote in message
...
> In the February issue of Stereophile, I read a distressing article by
> Jim Austin (page 19) regarding the FCC's support of Broadband Over
> Powerline (BPL). It seems that the application of broadband
> transmissions to the powerline structure of our communities and homes
> will most likely impact our high-end audio equipment by introducing
> harmful, high-level, high frequency noise into the AC supply. What,
> if anything, is the audiophile community doing about this issue? Is
> there any action I can take? Is it a real threat to us audiophiles?
> Is there any data available? Also, are the power conditioning
> companies preparing for this potential onslaught? I'd appreciate any
> commentary or sources for more information. I have read extensively
> on the internet regarding the concept, but I haven't found much
> available from the audiophile perspective. Thanks for your responses.
> Marty Troum
>

Marty,
I wouldn't worry about it. It could be necessary to install a powerline
filter. There is nothing unique about this kind of noise.

[Arny Krueger]

"Marty Troum" > wrote in message


> In the February issue of Stereophile, I read a distressing article by
> Jim Austin (page 19) regarding the FCC's support of Broadband Over
> Powerline (BPL).

It's not the first powerline-based communications link around, and it
probably won't be the last.

> It seems that the application of broadband
> transmissions to the powerline structure of our communities and homes
> will most likely impact our high-end audio equipment by introducing
> harmful, high-level, high frequency noise into the AC supply.

AC power supplies are built to resist this sort of thing. However, I have to
admit that I spent some time thinking of how to build a high end amplifier
that would have minimal resistance to power line noise. Not surprisingly, I
came up with a rough approximation of a SET, zero loop feedback and all.

Seems like a great sales opportunity for the usual high end snake oil
suspects. Here's a step-by-step marketing plan:

(1) Pump the market full of as much badly-designed audio gear as possible.
SET power amps come to mind. Come up with off-the-wall justifications for
removing well-known and effective technological solutions to power line nose
from existing designs.

(2) Then, raise a big fuss about the "...likely impact our high-end audio
equipment by introducing harmful, high-level, high frequency noise into the
AC supply."

(3) Have well-known snake-oil technologists (John Curl and Richard Marsh's
names immediately come to mind) write articles in low-circulation magazines
and esoteric web sites about the most backward and left-handed means that
can be thought of to purportedly solve the *problem* of harmful, high-level,
high frequency noise in the AC supply. If a 50 cent part will do the job,
come up with off-the-wall justifications for using a $50 part. Phrases like
"high resolution" and "dielectric absorbtion" come to mind.

(4) Load up the market with a selection of signal line filters, power line
filters and powerline voltage regenerators to address the problem, which may
actually exist in some cases because the high end industry already did their
homework and packed the market with maximally-susceptible equipment in step
number 1.

(5) Re-engineer the origional bogus equipment designs that the market has
now expensively band-aided, and reap additional profits by replacing that
old equipment with equipment conforming to the newly-modified designs.



> What, if anything, is the audiophile community doing about this issue?

No doubt, they are getting rid to hock the family homestead to load up on
expensive non-solutions to non-problems. They've got a 20+ year history of
doing this (separate CD players and DACs, anybody?) so why should they stop
now. This is where the *true* excitement in audio comes from, after all.

> Is there any action I can take?

Rev up your plastic.

> Is it a real threat to us audiophiles?

It's a truely dire threat, and if you don't believe me check recent and
up-coming issues of your favorite high end ragazines, and web sites.

> Is there any data available?

Yes, people have been pumping AF, LF, MF, IF, RF, and goodness-knows-what
into power lines for years. Sometimes they actually tried to do this on
purpose, and other times they just did it by accident.

> Also, are the power conditioning
> companies preparing for this potential onslaught?

Smart investors are no-doubt buying their stock.

> I'd appreciate any commentary or sources for more information. I have
> read extensively
> on the internet regarding the concept, but I haven't found much
> available from the audiophile perspective. Thanks for your responses.

Of course this begs the question as to whether I'm really an audiophile, or
if instead I'm merely a sane mature adule with a modicum of common sense.

[John Atkinson]

Robert Morein wrote:
> "Marty Troum" > wrote in message
> ...
> > In the February issue of Stereophile, I read a distressing article
> > by Jim Austin (page 19) regarding the FCC's support of Broadband
> > Over Powerline (BPL). It seems that the application of broadband
> > transmissions to the powerline structure of our communities and
> > homes will most likely impact our high-end audio equipment by
> > introducing harmful, high-level, high frequency noise into the AC
> > supply...
>
> I wouldn't worry about it. It could be necessary to install a
> powerline filter. There is nothing unique about this kind of noise.

Ben Duncan in the UK has done some calculations to determine what
level of multi-MHz signal would be required to drive a typical
audio amplifier circuit into slew-rate limiting. I had expected this
to be in the region a few hundred millivolts; it turns out to be at
least an order of magnitude lower. Some products may well be in
trouble without some kind of protection.
John Atkinson
Editor, Stereophile

[Marty Troum]

Arny,
Although I understand your response and apparent aversion to "snake
oil" stuff, I am not sure that you answered my humbly-asked question.
Should I ignore the issue because it will NOT present a problem (in
your opinion) or should I be concerned? If you have only cynical
remarks to respond, please don't. I am merely an ignorant person in
search of some knowledge. Thanks.
Marty

On Sat, 22 Jan 2005 17:29:24 -0500, "Arny Krueger" >
wrote:

>"Marty Troum" > wrote in message

>
>> In the February issue of Stereophile, I read a distressing article by
>> Jim Austin (page 19) regarding the FCC's support of Broadband Over
>> Powerline (BPL).
>
>It's not the first powerline-based communications link around, and it
>probably won't be the last.
>
>> It seems that the application of broadband
>> transmissions to the powerline structure of our communities and homes
>> will most likely impact our high-end audio equipment by introducing
>> harmful, high-level, high frequency noise into the AC supply.
>
>AC power supplies are built to resist this sort of thing. However, I have to
>admit that I spent some time thinking of how to build a high end amplifier
>that would have minimal resistance to power line noise. Not surprisingly, I
>came up with a rough approximation of a SET, zero loop feedback and all.
>
>Seems like a great sales opportunity for the usual high end snake oil
>suspects. Here's a step-by-step marketing plan:
>
>(1) Pump the market full of as much badly-designed audio gear as possible.
>SET power amps come to mind. Come up with off-the-wall justifications for
>removing well-known and effective technological solutions to power line nose
>from existing designs.
>
>(2) Then, raise a big fuss about the "...likely impact our high-end audio
>equipment by introducing harmful, high-level, high frequency noise into the
>AC supply."
>
>(3) Have well-known snake-oil technologists (John Curl and Richard Marsh's
>names immediately come to mind) write articles in low-circulation magazines
>and esoteric web sites about the most backward and left-handed means that
>can be thought of to purportedly solve the *problem* of harmful, high-level,
>high frequency noise in the AC supply. If a 50 cent part will do the job,
>come up with off-the-wall justifications for using a $50 part. Phrases like
>"high resolution" and "dielectric absorbtion" come to mind.
>
>(4) Load up the market with a selection of signal line filters, power line
>filters and powerline voltage regenerators to address the problem, which may
>actually exist in some cases because the high end industry already did their
>homework and packed the market with maximally-susceptible equipment in step
>number 1.
>
>(5) Re-engineer the origional bogus equipment designs that the market has
>now expensively band-aided, and reap additional profits by replacing that
>old equipment with equipment conforming to the newly-modified designs.
>
>
>
>> What, if anything, is the audiophile community doing about this issue?
>
>No doubt, they are getting rid to hock the family homestead to load up on
>expensive non-solutions to non-problems. They've got a 20+ year history of
>doing this (separate CD players and DACs, anybody?) so why should they stop
>now. This is where the *true* excitement in audio comes from, after all.
>
>> Is there any action I can take?
>
>Rev up your plastic.
>
>> Is it a real threat to us audiophiles?
>
>It's a truely dire threat, and if you don't believe me check recent and
>up-coming issues of your favorite high end ragazines, and web sites.
>
>> Is there any data available?
>
>Yes, people have been pumping AF, LF, MF, IF, RF, and goodness-knows-what
>into power lines for years. Sometimes they actually tried to do this on
>purpose, and other times they just did it by accident.
>
>> Also, are the power conditioning
>> companies preparing for this potential onslaught?
>
>Smart investors are no-doubt buying their stock.
>
>> I'd appreciate any commentary or sources for more information. I have
>> read extensively
>> on the internet regarding the concept, but I haven't found much
>> available from the audiophile perspective. Thanks for your responses.
>
>Of course this begs the question as to whether I'm really an audiophile, or
>if instead I'm merely a sane mature adule with a modicum of common sense.
>

[Marty Troum]

On 22 Jan 2005 15:04:18 -0800, "John Atkinson"
> wrote:

>
>Robert Morein wrote:
>> "Marty Troum" > wrote in message
>> ...
>> > In the February issue of Stereophile, I read a distressing article
>> > by Jim Austin (page 19) regarding the FCC's support of Broadband
>> > Over Powerline (BPL). It seems that the application of broadband
>> > transmissions to the powerline structure of our communities and
>> > homes will most likely impact our high-end audio equipment by
>> > introducing harmful, high-level, high frequency noise into the AC
>> > supply...
>>
>> I wouldn't worry about it. It could be necessary to install a
>> powerline filter. There is nothing unique about this kind of noise.
>
>Ben Duncan in the UK has done some calculations to determine what
>level of multi-MHz signal would be required to drive a typical
>audio amplifier circuit into slew-rate limiting. I had expected this
>to be in the region a few hundred millivolts; it turns out to be at
>least an order of magnitude lower. Some products may well be in
>trouble without some kind of protection.
>John Atkinson
>Editor, Stereophile

John,
Thank you for your response. Could you be more specific regarding the
type(s) of problem(s) caused and with what type of equipment and also
suggest a potential solution? Thanks again. Also, what would you
recommend as a response, if any, to the FCC ruling?
Marty

[Arny Krueger]

"Marty Troum" > wrote in message


> Although I understand your response and apparent aversion to "snake
> oil" stuff, I am not sure that you answered my humbly-asked question.
> Should I ignore the issue because it will NOT present a problem (in
> your opinion) or should I be concerned?

If your equipment is well-designed, the proposed new networking services
should not pose a threat to your listening enjoyment. I can imagine that
some incompetently-designed high end equipment could possibly have a
problem, because some high end designers act like every bit of relevant
electronics knowledge that has been developed over the past 70 or 80 years
is rubbish. SET power amplifiers are real-world examples of audio gear that
appears to be designed in abject ignorance of much generally accepted and
orthodox technical knowledge. If it was not designed in ignorance, then it
was designed knowingly to go in the opposite direction from
generally-accepted knowledge in this area.

One of the core techniques used by high end marketeers to sell equipment is
to develop structured misapprehensions in the marketplace. Your reference
source Stereophile, has IMO made a business out of raising misapprehensions
and then promoting nonsensical products that purportedly addresses these
non-existent problems, products that sell for unreasonably high prices. This
includes such snake oil products such as Shakti devices which others have
discussed in recent days.

Addressing non-existent problems can be technically speaking, an easy
business. Since the problem doesn't exist except in the potential consumer's
mind, sophisticated technical efforts are not required to address them.
Basically you exhort the consumer until he thinks he has a problem, you
convince him that a certain product will address the non-existent problem
and then you take his money for a token device or service that purports to
address it. In some cases you need to repeatedly exhort the purchaser until
he thinks the problem is solved. The equipment that is sold for this purpose
is only a token, and not an actual representative of any relevant technical
solution, since there is no relevant technical problem in the first place.

> If you have only cynical
> remarks to respond, please don't. I am merely an ignorant person in
> search of some knowledge.

The knowledge you need to have is that Broadband Powerline Networking is
based on applying signals in the 5-35 MHz band to the powerline with the
goal of communicating up to 10,000 feet in a single hop. In normal urban,
suburban and rural contexts; powerlines are already bathed in 5-35 MHz
signals as a consequence of the normal electromagnetic signals that exist
wherever modern civilization is thriving.

Earlier this year I obtained a set of Gigafast Homeplug wireless
communication devices from the local Micro Center store and used them to set
up a wireless network in my home. I used for a few days and noticed no
adverse affects to any of the audio equipment in my home, which includes
both consumer and audio production type equipment.

Here is the web site: http://www.gigafast.com/products/homeplug.htm

Here are the US retail sources of this equipment:
http://www.gigafast.com/buy/united_states.htm

It seems to me that if someone wants to raise concerns over Broadband
Powerline Networking, a reasonable first step would be to set up some
real-world tests. AFAIK Stereophile has not actually done this, even though
doing these tests has only a nominal equipment cost (about $100). Apparently
this sort of a monumental expense would beyond their financial and/or
technical abilities. Note that Stereophile primarily reviews equipment that
is provided for review at no cost.

My test network was composed of a PE902 bridge and a PE 801 USB adaptor used
as described on the following web pages. Note that the PE801 has been
replaced by PE901.

http://www.gigafast.com/products/HomePlug/PE902-EB/PE902-EBx.pdf

http://www.gigafast.com/products/HomePlug/PE901-UI/PE901-UI.htm

Here are some online sources:

http://www.epinions.com/pr-GigaFast_Etherne_GigaFast_HomePlug_Ethernet_Bridge _pe902-eb_Bridge

http://www.epinions.com/Network_Adapters-Power_data-price_bucket_2

[Arny Krueger]

"John Atkinson" > wrote in message
oups.com
> Robert Morein wrote:
>> "Marty Troum" > wrote in message
>> ...
>>> In the February issue of Stereophile, I read a distressing article
>>> by Jim Austin (page 19) regarding the FCC's support of Broadband
>>> Over Powerline (BPL). It seems that the application of broadband
>>> transmissions to the powerline structure of our communities and
>>> homes will most likely impact our high-end audio equipment by
>>> introducing harmful, high-level, high frequency noise into the AC
>>> supply...

>> I wouldn't worry about it. It could be necessary to install a
>> powerline filter. There is nothing unique about this kind of noise.

Agreed. A CB radio down the street is far more likely to cause problems.

> Ben Duncan in the UK has done some calculations to determine what
> level of multi-MHz signal would be required to drive a typical
> audio amplifier circuit into slew-rate limiting. I had expected this
> to be in the region a few hundred millivolts; it turns out to be at
> least an order of magnitude lower. Some products may well be in
> trouble without some kind of protection.

And the relevance of this to the question at hand, is??

One of the core techniques used by high end marketeers to sell equipment is
to develop structured misapprehensions in the marketplace. Stereophile, has
IMO made a business out of raising misapprehensions and then promoting
nonsensical products that purportedly addresses these non-existent
problems, products that sell for unreasonably high prices. This includes
such snake oil products such as Shakti devices which others have discussed
in recent days.

[Marty Troum]

Arny,
Thanks for the info. I appreciate the time you took to respond a
second time. This info is more helpful to me than your first
response. Perhaps I'll better phrase the question in the future!
Marty

On Sun, 23 Jan 2005 05:08:34 -0500, "Arny Krueger" >
wrote:

>The knowledge you need to have is that Broadband Powerline Networking is
>based on applying signals in the 5-35 MHz band to the powerline with the
>goal of communicating up to 10,000 feet in a single hop. In normal urban,
>suburban and rural contexts; powerlines are already bathed in 5-35 MHz
>signals as a consequence of the normal electromagnetic signals that exist
>wherever modern civilization is thriving.
>
>Earlier this year I obtained a set of Gigafast Homeplug wireless
>communication devices from the local Micro Center store and used them to set
>up a wireless network in my home. I used for a few days and noticed no
>adverse affects to any of the audio equipment in my home, which includes
>both consumer and audio production type equipment.
>
>Here is the web site: http://www.gigafast.com/products/homeplug.htm
>
>Here are the US retail sources of this equipment:
>http://www.gigafast.com/buy/united_states.htm
>
>It seems to me that if someone wants to raise concerns over Broadband
>Powerline Networking, a reasonable first step would be to set up some
>real-world tests. AFAIK Stereophile has not actually done this, even though
>doing these tests has only a nominal equipment cost (about $100). Apparently
>this sort of a monumental expense would beyond their financial and/or
>technical abilities. Note that Stereophile primarily reviews equipment that
>is provided for review at no cost.
>
>My test network was composed of a PE902 bridge and a PE 801 USB adaptor used
>as described on the following web pages. Note that the PE801 has been
>replaced by PE901.
>
>http://www.gigafast.com/products/HomePlug/PE902-EB/PE902-EBx.pdf
>
>http://www.gigafast.com/products/HomePlug/PE901-UI/PE901-UI.htm
>
>Here are some online sources:
>
>http://www.epinions.com/pr-GigaFast_Etherne_GigaFast_HomePlug_Ethernet_Bridge _pe902-eb_Bridge
>
>http://www.epinions.com/Network_Adapters-Power_data-price_bucket_2
>

[John Atkinson]

Marty Troum wrote:
> >Ben Duncan in the UK has done some calculations to determine what
> >level of multi-MHz signal would be required to drive a typical
> >audio amplifier circuit into slew-rate limiting. I had expected this
> >to be in the region a few hundred millivolts; it turns out to be at
> >least an order of magnitude lower. Some products may well be in
> >trouble without some kind of protection.
>
> Thank you for your response. Could you be more specific regarding
> the type(s) of problem(s) caused and with what type of equipment and
> also suggest a potential solution?

I had assumed, like Arny Krueger, that this was a non-issue due both
to the low levels of MHz signal and to the RF rejection properties of
audio components' power supplies. It appears I was wrong on both
counts, that the RF levels might be considerably higher than the home
networking devices currently around, and that it can't be taken for
granted that the power supply will block that energy from reaching
the audio circuitry.

The problem, according to Duncan, is that even a few millivolts of MHz
energy leaking into the audio circuits can drive solidstate devices
into slew-rate limiting, hence non-linear behavior.

This is already a problem, BTW, when measuring the distortion
performance of class-D or "switching" amplifiers, in that the RF
energy present in their output (even after the low-pass filtering
between the output devices and the speaker terminals) can drive test
equipment into non-linear behavior.

> Also, what would you recommend as a response, if any, to the FCC
> ruling?

The audio industry needs to respond through their Washington-based
trade organization, the CEA, whose CEO, Gary Shapiro, is
well-acquainted with outgoing FCC chairman Michael Powell.
John Atkinson
Editor, Stereophile

[Robert Morein]

"John Atkinson" > wrote in message
oups.com...
>
> Marty Troum wrote:
> > >Ben Duncan in the UK has done some calculations to determine what
> > >level of multi-MHz signal would be required to drive a typical
> > >audio amplifier circuit into slew-rate limiting. I had expected this
> > >to be in the region a few hundred millivolts; it turns out to be at
> > >least an order of magnitude lower. Some products may well be in
> > >trouble without some kind of protection.
> >
> > Thank you for your response. Could you be more specific regarding
> > the type(s) of problem(s) caused and with what type of equipment and
> > also suggest a potential solution?
>
> I had assumed, like Arny Krueger, that this was a non-issue due both
> to the low levels of MHz signal and to the RF rejection properties of
> audio components' power supplies. It appears I was wrong on both
> counts, that the RF levels might be considerably higher than the home
> networking devices currently around, and that it can't be taken for
> granted that the power supply will block that energy from reaching
> the audio circuitry.
>
[snip]
>
But this should be filterable with enough iron and enough capacitance, no?
Also, switching power supplies prevelant in computers already inject huge
amounts of RF from the switching waveform edges.
All though the transitions are at a much lower frequency, the speed of the
transitions means that the noise spectrum extends quite high.
The level of backfeed from these switchers is already much higher than the
"troublesome" values, since there is measurable power factor involved.
Thus the environment may already exist.

[Arny Krueger]

"John Atkinson" > wrote in message
oups.com
> Marty Troum wrote:
>>> Ben Duncan in the UK has done some calculations to determine what
>>> level of multi-MHz signal would be required to drive a typical
>>> audio amplifier circuit into slew-rate limiting. I had expected this
>>> to be in the region a few hundred millivolts; it turns out to be at
>>> least an order of magnitude lower. Some products may well be in
>>> trouble without some kind of protection.
>>
>> Thank you for your response. Could you be more specific regarding
>> the type(s) of problem(s) caused and with what type of equipment and
>> also suggest a potential solution?
>
> I had assumed, like Arny Krueger, that this was a non-issue due both
> to the low levels of MHz signal and to the RF rejection properties of
> audio components' power supplies. It appears I was wrong on both
> counts, that the RF levels might be considerably higher than the home
> networking devices currently around, and that it can't be taken for
> granted that the power supply will block that energy from reaching
> the audio circuitry.

One place that we differ John is that I actually have experimented with
relevant broadband powerline networking hardware.

> The problem, according to Duncan, is that even a few millivolts of MHz
> energy leaking into the audio circuits can drive solidstate devices
> into slew-rate limiting, hence non-linear behavior.

I imagine that if you line up enough exceptional circumstances, that might
even happen.

> This is already a problem, BTW, when measuring the distortion
> performance of class-D or "switching" amplifiers, in that the RF
> energy present in their output (even after the low-pass filtering
> between the output devices and the speaker terminals) can drive test
> equipment into non-linear behavior.

I've done some measurements on Class D equipment, and other than it having a
number of technical problems, never gave me a problem.

>> Also, what would you recommend as a response, if any, to the FCC
>> ruling?

> The audio industry needs to respond through their Washington-based
> trade organization, the CEA, whose CEO, Gary Shapiro, is
> well-acquainted with outgoing FCC chairman Michael Powell.

The CEA has a built-in conflict of interest, because home networking is one
of the market segments that they serve.

http://ce.org/ce_technologies/display.asp?id=Home%20Networking

[John Atkinson]

Robert Morein wrote:
> "John Atkinson" > wrote in message
> oups.com...
> > I was wrong on both counts: the RF levels might be considerably
> > higher than the home networking devices currently around; and it
> > can't be taken for granted that the power supply will block that
> > energy from reaching the audio circuitry.
> >
> [snip]
> >
> But this should be filterable with enough iron and enough
capacitance,
> no?

I would have thought so. But whether any particular component will be
affected or not, and thus need additional filtering or not, is going to
be a crapshoot.

> Also, switching power supplies prevelant in computers already inject
> huge amounts of RF from the switching waveform edges...Thus the
> environment may already exist.

I agree, but the backfeed from these supplies into the mains waveform
is unpredictable. I think that some of the contrary opinions that some
of the audio products that use switch-mode power supplies -- the
Linn Klimax amplifiers come to mind -- may be due to the varying
susceptibility of the owner's other components to such VHF hash
injected back into the wall supply.
John Atkinson
Editor, Stereophile

[John Atkinson]

Arny Krueger wrote:
> "John Atkinson" > wrote in message
> oups.com
> > This is already a problem, BTW, when measuring the distortion
> > performance of class-D or "switching" amplifiers, in that the RF
> > energy present in their output (even after the low-pass filtering
> > between the output devices and the speaker terminals) can drive
test
> > equipment into non-linear behavior.
>
> I've done some measurements on Class D equipment, and other than it
> having a number of technical problems, never gave me a problem.

It's not impossible. As you use sound-card-based test gear, the
card's antiliasing filter will eliminate such RF hash from the
digital data being analyzed and it is possible that the front-end
stage of the card was not driven into non-linear behavior. But unless
you know for a fact that your test equipment is not driven into
slew-rate limiting by RF spuriae, you cannot be sure that all the
distortion harmonics are due to the device under test. Some may be
due to the test gear. That is all I am saying.

Audio Precision, for example, has published a series of white
papers on this subject in the past year or so -- see
http://www.audioprecision.com/index.php?page=news&id=1000000065 --
and recommends using a bandpass filter between amplifier and test
gear in such circumstances.

John Atkinson
Editor, Stereophile

[Arny Krueger]

"Robert Morein" > wrote in message


> But this should be filterable with enough iron and enough
> capacitance, no?

Right. Just about every modern audio component power supply has a
transformer in it. Better designs go out of their way to minimize
capacitance between the primary and secondary windings. The freqency
response of the the magnetic coupling is absolutely horrid which means that
it acts like a giant interfereance filter. Ditto for the remaining parts in
a linear power supply.

>Also, switching power supplies prevelant in
> computers already inject huge amounts of RF from the switching
> waveform edges.

Switching power supplies are increasingly common in consumer audio and video
gear.

> All though the transitions are at a much lower
> frequency, the speed of the transitions means that the noise spectrum
> extends quite high. The level of backfeed from these switchers is
> already much higher than the "troublesome" values, since there is
> measurable power factor involved. Thus the environment may already
> exist.

Power lines haven't become more pristine as time has marched on, although
sparking relays and motors have largely disappeared from the scene.

The people with a more legitimate concern IMO are the hams.

[Rudy]

On 23-Jan-2005, "Arny Krueger" > wrote:

> Addressing non-existent problems can be technically speaking, an easy
> business. Since the problem doesn't exist except in the potential
> consumer's mind, sophisticated technical efforts are not required to
> address them.
> Basically you exhort the consumer until he thinks he has a problem, you
> convince him that a certain product will address the non-existent problem

hmmm. is it like the sales pitch that made you buy the water treatment
problem solving 'kit' , Arn ?

Rudy

[WVK]

John Atkinson wrote:
> Robert Morein wrote:
>
>>"Marty Troum" > wrote in message
...
>>
>>>In the February issue of Stereophile, I read a distressing article
>>>by Jim Austin (page 19) regarding the FCC's support of Broadband
>>>Over Powerline (BPL). It seems that the application of broadband
>>>transmissions to the powerline structure of our communities and
>>>homes will most likely impact our high-end audio equipment by
>>>introducing harmful, high-level, high frequency noise into the AC
>>>supply...
>>
>>I wouldn't worry about it. It could be necessary to install a
>>powerline filter. There is nothing unique about this kind of noise.
>
>
> Ben Duncan in the UK has done some calculations to determine what
> level of multi-MHz signal would be required to drive a typical
> audio amplifier circuit into slew-rate limiting. I had expected this
> to be in the region a few hundred millivolts; it turns out to be at
> least an order of magnitude lower. Some products may well be in
> trouble without some kind of protection.
> John Atkinson
> Editor, Stereophile
>
I bumped into a fellow at at trade show who said that his company was
doing a trial of PLB in either OH or PA. He said that in US it is too
expensive to send the signal to each house because a transformer feeds
few houses (4?) and needs to be bypassed. They are using a Wi-Fi
antenna placed on their utility poles. Apparently England feeds more
houses with one transformer (maybe because of 220V?).

Some think PLB is too little too late. Consider that Verizon is
currently spending billions building a FTTP network.

WVK

[Arny Krueger]

"WVK" > wrote in message
m

> I bumped into a fellow at at trade show who said that his company was
> doing a trial of PLB in either OH or PA. He said that in US it is too
> expensive to send the signal to each house because a transformer feeds
> few houses (4?) and needs to be bypassed.

This could be true.

>They are using a Wi-Fi
> antenna placed on their utility poles. Apparently England feeds more
> houses with one transformer (maybe because of 220V?).

The English are probably not power hogs on same scale as the US. They
probably aren't all driving SUVs, either.

> Some think PLB is too little too late. Consider that Verizon is
> currently spending billions building a FTTP network.

That would be FTTP as in "Fibre To The Premises"?

I guess it was coming - someone must have made a quantum leap in fibre
termination costs.

[WVK]

Arny Krueger wrote:

> "WVK" > wrote in message
> m
>
>
>> I bumped into a fellow at at trade show who said that his company was
>>doing a trial of PLB in either OH or PA. He said that in US it is too
>>expensive to send the signal to each house because a transformer feeds
>>few houses (4?) and needs to be bypassed.
>
>
> This could be true.
>
>
>>They are using a Wi-Fi
>>antenna placed on their utility poles. Apparently England feeds more
>>houses with one transformer (maybe because of 220V?).
>
>
> The English are probably not power hogs on same scale as the US. They
> probably aren't all driving SUVs, either.
>
>
>>Some think PLB is too little too late. Consider that Verizon is
>>currently spending billions building a FTTP network.
>
>
> That would be FTTP as in "Fibre To The Premises"?
http://arstechnica.com/news.ars/post/20041021-4339.html
>
> I guess it was coming - someone must have made a quantum leap in fibre
> termination costs.

It's a passive optical network (PON). One fiber out of the Central
Office eventually splits into 32 fibers, one per location. The
deployment is in response to Verizon losing 10,000 customers a day to
the competition.

WVK