Pat, The objections are much the same in both cases. BPL (in-home or "access") operates in the HF spectrum over power lines. Power lines were never designed to serve as transmission lines in the HF spectrum. The signal levels used for in-home systems are 25 to 30 dB above the CISPR 22 Class B limits when measured with a LISN as is done in CISPR 22. This drive level was selected to allow HomePlug devices to meet the FCC's radiated emissions limit (30 dBuV/m at 30 meters) for carrier current devices in 25 representative homes a number of years ago. This makes these devices legal in the US. There is no such category in CISPR 22. Thus is it currently required that BPL devices be tested in the normal fashion for power line conducted emissions, a test which they fail. BPL (PLC, PLT) manufacturers have used other test methods in the EU to claim compliance with the essential requirements of the EMC Directive and work has been on-going for about 10 years in CISPR to try and come u! p with an acceptable measurement method and limits. Acceptable to the BPL folks and to those who want no reduction in the level of protection presently provided by CISPR 22. Obviously a difficult task.
When I ran an experiment in my home a number of years ago I demonstrated that for my installation the notching done by the HomePlug Alliance adequately protected my ability to use the amateur radio bands within the range of spectrum used by the product (7 to 22 MHz). Outside the amateur radio bands there was no question that the device was operating with significant interference received on all frequencies in the 7 to 22 MHz range that were not notched. Broadband noise, not relatively narrow band emissions as one would see from the clocks and other circuits in a computer. This indicates to me that the CISPR 22 limits for power line conducted emissions are adequate (the notches took the emissions down to about the Class B limits in the lab). So now the question comes up. Why is it acceptable to notch only the amateur radio bands and not frequencies used by other radio communication services? The argument is that the most common use of the HF spectrum in the domestic environment is amateur radio. Amateur radio operators are technically savvy and organized. If you interfere with them, complaints to the national regulator (FCC in the US) are likely. Protect them from interference by not utilizing the bands where they are licensed and you greatly reduce the potential for harmful interference in the home. Experience over the past years has suggested that this approach was correct. I am not aware of any significant interference complaints resulting from the operation of properly notched BPL systems. At least not complaints from amateur radio operators about interference in the amateur radio bands. So why not protect the other licensed users of the HF spectrum? If you look at the FCC Rules, Part 15, Subpart G provides regulations for Access BPL systems. These cover much wider areas with long overhead power lines as the path. They have a higher potential for radiating significant levels of RF energy. The FCC Rules provide a list of prohibited frequencies for these systems and a long list of "exclusion zones" where they may not be installed. The prohibited frequencies are designed to protect aeronautical HF radio installations (ground and airborne) from interference. The exclusion zones protect a number of users (government) of the spectrum by keeping installations a minimum distance from the communications facilities. Clearly the FCC is concerned about the interference potential for these systems as it provides protection for certain uses of the spectrum in its Rules. And, by notching the amateur radio bands, the operators of access BPL systems also minimize the! chance of causing interference to this service. Ghery S. Pettit From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Monday, May 24, 2010 9:34 AM To: [email protected] Subject: RE: [PSES] CE Standard for Power Lines data Transmission System I have no experience with BPL, so the discussion is interesting. 1) Ghery Pettit wrote that there was no 'Access BPL' in his area. 'Access BPL' appears to be communication over long-distance power lines. Charles Grasso (in a different email) talks about having 8 PLC devices in his home. I guess this is home-use BPL. Are the objections the same in each case, or is the 'long-distance' BPL variety the one that has the most detractors? 2) What does BPL interference sound like? Is it really broadband noise (like the noise floor rising), or is it burst-type noise, like the noise heard if you put a radio next to a computer? Pat Lawler EMC Engineer SL Power Electronics Corp. "Pettit, Ghery" <[email protected]> wrote on 05/24/2010 08:35:07 AM: > Not in the ham bands, thanks to notching by HomePlug devices. No > Access BPL in our area. > > Ghery S. Pettit > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of > Grasso, Charles > Sent: Sunday, May 23, 2010 9:04 AM > To: [email protected]; [email protected]; [email protected] > Subject: RE: [PSES] CE Standard for Power Lines data Transmission System > Question to Ham operators out there: > Have you noticed an issue with PLC (home devices)? > ________________________________________ > From: [email protected] [[email protected]] On Behalf Of Dennis Ward > [[email protected]] > Sent: Friday, May 21, 2010 8:43 AM > To: [email protected]; [email protected] > Subject: RE: [PSES] CE Standard for Power Lines data Transmission System > Ahh but just give it time and BPL/PLC will do the same thing - > become very inexpensively made transmitters, the manufacturers of > which think they have as much right to the spectrum as a licensed > device. And let's not forget the real issue here. Licensed devices > have 'promised protection' by regulators while unlicensed devices > have no promise of protection only the caution that if they cause > interference, they are to stop transmitting or potentially suffer > fines up to the individual use of a single device (like that would > ever happen how - too bad). > Of course now days, what with the lack of concern etc in spectrum > use, it will sooner or later jump back to the days of spark gap > transmitters - if anyone gets the drift. > What concerns me is the seeming lack of enforcement from the FCC in > all this. Thinking people and or manufacturers will 'play fair' is > a naïve position. > > Dennis Ward > Director of Engineering > American TCB > Certification Resource for the Wireless Industry www.atcb.com<http: > //www.atcb.com/> > 703-847-4700 fax 703-847-6888 > direct - 703-880-4841 > From: [email protected] [mailto:[email protected]] On Behalf Of > Cortland Richmond > Sent: Friday, May 21, 2010 4:57 AM > To: [email protected] > Subject: RE: [PSES] CE Standard for Power Lines data Transmission System > Ham operators were prominent in the fight because we are competent > enough to make reasoned valid arguments (many of us, anyhow) and > among those first to be harmed. We have reason. We are, let us say, > "disproportionately represented" in the EMC professions, too. > A regulatory scheme has taken root over the last decades that is > reactive, not proactive, and insists no regulatory issue exists > unless and until someone is harmed by a violation. This has made > things considerably easier on manufacturers who fall under PArt 15, > for example, but has made it more difficult to change things once > the harm has become evident. I won't call 1989 the "good old days" > but at that time we had to have the FCC test a computer and if it > passed, it by golly PASSED. Now, manufacturers self-certify, and if > assembling from parts that achieved self certification, often slap a > label on as "assembled with" without concern for actual results. > This isn't BPL/PLC, but an example nevertheless. I will refrain for > the sake of the forum from going into the politics! > But I'm willing to say "been there done that!" and defend it, too. > Cortland Richmond > KA5S > Wang Labs (FCC/EU standards, TEMPEST) > DEC (contract TEMPEST) > Tandy Computers (FCC. EU) > AST Research (FCC, EU) > DSC Communications/Alcatel USA (GR-1089) > Medtronic Physio-Control (contract) (IEC 610000-4) > Smiths Aerospace/GE AViation (MIL STD 461, DO-160 etc,) > > ----- Original Message ----- > From: Mark Gandler<mailto:[email protected]> > To: [email protected]<mailto:[email protected]>;[email protected]< > mailto:[email protected]> > Sent: 5/19/2010 3:11:05 PM > Subject: RE: [PSES] CE Standard for Power Lines data Transmission System > wow, someone is HAMgry. Apology (when became available) would be > accepted. Lesson learned: "don't touch the man's ham". As I > mentioned before, as long as I can use your services in case of > emergency, I will be "ham's the word" or is it hum or mum, can't > quite remember. I hope the emc-pstc people will cut this discussion > short, I am getting "num". > ________________________________ > To: [email protected] > CC: [email protected] > Date: Wed, 19 May 2010 07:45:37 -0700 > Subject: Re: [PSES] CE Standard for Power Lines data Transmission System > From: [email protected] > Yes, it was a bit sharp. > On Wed, 19 May 2010 07:31:58 -0600 "Grasso, Charles" <Charles. > [email protected]<mailto:[email protected]>> writes: > Hold on Orin. Your last statement "Now shut up about the hams" is > out of line. This forum is (or supposed to be) > a friendly exchange of ideas. > Best Regards > Charles Grasso > ________________________________ > From: [email protected] [mailto:[email protected]] On Behalf Of o. laney > Sent: Tuesday, May 18, 2010 8:19 PM > To: [email protected] > Cc: [email protected] > Subject: Re: [PSES] CE Standard for Power Lines data Transmission System > Why do you assert that government users are not concerned? They are > very concerned, do studies, publish papers, and hold conferences. > However, public safety and defense concerns are not usually for > public consumption. My government contacts who conduct field > studies tell me that even NATO is concerned, the problem being that > the aggregate transmitting power on miles of radiating lines is > enough to be detectable after ionospheric bounce. We're talking > very large distances. > By any measure, BPL/PLC in the HF band is dung. BPL was conceived > by businessmen who don't know coax from garden hose, implemented > politically on the business side and by engineers they pay but don't > listen to on the technical side. Among other critical services in > the HF band there are long distance aircraft and maritime > communications, research telemetry, and all sorts of other things > that depend on reliable reception of weak signals. These are > scattered all through the HF band, and notching the hams is > politically expedient but no protection for these other users. > Believe me, the FCC is in the loop on this, but Michael Powell > rammed approval down the throats of staff. He's a lawyer, and > science be damned. > Now shut up about the hams. They have sound science behind them and > the technical problems cannot be finessed away. You do understand, > I hope, that notching means in-band energy reduction, but not > elimination. It helps but is not a panacea by any stretch of the > imagination. And yes, the hams are well regarded for their ability > to provide emergency communications. The amateur service is > predicated on such capability along with advancement of the > technical art, and not simply as an indulgence for hobbyists. > Orin Laney > > On Tue, 18 May 2010 15:59:43 -0500 Mark Gandler <[email protected]< > mailto:[email protected]>> writes: > Unfortunately, hams complaining about anything and everything > related to BPL, even small home Ethernet adapters, which are > notched, signals are lower power and they get significantly reduced > power beyond any circuit breaker. And those products are easier > targets, as there are more of them around, they are on store shelves > and fall under EMC Directive. > and why are the majority of the complaints come from UK? BPL has > much higher sales in Germany and France. > As well we are not getting any complaints from any government operations. > If hams will be the only ones with communication devices left during > the disaster, please make sure to post your addresses, so we can all > flock to it, I am not joking. > ________________________________ > From: [email protected] > To: [email protected]; - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. To post a message to the list, send your > e-mail to <[email protected]<mailto:[email protected]>> > All emc-pstc postings are archived and searchable on the web at > http://www.ieeecommunities.org/emc-pstc > Graphics (in well-used formats), large files, etc. can be posted to that URL. > Website: http://www.ieee-pses.org/ > Instructions: http://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > For help, send mail to the list administrators: > Scott Douglas <[email protected]<mailto:[email protected]>> > Mike Cantwell <[email protected]<mailto:[email protected]>> > For policy questions, send mail to: > Jim Bacher <[email protected]<mailto:[email protected]>> > David Heald <[email protected]<mailto:[email protected]>> > > ________________________________ > Hotmail has tools for the New Busy. Search, chat and e-mail from > your inbox. Learn more.<http://www.windowslive. > com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_1 > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. To post a message to the list, send your > e-mail to <[email protected]<mailto:[email protected]>> > All emc-pstc postings are archived and searchable on the web at > http://www.ieeecommunities.org/emc-pstc > Graphics (in well-used formats), large files, etc. can be posted to that URL. > Website: http://www.ieee-pses.org/ > Instructions: http://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > For help, send mail to the list administrators: > Scott Douglas <[email protected]<mailto:[email protected]>> > Mike Cantwell <[email protected]<mailto:[email protected]>> > For policy questions, send mail to: > Jim Bacher <[email protected]<mailto:[email protected]>> > David Heald <[email protected]<mailto:[email protected]>> > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. To post a message to the list, send your > e-mail to <[email protected]<mailto:[email protected]>> > All emc-pstc postings are archived and searchable on the web at > http://www.ieeecommunities.org/emc-pstc > Graphics (in well-used formats), large files, etc. can be posted to that URL. > Website: http://www.ieee-pses.org/ > Instructions: http://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > For help, send mail to the list administrators: > Scott Douglas <[email protected]<mailto:[email protected]>> > Mike Cantwell <[email protected]<mailto:[email protected]>> > For policy questions, send mail to: > Jim Bacher <[email protected]<mailto:[email protected]>> > David Heald <[email protected]<mailto:[email protected]>> > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. To post a message to the list, send your > e-mail to <[email protected]<mailto:[email protected]>> > All emc-pstc postings are archived and searchable on the web at > http://www.ieeecommunities.org/emc-pstc > Graphics (in well-used formats), large files, etc. can be posted to that URL. > Website: http://www.ieee-pses.org/ > Instructions: http://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > For help, send mail to the list administrators: > Scott Douglas <[email protected]<mailto:[email protected]>> > Mike Cantwell <[email protected]<mailto:[email protected]>> > For policy questions, send mail to: > Jim Bacher <[email protected]<mailto:[email protected]>> > David Heald <[email protected]<mailto:[email protected]>> > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. To post a message to the list, send your > e-mail to <[email protected]> > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc > Graphics (in well-used formats), large files, etc. can be posted to that URL. > Website: http://www.ieee-pses.org/ > Instructions: http://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > For policy questions, send mail to: > Jim Bacher: <[email protected]> > David Heald: <[email protected]> > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. To post a message to the list, send your > e-mail to <[email protected]> > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc > Graphics (in well-used formats), large files, etc. can be posted to that URL. > Website: http://www.ieee-pses.org/ > Instructions: http://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > For policy questions, send mail to: > Jim Bacher: <[email protected]> > David Heald: <[email protected]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
