Broadband - Business, Innovation and Skills Committee Contents

Memorandum submitted by the Radio Society of Great Britain


  The RSGB supports the ideal of broadband availability to all households, however, the membership of the RSGB and Radio Users in general are concerned with aspects of some particular technologies which are being used to implement broadband provisions in the United Kingdom.

  Our submission will highlight the inappropriate use of particular technology, such as PLT, which impinges on the High Frequency spectrum between 1-30MHz.


  The Radio Society of Great Britain represents Radio Amateurs, and Shortwave Listeners in the United Kingdom. With a membership of over 25,000, it is the voice of nearly half of the licensed radio transmitting stations in the UK.

  The RSGB is well represented within the International Amateur Radio Union (IARU), and our President is a key Committee Chairman within the International Telecommunication Union (ITU).

  The Society attends and contributes to the Committee working of BSI, CISPR, ITU and ETSI.


  Contrary to common belief the use of the HF spectrum is as full and busy as ever. The Broadcasters, the Military, Commercial Users and Radio Amateurs fight for primary use of segments of the spectrum at the World Administrative Radio Conference held every four years. The committee should be aware of the renewed interest from the broadcasters wishing to promote Digital Radio Mondiale Services.

  The importance of Amateur Radio as a back-up emergency service was especially highlighted by the catastrophic effects of the Asian tsunami and earthquakes. Many countries in the Pacific region acknowledge the importance of well-trained HF radio enthusiasts in emergency situations. Even with a highly developed infrastructure such as existed in New York, Amateur Radio was highly praise by President Bush for its contribution following the World Trade Centre disaster. In that case almost all Wire-Line and Cellular communication failed for several days. Amateur Radio was as ever ready, it was identified as the emergency response service that worked most effectively.

  Commercial radio users are returning to the HF spectrum because it offers a cost effective alternative to the digital satellite services offered by organisations like INMARSAT. HF radio is used by ships at sea, when out of range of VHF Coast Stations, and airline operators for aircraft flying in the mid-Atlantic, and the very long trans-Pacific routes.

  There are strong and compelling arguments for the preservation of a low ambient noise floor in the HF Spectrum.

  There are many pseudo-Government users, Civil Aviation Authority, Maritime Communications Agency, and even direct Government users, who express concerns regarding the pollution of the spectrum. They do not express these concerns publicly for fear of causing public alarm. The committee should have no doubts about the concerns however. There exist many technical papers expressing these concerns for such quarters as NATO (see note 2), and broadcasters.

  We would urge the committee not to overlook the social impact of Short Wave listening in our multi-cultural society. Many SW listeners are tuned-in on a regular basis to the radio stations abroad for news from their "home" countries. This has become particularly important with the enlargement of the EU, and whilst the internet provides a link for the more affluent, as this inquiry make clear, broadband is not yet available for all.


  The HF spectrum up to 30MHz is a precious resource which needs to be protected.

  The ITU recognised this important tenent in the early years of radio, and put in place measures intended to protect the spectrum for use in Broadcasting, and worldwide radio communication. The Comit

 international sp

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lectriques (CISPR) was formed in 1934 to establish standards for the control of emissions to and from electrical apparatus, which might impact the radio spectrum.

  The work of CISPR continues, with much of its work now being focused on the impact of digital technology.

  Digital Revolution has had a positive impact on communication with improvements in signal quality, more choice for the consumer, and in the near future a considerable reduction in power usage at the transmitter sites. Most of the applications of technology have had a welcomed and desirable effect.

  However, an inappropriate use of technology can be cited for Power Line Communication (also known as Power Line Telecommunications) PLC/PLT.

  CISPR has not been able to agree revision of the existing standards, which would accommodate PLT, and maintain the protection to radio services.


  This technology is available in two forms, Access PLT providing communication to and from the home, and in-Home PLT for communications entirely within the home. Fortunately all trials of Access PLT in the United Kingdom have been closed, and except for some specialised applications in tower-block apartments, there does not appear to be an appetite for roll-out of this technology at present.

  In-Home PLT has however become a consumer product, with many manufacturers offering Power Line Adapter, which provide communication between computers, TV receivers and potentially any other PLA equipped electrical appliances within a household.

  Both of these technologies cause interference to Radio Users in the HF Spectrum.

  See note 1

  The ITU has stated its position, quite clearly. It regards the technology as an unintentional radiator, and has placed a requirement on international standards makers, "that existing standards should not be changed or modified in order to permit PLT, except that any change shall provide the same level of protection for radio services".


  We wish to ensure that the committee understand that all existing PLT devices, whether they be for "access" or "in-Home" usage do not meet the internationally agreed emissions standards. In fact most exceed the limits set by 30dB (1,000 times).

  In order to placate the Radio Amateurs worldwide, mitigation measures have been put in place, and to try to placate Short Wave listeners some additional mitigation techniques have been proposed.

  The fact remains however, that the established limits will be exceeded where the mitigation measures do not apply. Furthermore, the Society, and many other Radio Users doubt the value of the proposed mitigation measures.

Interference and its impact

  Any egress of signal energy for PLT systems may be undesirable to a nearby listener, and the aggregation of signals from many millions of these devices will raise the ambient noise floor on a worldwide scale.

  Various reports from authorative sources have shown that the noise floor will rise by between 10dB to 15dB. See note 2 and 3.

  Since a radio user may be operating on very weak signals, this could mean the difference between successful communication, and none at all. The same applies to a short wave listener. See note 4.

  We draw to the attention of the committee, that whilst radio users accept a signal to noise margin of 10DB as being acceptable, PLT systems are set-up to have a massive headroom margin of 30dB.

  In the United Kingdom over 190 cases of interference have been reported to the Regulator (Ofcom) and of those over 120 have been remedied by removal of the interference source, a PLT modem.

  We would like the committee to make note of the fact that radio communications is the subject of an 11 year sun-spot-cycle. At the present (2009), we are just beginning to emerge from a period of extremely poor propagation of signal around the world. By 2014 communication will have recovered, and it will be possible to communicate with a very minimum of transmitted signal power. It is at this stage that the severity of egress from PLT systems into the HF spectrum will become evident.

Immunity Issues

  PLT can provide point to point communication on a sound but not altogether reliable basis. Whilst it is a cause of interference it is not particularly immune from interference to its operation. It is adversely affected by noise present on the mains network wiring.

  In-home PLT, which may be installed by the consumer, is particularly vulnerable to house wiring configuration. The sources of interference that adversely affect this technology are numerous. Nearby radio transmissions in the HF spectrum will frequently cause "blocking" of PLT signals.

  The committee should take the seriousness of diminution of throughput into account, as a factor in favour of alternative technology.

Recommendation to the Committee

  The RSGB strongly urge the Committee to consider and recommend the use of Fibre Optic and Wireless (Wi-Fi) systems in preference to PLT technology.

  The promise of Fibre to the Curb-side within the foreseeable future has already been made. The last hurdle (no longer the last mile); will be distribution into the home. It is our belief that this will be best accomplished by continuing the fibre, or by providing localised Wi-Fi access for user communities.

  BERR should work with and encourage Ofcom to release spectrum above 500MHz for this purpose, as part of the Digital Dividend.

  The RSGB recognise that the implementation of "Smart Grid" may require each and every household to be connected- although not necessarily on a broadband service. However the prospect of every one of 15 million households, each with an individual IP address raises the issue of aggregation of interference to a new height. We hope that the Committee will consider this.

  We urge the Committee to ensure that the undertaking given by Ofcom to investigate interference complaints is maintained. See Note 5.


(1)  ITU, Doc. 1/101-E and 1/102-E, and Doc. 1A/117-E, 1A/118-E

(2)  NATO Doc. RTO-TR-IST-050, AC/323(IST-050)TP/44, (ISBN 978-92-837-0069-2)

(3)  ITU, Doc. 1A/35-E

(4)  ECC Recommendation (05)04, Criteria for the Assessment of Radio Interference caused by Radiated Disturbance from Wire-Line Telecommunications Networks

(5)  Wire-Line_Event_09 PowerPoint presentation, hosted by DTI/Ofcom. See slide 20

October 2009

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