Dick,

I'm not at all sure who uses what spectrum in the areas where they are
testing BPL, but I'd bet coffee for a week that those folks studied the
situation carefully before proceeding. Where did they test (I don't know of
all areas and I'm asking a sincere question)? The "promise" of BPL is to
serve areas that are not served well by cable or DSL. Did they test a
fairly substantial area in the country where they could demonstrate
far-flung connections to the BPL, or did they test in densely populated
areas that are already served by various broadband connection (where fire,
police, emergency, etc. are very likely not on low band VHF)? Also, FM
broadcasting is usually located near large population areas (since signals
tend to die off pretty quickly after 40 or 60 miles). This means that if
you have BPL in a city, it is unlikely that residents will experience
capture effect on the FM receivers since they will be getting *huge* signals
on their FM receivers. I note the "neon sign" comment in the thread. Neon
signs are usually found in cities. Those test sites are likely located
either in a city or in an area where the money interests already checked the
FCC site to ensure no low band VHF use by police, fire, ambulance, etc.

Any thoughts on this, or am I crazy?


73 from Rochester, NY
Jim AA2QA


"Dick Carroll" wrote in message
...

Before I retired I was a field engineer working with a statewide
public safety organization which uses low band VHF for base to car
communications statewide, and that system is still virtually as I left
it nearly 10 years ago. I have learned that they are aware of the BPL
docket and filed in opposition, and have some idea that it will impact
their communications, but I wonder if they have a clear view of what
looms should BPL be widely implemented. While working I spent
considerable time on RF noise issues, and I am rather sure that such a
radio system cannot coexist with BPL.

What happens is that when the noise intererence reaches a certain
level, in a FM receiver the limiter saturates, and even a strong
on-channel signal will not cause the squelch to open. The reciever
remains quiet, and the call is unanswered.
I was able to locate one troublesome noise source which was reported
as repeater trouble in that the repeater would ocassionally go quiet in
mid-transmission when a car was calling in. By the time I would drive
the substantial distance to the repeater, a thorough checkout found no
problem with the repeate equipment whatever. After several fruitless
trips and attempts to find the trouble, I finally happened to be onsite
when the trouble appeared, and it was all limiter saturation. Looking
around outside while the noise was present in an attempt to spot a
source in the local rural area, I soon found it- an arc welder in a shop
several hundred yards away. When the welder was in use, the arc caused
noise that saturated the receiver limiter, effectively shutting down the
repeater. We relocated that repeater to a more isolated site where it
still functions as intended.
That example is but one case. BPL will, following power lines, also
follow roads and streets since power lines follow streets and
highway/road rights of way everywhere - the same places where police and
highway patrol units'communications are active. The interference issue
simply WILL cause something drastic to be implemented, what I don't
know. If common sense has anything to do with it, BPL will be sent
packing. Widesp[read implementation of BPL spells the end of lowband VHF
use by public safety organizations. And with states' budgets in the
deflated condition they are in most places, the funding will not be
available to replace those systems in the forseeable future.

I just called a former co-worker who is still working, and asked him
if the organization knows that there is a BPL test site in the state.
He said they did not. I suggested he might want to pass the word on up
the chain so that they might want to send a mobile unit into the test
area to get firsthand information on just what the effects might be. I'm
also passing along all the info I've gathred here and from other
sources. We'll need all the help we can get on this turkey.

In short, I'm coninced that while APCO and others may know
of the BPL docket I wonder if they have a very clear concept of
what it will do to them where low band VHF is used.
For instance, what have you heard from the state of Calorfinia, which
is reported to use low band VHF for their statewide Highway Patrol, and
has over 5,000 mobile units with no telling how many base stations?
I have heard nothing whatever from anyone there on BPL.

It seems evident that the BPL people are not publishing the existance
of these very small test sites any more widely than necessary. So, they
won't garner very many,if any, BPL-specific complaints, will they? And
they'll be able to say "We must not be causing destructive interference
since we haven't generated complaints". Of course limiting the numbers
of users in test areas to a very few drastically limits the amount of
interference potential. With so few BPL users online there *won't* be
much interference caused, thus few or no complaints. Then they will
conveniently pass over this fact, and the decision makers won't know the
difference.

Someone with clout needs to take them to task with the FCC and force
them to use much broader test areas with much more realistic noise
levels generated so that a more realistic noise picture can be
evaluated. As it stands, they may well get what they want by default.

Dick W0EX



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"Jim Hampton" wrote in message
...
Dick,

I'm not at all sure who uses what spectrum in the areas where they are
testing BPL, but I'd bet coffee for a week that those folks studied the
situation carefully before proceeding. Where did they test (I don't know
of
all areas and I'm asking a sincere question)?

The fact of the matter is that the ONLY serious technical studies
presented to the FCC in their Notice of Inquiry on BPL came from
the good work of Ed Hare, W1RFI, and his colleagues at ARRL.

The "access BPL" industry has done essentially nothing but "hand-
waving" and ignoring/denying that the problem exists. They want
to make $$$ ... and they don't appear to give a damn about the
impact on the other users of HF.

That they claim that "power wires don't radiate" (when NEC models,
as well as plain old common sense, indicate that they do) and that
"BPL is a 'point source' radiator" (how one can make that argument
when what they are building is essentially a large, distributed antenna
system) clearly indicate their deep state of "don't confuse the issue
with the facts" denial.

The "promise" of BPL is to serve areas that are not served well
by cable or DSL.

While DSL is not available in all areas due to the distance from the
central office factor and the phone companies' slow rollout in areas
of lower population density, acccording to the latest statistics I've
seen, cable "passes" 97%+ of US households. There are also
internet via satellite services available, using dishes like (sometimes
the same dish as) satellite TV services. There are also "WISPs"
who provide services using more appropriate spectrum in the low
microwave bands.

The business model for BPL is WAY less than compelling and its
technical suitability is poor as well, not only because of interference
TO the wide variety of licensed HF users, but also because of the
potential for interference to the BPL system FROM those licensed
users ... and BPL will have NO claim of protection from such interference.
My belief is that consumers deserve a more robust and reliable means
of receiving broadband internet services - one that doesn't present the
(bi-directional) interference issues of BPL - and that there are a number
of such alternatives available already.

Did they test a
fairly substantial area in the country where they could demonstrate
far-flung connections to the BPL, or did they test in densely populated
areas that are already served by various broadband connection (where fire,
police, emergency, etc. are very likely not on low band VHF)?

Ed has a better overall view of the current deployments of BPL, but I know
they are few and limited in scope at the moment.

Also, FM
broadcasting is usually located near large population areas (since signals
tend to die off pretty quickly after 40 or 60 miles). This means that if
you have BPL in a city, it is unlikely that residents will experience
capture effect on the FM receivers since they will be getting *huge*
signals
on their FM receivers.

S9+10 on a VERY short whip (an "Outbacker Joey") is a pretty huge
signal to me ... with BPL proposing to go up to 80 MHz, I would
think that the FM broadcast band is at relatively low risk, though FM
receivers could experience some degree of "desense" if the BPL
signal at the front end was strong enough due to proximity.

I note the "neon sign" comment in the thread. Neon
signs are usually found in cities.

The "neon sign" assertion by the representative of PPL (the Emmaus
BPL system operator) is *pure* BS ... the signature was SS, NOT
a neon sign ...

Those test sites are likely located
either in a city or in an area where the money interests already checked
the
FCC site to ensure no low band VHF use by police, fire, ambulance, etc.

I think you're giving them FAR too much credit for caring about anything
but deploying BPL ...

Carl - wk3c

"Jim Hampton" wrote in message ...
Dick,

I'm not at all sure who uses what spectrum in the areas where they are
testing BPL

Nobody knows how much interference the stuff could generate
eventually. The BPL proponents are advertising their intent to run
from 2 thru 80 Mhz inclusive. At considerably higher power levels than
they're using in the current test areas. There's a major threat in
itself and it's not being tested.

but I'd bet coffee for a week that those folks studied the
situation carefully before proceeding.

Would not surprise me one bit. But then along came hams with HF mobile
rigs like Carl wk3c, Ed Hare w1rfi and Bob Davidson w3hj and myself
who took ham radio into BPL test areas and are blowing the whistle.
Loudly.

Where did they test (I don't know of
all areas and I'm asking a sincere question)?

Go to the ARRL site for the complete list of known test areas. All of
those I know about so far are in the NE corridor in densly-populated
upscale +/- residential neigborhoods. Because that's where the money
is. Which also happen to be the same sorts of neighborhoods in which a
lot of hams live too.

The "promise" of BPL is to
serve areas that are not served well by cable or DSL

Total BS. BPL is quite expensive to deploy. A fiber optic feed line or
cable TV line has to run parallel to the power lines. These feed lines
inject the BPL signals into the low voltage power lines via taps
roughly at every street intersection or the neighborhood has no BPL.
If there isn't any cable or DSL service in your locale because there
isn't any ROI in it for those service providers there most likely
won't be any BPL either. They're all chasing the same dollars.

Did they test a
fairly substantial area in the country where they could demonstrate
far-flung connections to the BPL,

Absolutely not. There are no "far-flung connections" to BPL per above.
In the Emmaus PA test area which I've visited BPL is only distributed
along a few blocks of maybe 3-4 residential streets. Completely
inconclusive test program to the point of being a contrived scam.

or did they test in densely populated
areas that are already served by various broadband connection

Seems like.

(where fire,
police, emergency, etc. are very likely not on low band VHF)?

Dunno. There are at least three test sites concentrated in the Lehigh
Valley region in PA and there are very few if any emergency services
still using lo-band VHF in PA. I have not seen any references to BPL
being tested in places like California and Dick's Missouri where
lo-band is still in use. What a big surprise eh?

Also, FM
broadcasting is usually located near large population areas (since signals
tend to die off pretty quickly after 40 or 60 miles). This means that if
you have BPL in a city, it is unlikely that residents will experience
capture effect on the FM receivers since they will be getting *huge* signals
on their FM receivers.

BPL as presently conceived is not supposed to run in either the AM or
FM broadcast bands. Plus there are guard bands between BPL and both
broadcast bands. 'Nother big surprise.

I note the "neon sign" comment in the thread. Neon
signs are usually found in cities.

There are "point source" neon signs fifty miles north of Butte,
they're *everywhere*.

Those test sites are likely located
either in a city or in an area where the money interests already checked the
FCC site to ensure no low band VHF use by police, fire, ambulance, etc.

Covered above.


Any thoughts on this, or am I crazy?

Certainly you're a crazy. All us frequent posters in this NG are
certified crazies. Where the hell have YOU been?!


73 from Rochester, NY
Jim AA2QA

w3rv



"Dick Carroll" wrote in message
...

Before I retired I was a field engineer working with a statewide
public safety organization which uses low band VHF for base to car
communications statewide, and that system is still virtually as I left

The ARRL site, http://www.arrl.org/tis/info/HTML/plc/#Field , provides
links to the following information:

"PLC is a "carrier-current" system, designed to intentionally conduct
signals using electrical wiring. Although a carrier-current device is an
unintentional emitter, because the power lines have such a significant
potential to radiate and because a practical carrier-current device
generally needs more signal than the permitted conducted emissions
levels for unintentional emitters, carrier-current devices are not
required to meet those conducted-emissions limits, but are required to
meet the general radiated emissions limits in Sec. 15.209.

§ 15.209 states that the radiated emission limits of intentional
radiators generally can't exceed the field strength levels specified in
the following table:

Frequency (MHz) Field Strength (microvolts/meter @meters)

0.009-0.490 2400/F(kHz) 300

0.490-1.705 24000/F(kHz) 30

1.705-30.0 30 30

30-88 100 3

88-216 150 3

216-960 200 3

Above 960 500 3

Carrier-current devices are "Verified" as described in the Part-15
rules. This means that the manufacturer is required to test them to
ensure that they comply with the FCC regulations. Under the present
rules, they must be tested at 3 typical locations. "

Note that the HF Spectrum allows a S8 to S9 signal level, 30 uV/m at 30
meters distance.

Brian,

I don't know about you, but I received a whole week pass from Belleveu

73 from Rochester, NY
Jim AA2QA


"Brian Kelly" wrote in message
om...
"Jim Hampton" wrote in message
...
Dick,
Any thoughts on this, or am I crazy?

Certainly you're a crazy. All us frequent posters in this NG are
certified crazies. Where the hell have YOU been?!


w3rv




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In article , "Carl R. Stevenson"
writes:

The fact of the matter is that the ONLY serious technical studies
presented to the FCC in their Notice of Inquiry on BPL came from
the good work of Ed Hare, W1RFI, and his colleagues at ARRL.

Yep.

The "access BPL" industry has done essentially nothing but "hand-
waving" and ignoring/denying that the problem exists. They want
to make $$$ ... and they don't appear to give a damn about the
impact on the other users of HF.

Besides ignoring the technical weaksnesses of BPL, they're also ignoring the
really poor business model that drives it.

That they claim that "power wires don't radiate" (when NEC models,
as well as plain old common sense, indicate that they do) and that
"BPL is a 'point source' radiator" (how one can make that argument
when what they are building is essentially a large, distributed antenna
system) clearly indicate their deep state of "don't confuse the issue
with the facts" denial.

It should also be mentioned that the location and existence of test sites was
kept very quiet until ARRL/W1RFI blew the whistle. Representatives of radio
services were neither invited nor even informed of BPL tests.

One of the simplest and most positive tests is to turn the BPL service on and
off and observe changes in interference, thus identifying if BPL is the source.
But to my knowledge no BPL test site has done such tests.

The "promise" of BPL is to serve areas that are not served well
by cable or DSL.

While DSL is not available in all areas due to the distance from the
central office factor and the phone companies' slow rollout in areas
of lower population density, acccording to the latest statistics I've
seen, cable "passes" 97%+ of US households. There are also
internet via satellite services available, using dishes like (sometimes
the same dish as) satellite TV services. There are also "WISPs"
who provide services using more appropriate spectrum in the low
microwave bands.

Agreed. But there's mo

Access-BPL is really meant as a "last mile" system, to avoid the need to wire
houses for cable or install special filters and modems. So the fiber still
needs to get within a certain distance of your house, same as with DSL.

The main selling point for Access-BPL is that you can just plug a BPL modem
line into any wall outlet, and you're connected. Your entire house wiring
becomes an internet connection - and also an antenna to radiate BPL noise. So
even if all services are buried, you'll still have noise from the house wiring
radiating.

The BPL signal travels on the medium voltage (4-13 kV) distribution wire(s) and
is then coupled around the pole pig transformers with special couplers. In most
neighborhoods other than those of very low density, a transformer feeds a few
homes, so everyone's wiring gets the BPL signal even if only one customer is
signed up. Indeed, if a coupler is left in place, everyone's house wiring gets
the signal even if no one is signed up.

The couplers and fiber/MV converters mean that BPL has significant installation
costs even if they don't have to do any installation in customer's houses.

The business model for BPL is WAY less than compelling and its
technical suitability is poor as well, not only because of interference
TO the wide variety of licensed HF users, but also because of the
potential for interference to the BPL system FROM those licensed
users ... and BPL will have NO claim of protection from such interference.
My belief is that consumers deserve a more robust and reliable means
of receiving broadband internet services - one that doesn't present the
(bi-directional) interference issues of BPL - and that there are a number
of such alternatives available already.

Very well-said and absolutely true.

Did they test a
fairly substantial area in the country where they could demonstrate
far-flung connections to the BPL, or did they test in densely populated
areas that are already served by various broadband connection (where fire,
police, emergency, etc. are very likely not on low band VHF)?

Ed has a better overall view of the current deployments of BPL, but I know
they are few and limited in scope at the moment.

There are also different systems being tried out, so what you hear on the
Emmaus test site video may not be the same as what is experienced elsewhere.

Also, FM
broadcasting is usually located near large population areas (since signals
tend to die off pretty quickly after 40 or 60 miles). This means that if
you have BPL in a city, it is unlikely that residents will experience
capture effect on the FM receivers since they will be getting *huge*
signals on their FM receivers.

S9+10 on a VERY short whip (an "Outbacker Joey") is a pretty huge
signal to me ... with BPL proposing to go up to 80 MHz, I would
think that the FM broadcast band is at relatively low risk, though FM
receivers could experience some degree of "desense" if the BPL
signal at the front end was strong enough due to proximity.

What about harmonics? The BPL signals on the video sounded like they had pretty
fast risetimes.

I note the "neon sign" comment in the thread. Neon
signs are usually found in cities.

The "neon sign" assertion by the representative of PPL (the Emmaus
BPL system operator) is *pure* BS ... the signature was SS, NOT
a neon sign ...

And did they turn off the BPL for a few moments to demonstrate that it was a
neon sign and not the BPL? One guess.....

Those test sites are likely located
either in a city or in an area where the money interests already checked
the
FCC site to ensure no low band VHF use by police, fire, ambulance, etc.

I think you're giving them FAR too much credit for caring about anything
but deploying BPL ...

Exactly!

Something else to watch out for.....

Because different systems are being tried in different locations, proponents of
each system will probably proclaim the *their* system doesn't have that problem
- what you heard at the Podunk site is Brand X BPL.

73 es tnx Carl de Jim, N2EY

Carl R. Stevenson wrote:




S9+10 on a VERY short whip (an "Outbacker Joey") is a pretty huge
signal to me ... with BPL proposing to go up to 80 MHz, I would
think that the FM broadcast band is at relatively low risk, though FM
receivers could experience some degree of "desense" if the BPL
signal at the front end was strong enough due to proximity.

TV channels 2, 3, 4, and 5 will get clobbered by the junk going up to 80MHz.
The video signal is AM modulated onto the channel carrier (with a
portion of the
lower sideband suppressed) and will have no ability to reject the BPL
noise.
The effect would be somewhat similar to a sparky vacuum cleaner motor
throwing
white and black spots throuout the picture. The sound, being FM, will fare
better. Well, there's digital HDTV, but most everyone still uses analog TV.
And I don't get cable or satellite.

"Jim Hampton" wrote in message ...
Brian,

I don't know about you, but I received a whole week pass from Belleveu

73 from Rochester, NY
Jim AA2QA


So you got three hots and a cot AND a weeks pass (all paid) and the
rest of us have to learn it because you had to do it?

That's not the way it works anymore.

I'm no longer an instrument of national policy.

Dave Shrader wrote in message .net...
The ARRL site, http://www.arrl.org/tis/info/HTML/plc/#Field , provides
links to the following information:

"PLC is a "carrier-current" system, designed to intentionally conduct
signals using electrical wiring. Although a carrier-current device is an
unintentional emitter, because the power lines have such a significant
potential to radiate and because a practical carrier-current device
generally needs more signal than the permitted conducted emissions
levels for unintentional emitters, carrier-current devices are not
required to meet those conducted-emissions limits, but are required to
meet the general radiated emissions limits in Sec. 15.209.

§ 15.209 states that the radiated emission limits of intentional
radiators generally can't exceed the field strength levels specified in
the following table:

Frequency (MHz) Field Strength (microvolts/meter @meters)

0.009-0.490 2400/F(kHz) 300

0.490-1.705 24000/F(kHz) 30

1.705-30.0 30 30

30-88 100 3

88-216 150 3

216-960 200 3

Above 960 500 3

Carrier-current devices are "Verified" as described in the Part-15
rules. This means that the manufacturer is required to test them to
ensure that they comply with the FCC regulations. Under the present
rules, they must be tested at 3 typical locations. "

What's the FCC definition of "typical locations"??

Note that the HF Spectrum allows a S8 to S9 signal level, 30 uV/m at 30
meters distance.

15.209 is the problem, it's grossly outdated, did not foresee anything
like BPL and the limits needs to be revised downward which is one
piece of this brawl. Ref: Tailpipe emissions regs, same basic problem,
different pollution media.

Another piece of it is that the BPL crowd wants permission to bust the
already inadequate limits in 15.209. They're playing the regulatory
loopholes game. The Japanese jumped past their regulatory Catch-22
techo-babble and abolished BPL period. We need to follow the Japanese
lead and we're working on it.

w3rv

On 15 Oct 2003 22:30:17 -0700, Brian Kelly wrote:

This means that the manufacturer is required to test them to
ensure that they comply with the FCC regulations. Under the present
rules, they must be tested at 3 typical locations. "

What's the FCC definition of "typical locations"??

De facto: any place where the results support the stand that one is
advocating.

--
73 de K2ASP - Phil Kane