ARRL

Interference From BPL Systems

 

FCC Position Statements About Interference

 

Most of the FCC Commissioners have said some pretty significant things about BPL interference. These should serve as the model for the way the FCC will handle interference complaints.

 

Formal Complaints about BPL Interference

 

Contrary to the claims by the BPL industry, most BPL deployments have resulted in serious interference problems.  Although some have been corrected, others have not, and the pattern of the initial installations having interference problems, followed by the rounds of denials and allegations that complaints are somehow "frivolous" continues worldwide.

 

Australia:

ACMA Measures BPL Emissions at Mt Beauty

South Africa:

Report on Investigation of R F I caused by PLC system at Rooiwal Township
"On Saturday 22 July 2006 at approximately 17:00 Paul Ras ZS6PR, Adanus Seymore ZS6AU and Marten du Preez ZS6ZY drove to the Rooiwal Township to investigate the RFI caused by the PLC system which has been installed in the Township. . . The initial observation was done on 3,640 MHz . As we entered the Township the interference increased to 9 +20 dB and remained at that level as we drove around in the Township. Observations were made on the corner of 4th and 8th Streets and the S meter still registered 9+20 dB. . . We drove off and observed that the interference decreased to about S2 at a distance of 300 meters from the entrance of the Township and thereafter no interference were heard. From the above report it can be concluded that a radio amateur living in the Rooiwal Township and having installed well designed antennas for HF operation will not be able to communicate on 80 and 40 M. " An audio recording of the interference in Rooiwal shows strong noise. Submitted by: Marten du Preez ZS6ZY 

 

United States: 

Here are interference reports filed with the FCC.

 

BPL Measurements and Studies in the US (ARRL)

 

ARRL Home Page:
ARRL EMC Committee page:

 

ARRL FCC Filings:

 

ARRL, The National Association for Amateur Radio:

Comment: et03-104 (files broken down individually for easy loading)

Section
ARRL Comments on ET 03-104, the FCC Notice of Inquiry on Broadband Over Power Line
BPL Feed Method Analysis
Fields Near Large Radiators
Power Lines As Antennas
Calculated Impact of BPL Signals on Amateur Radio
Antenna Models Submitted With ARRL Filing

 

Comment: http://gullfoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6514284573

Reply: http://gullfoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6514683402

Exhibit A: Description of the ARRL video recording of BPL noise in trial areas http://gullfoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6514683403

Exhibit B: Analysis of BPL conducted signal levels compared to present FCC conducted emissions limits :http://gullfoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6514683404

Exhibit C: VOACAP propagation analysis of the effect of Part-15 signal levels on worldwide communication http://gullfoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6514683434

 

Video link referenced in Exhibit A:

Antenna models references in ARRL comments: http://www.arrl.org/~ehare/rfi/plc/bplant.zip

 

Calculated Impact of PLC on Stations Operating in the Amateur Radio Service
Summary: This is presentation that Ed Hare, W1RFI, ARRL Laboratory Manager, gave at the November 2002 meeting of the IEEE C63 EMC standards committee. It contains a tutorial on PLC, calculations on the interference potential from access PLC and a summary of what ARRL believes is necessary to prevent interference from carrier-current devices. ARRL's calculations estimate that the ambient noise level near PLC systems could increase as much as 70 dB.
Author: ARRL, Ed Hare, W1RFI@arrl.org

 

HomePlug and ARRL Joint Test Report
Summary: HomePlug (Internet: http://www.homeplug.org/) is an industry of manufacturers of in-building PLC systems designed to network computers within a building. This describes the testing that ARRL did in late 2000 with HomePlug to help establish the spectral masks (notches) that HomePlug included in its product specification to help protect Amateur Radio from harmful interference.
Author: ARRL, Ed Hare, W1RFI@arrl.org


BPL Measurements and Studies in Other Countries

 

Japan

 

Finland

 

The Netherlands

 

Norway

 

Great Britain

 

Poland

 

Germany

 

European General Information

 


 

Amateur Radio Interference Studies -- Other Broadband Technologies

 

Home Phone Networking Alliance Testing -- Version 1 (ARRL)
Internet: http://www.arrl.org/arrl-testing-of-home-phone-network-card
Summary: These are the test results from testing of the Home Phone Networking Alliance (HPNA) Version 1 product. The tests were performed by Ed Hare, W1RFI, at his home station. This product meets FCC limits, but the tests indicate that it had a significant interference potential to nearby amateur radio operation. Version 1 HNPA devices are no longer in production. Version 2 includes a spectral mask to protect sensitive Amateur Radio HF reception.
Author: ARRL, Ed Hare, W1RFI@arrl.org

 

VDSL Testing (ARRL)
Internet:
Summary: This paper describes testing done by Ed Hare, W1RFI, in Phoenix, AZ. He used a mobile HF receiver on 80 and 40 meters to drive through areas in Phoenix where VDSL was installed. These areas were all served by underground utility wiring. No significant RFI potential from this system was detected.
Author: ARRL, Ed Hare, W1RFI@arrl.org

 

VDSL-TIA Presentation -- 1999 - Operating Parameters of Typical HF US Amateur Stations - (ARRL)
Summary: This is a two-part presentation on VDSL given by Ed Hare, W1RFI, ARRL Laboratory Manager, at a 1999 meeting of the TIA T1E1.4 VDSL standards committee. It outlined the operating characteristics of Amateur Radio stations and the expected impact of VDSL systems on Amateur operation.
Author: ARRL, Ed Hare, W1RFI@arrl.org

 

VDSL-TIA Presentation -- 2002 -- Possible Impact of VDSL on Stations Operating In the Amateur Radio Service (ARRL)
Internet: http://www.arrl.org/files/file/Technology/tis/info/plc/vdsl-tia.ppt
Summary: This is a PowerPoint file of a presentation given by Ed Hare, W1RFI, ARRL Laboratory Manager, at a 2002 meeting of the TIA T1E1.4 VDSL standards committee. It reiterated some of the interference issues under consideration and presented calculations of the interference potential of VDSL systems.
Author: ARRL, Ed Hare, W1RFI@arrl.org

 

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Operating Parameters of Amateur Radio Stations:

 

 

 

These files describe the technical parameters for Amateur stations operating on the HF Amateur bands. They were authored by Zack Lau, W1VT, ARRL Senior Laboratory Engineer. 

 

Reference Circuit Information for the MF and HF Amateur Bands:

 

1.8 MHz

 

3.5 MHz

 

7.0 MHz

 

10.1 MHz

 

14.0 MHz

 

18.068 MHz

 

21.0 MHz

 

24.9 MHz

 

28.0 MHz

 

Estimated Field Strength from Amateur Radio Stations -- ARRL #1
Internet: http://www.arrl.org/estimated-field-strength-from-amateur-radio-stations-arrl-1
Summary: This paper, presented at a 1999 meeting of the T1E1.4 VDSL standards committee, outlines the expected field strength and ambient noise level of typical HF amateur stations. Amateur stations operate with very sensitive systems that can be degraded by local noise sources. They also can radiate some relatively strong fields at heights typical of telephone-wiring installations. These factors must be considered when evaluating the compatibility of high-speed digital systems that may be installed in residential areas. Several papers previously presented indicate that VDSL technology may be compatible with the Amateur Radio Service, but just compatible. These additional data indicate that those conclusions need to be reconsidered and additional calculations made.
Author: ARRL, Ed Hare, W1RFI@arrl.org

 

Estimated Field Strength from Amateur Radio Stations -- EPA, Overbeck
Internet: http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/reports/asd9601/asd9601.pdf
Summary: This paper outlines measurements of the field strength from typical HF and VHF amateur stations.
Author: Bob Cleveland, rclevela@fcc.gov, Ed Mantiply, emantipl@fcc.gov

 

FCC RF-Exposure Regulations -- the Station Evaluation
Internet: http://www.arrl.org/news/rfsafety/eval/index.html
Summary: This article describes FCC OET Bulletin 65 Supplement B and tells hams how to use it to estimate the field strength near their stations to comply with the FCC regulations on RF exposure.
Author: ARRL, Ed Hare, W1RFI@arrl.org

 

FCC OET Bulletin 65 -- estimating RF exposure from radio transmitters (Internet)
Internet: http://www.fcc.gov/oet/info/documents/bulletins/#65
Summary: This paper outlines the ways that amateurs can calculate or measure the field strength from their stations. Typical field-strength levels are described.
Author: FCC

 

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Case History of Widespread Interference From Part-15 Carrier-Current Device:

 

Interference Case History from Wireless Modem Jacks
Internet: http://www.arrl.org/wireless-modem-and-telephone-jacks
Summary: This is a case history of severe interference to Amateur Radio from a device that had been Verified under FCC Part 15 to be in compliance with the rules. The manufacturer was very responsive and corrected the interference by redesigning the product not to use Amateur frequencies. The devices were deployed widely and the end user ultimately had to do a system-wide recall in the field. ARRL appreciates that those involved acted appropriately, but this serves as a good case history about the level and degree of interference that can come from devices that are at the current FCC limits, and of the costs to industry that can result if interference is not mitigated at a product's initial design. The model under discussion has not been in production for several years and the company's present products are not known to present any significant interference potential.
Author: ARRL, Ed Hare, W1RFI@arrl.org

 

Reply Comments of Aeronautical Radio, Inc:
Internet: http://gullfoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_document=6514683399
Summary: Report of interference from HF carrier-current device causing interference to HF aeronautical communications:

 

 

 

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Interference To BPL from Amateur Radio Operation:

 

Analysis by Ed Hare, W1RFI -- estimate
Internet: http://www.arrl.org/Interference-to-PLC-systems-from-Amateur-Radio-Operation
Summary: A free-space calculation the expected field strength from HF amateur stations.
Author: ARRL, Ed Hare, W1RFI@arrl.org

 

Links to operating parameters of Amateur Radio Stations

 

Return to "Quick Links" Section of This Document

 

Industry/Other Interference Studies:

To date, none of the numerous industry studies on BPL have contained any published information on harmful interference. The following studies and presentations are being used by the PLC industry to promote the technology.

 

This German Language paper published by the German Ministry of Economics and Labor, paints a less-than-rosy picture for BPL. A synopsis in English is included (see pages 15 to 18). This recommendation seeks to set limits that are about 30 to 50 dB lower than the FCC emissions limits. The levels they propose, typically about 15 dBuV/m at 3-meters measurement distance, would be - 5 dBuV/m if extrapolated to 30 meters using a 20 dB/decade extrapolation factor. This is at about the same levels that ARRL determined would be necessary to protect most radio reception near BPL systems. This study shows that the levels necessary to protect radio reception are many dB lower than any BPL emissions limits worldwide.

 

UPLC/ PLCA Joint Report to the FCC:
Internet: http://www.uplc.utc.org/file_depot/0-10000000/0-10000/7966/conman/Joint+Report+on+PLC.pdf
Summary: On Monday, March 4, 2003, the United PowerLine Council and the Power Line Communications Association filed a Joint Report to the Federal Communications Commission on the present state of the PLC industry as well as appropriate next steps for the Commission to encourage the technology's commercial deployment.
Authors: United Power Line Council and the Power Lines Communications Association

 

PALAS - Powerline as an Alternative Local AcceSs project reports:
Internet: http://palas.regiocom.net/reports.html
Summary: Multiple reports, including some discussion of field trials.
Authors: Multiple

 

NUON discontinues BPL test (Dutch)
Internet:
http://www.webwereld.nl/nieuws/14920.phtmlhttp://www.webwereld.nl/nieuws/14920.phtml
Summary: NUON in the Netherlands is not going to offer its digital services through the power lines any longer. It will stop its services in the beginning of July. They have determined that the technology is too limited and that it is still not commercially attractive to offer internet services through the power lines. NUON claims that the test they performed shows that it is possible to offer internet services on a small scale. However, the technology is not ready yet for a large scale applications. One of the biggest problems is that it is very susceptible to interference. The Telecom Agency of the Dutch Government has determined through measurements that signals are too strong and cause interference to radio communications.
Author: Webwereld

 

Current Situation on the Field Trials and Other Tests Performed in the Netherlands
Internet: http://www.agentschap-telecom.nl/informatie/plc/Position_NL_PLC_C..pdf
Summary: This is a letter sent by the Dutch Telecom Agency to the European Committee containing the test report/results of the NUON PLC test in Arnhem. This small field trial resulted in a specific complaint of harmful interference by an Amateur Radio operator. The levels measured at 3 meters distance from the radiating source are listed in table format. They concluded that estimates based on the balance of the lines are not a reliable way to predict field strength.
Author: Dutch Telecom Agency

 

Information on radiating properties of mains networks
Internet: http://www.agentschap-telecom.nl/informatie/plc/NL_versie 6_final.pdf
Summary: This paper describes measurments made of the radiating characteristics of a number of houses in Holland. In Europe, it is common to have 100 or more houses connected to transformer, with each house fed with close-spaced or twisted-pair electrical wiring. Under these circumstances, the wiring radiation effectiveness was measured at about a -30 dBi average. In the US, access PLC signals would have to be coupled past the transformers onto the medium-voltage distribution lines, which will radiate more efficiently than twisted pairs and house wiring. The report also describes the cumulative effects of multiple emitters propagated by skywave. According to this study, a PLC system with 4 emitters per square kilometer will have a skywave propagated signal of -23 to -52 dBuV/m to distant areas.
Author: Radio Communications Agency, Netherlands.

 

Information on radiating properties of mains networks
Internet: http://www.agentschap-telecom.nl/informatie/plc/JWG_input.pdf
Summary: This paper describes measurments made of the radiating characteristics of a number of houses in Holland. In Europe, it is common to have 100 or more houses connected to transformer, with each house fed with close-spaced or twisted-pair electrical wiring. Under these circumstances, the wiring radiation effectiveness was measured at about a -30 dBi average. In the US, access PLC signals would have to be coupled past the transformers onto the medium-voltage distribution lines, which will radiate more efficiently than twisted pairs and house wiring. The report also describes the cumulative effects of multiple emitters propagated by skywave. According to this study, a PLC system with 4 emitters per square kilometer will have a skywave propagated signal of -23 to -52 dBuV/m to distant areas.

 

Digital Radio Mondiale
DRM has a strong position statement, concerned that BPL will seriously impact the reception of digital shortwave broadcast signals.

 

Articles and Papers about BPL Interference


British Broadcasting Corporation (BBC)

The BBC has done a number of studies about how BPL will cause interference to short-wave broadcast reception. The following BBC papers outline the findings of this international broadcaster:
WHP067 The effects of power-line telecommunications on broadcast reception: brief trial in Crieff 
WHP055 Do EMC limits protect broadcasting as intended? 
WHP063 How best to protect radio services as intended? 
WHP004 Cumulative effects of distributed interferers 
WHP012 AM broadcasting and emissions from xDSL/PLT/etc
WHP013 Emission limits: A new proposal based on a limited increase in the noise floor
WHP079 Calculation of the field strength of an interfering signal to produce 3 dB reduction of 46 dB4W s/n ratio for a 15 kHz AF bandwidth FM link  

 

BPL in Germany

This German Language paper published by the German Ministry of Economics and Labor, paints a less-than-rosy picture for BPL. A synopsis in English is included (see pages 15 to 18). This recommendation seeks to set limits that are about 30 to 50 dB lower than the FCC emissions limits. The levels they propose, typically about 15 dBuV/m at 3-meters measurement distance, would be - 5 dBuV/m if extrapolated to 30 meters using a 20 dB/decade extrapolation factor. This is at about the same levels that ARRL determined would be necessary to protect most radio reception near BPL systems. This study shows that the levels necessary to protect radio reception are many dB lower than any BPL emissions limits worldwide.

 

Interferences instead of shortwave broadcast
Listening to shortwave broadcast in parts of the city of Mannheim, Germany is almost impossible. This article documents that interference and the actions of German shortwave listeners and amateur operators to get this interference corrected.

 

Broadband Over Power-Line, A Mid-Term Grade

by: Carol Arneson,-Senior Manager, Virchow, Krause & Company, LLP
Robert Herbst, Senior Manager, Virchow, Krause & Company, LLP

Interference is among the many issues covered by this financial and technical analysis of BPL. The analysts note: "Technical Performance: D - The interference issue has not been completely addressed. It seems that many of the pilots would rather ignore the question rather than address the question directly. For example, Alliant Energy prematurely ended its BPL trial in Cedar Falls, Iowa. When the trial began, it was one of the most cooperative between amateur radio and the electric industry. However, interference issues sparked the American Radio Relay League (ARRL) to file a formal complaint with the FCC. Shortly afterwards, the trial was ended. We believe that there are ways to address the interference issues, but the BPL industry has not been forthcoming, nor proposed cost-effective solutions."

 

Power Line Communication at Fribourg

This study of an access BPL system in Switzerland was conducted by Swiss Regulators (OFCOM http://www.ofcom.ch). It concluded that at frequencies above 10MHz BPL interference clearly is the predominant cause for interference. Furthermore it has been shown, that the limit of the German standard NB30 is exceeded at all frequencies of interest between 2.4 MHz and 25.4 MHz at urban areas. The study is available only in French and only in pdf format.

 

Power Line Communication at Solothurn

 

This study of a HomePlug in-building BPL installation was conducted by Swiss Regulators (OFCOM http://www.ofcom.ch). Although HomePlug has often been cited as having solved the interference problem, OFCOM determined that "the statistical interference level emitted inside buildings is significant across the entire frequency band concerned (4.49 - 20.7 MHz), except in the amateur radio bands. The level reached is such that it appreciably exceeds the limits specified in the German NB30 regulations. The results also show that reception of high frequency radio signals is difficult or even impossible in the coverage area of the modem. The results permit the hypothesis to be made that this equipment is not in conformity with the essential requirements of the applicable European directives relating to EMC and that a particular effort should be made by the HomePlug consortium to produce a more appropriate standard."