* Posts by Nige_C

1 post • joined 12 Aug 2010

Documents show CAA fears over powerline networks


Regarding PLT (PLN)

So that there is no ambiguity, particularly aimed at the first few comments, the article refers to powerline network adapters, of the likes supplied by BT with its BT Vision broadband TV package and commercially available from most electrical retailers, which are effectively modems which use the internal electrical mains supply wiring of a building.

I would also like to comment that I was one of the delegates invited to and participated in the meeting at Ofcom to which the article refers and confirm that the article accurately sums up the the two hour meeting during which we were allowed 30 minutes to question PA Consulting and roughly 50 minutes to question Ofcom.

Ofcom agreed the technical content of the report but stated that the report did not change Ofcom's regulatory position on PLT which remains in line with their September 2009 Statement and the June 2010 "addendum".

Do not think for one moment that the article is sensationalist, some of the UK's most respected RF and EMC engineers were present at the Ofcom meeting and they did not hold back on their professional opinion as to the seriousness of allowing this technology to continue. The CAA made a protracted and valid input to the meeting in which they expressed a deep concern for the implications for the future if large numbers of the devices are put into service.

The mitigation technique proposed by the PLT industry and heavily relied upon by PA Consulting in their report was studied prior to the meeting and determined that instead of being a power reduction scheme to reduce interference, it will in fact have the ability to increase the power level used by the modems by a further 15dB which, taking the UKAS accredited test results of the Comtrend devices used by BT in BT Vision, which are already 36dB above the EN55022 limit, adding a further 15dB to this will mean in reality that the emission level will be the same as 126 thousand barely-legal devices all plugged into the same socket and operating at the same time.

I realise that the technology is convenient - I used it myself, once, until I realised the consequences of my actions. We must also remember that Ofcom, far from being an independent regulator are simply marionettes dancing to the tune being played by DG Enterprise, who were also present at the UK spectrum stakeholder meeting, despite being neither a UK spectrum stakeholder nor a UK organisation - but had the time to quote their "no barrier to free trade" mantra...



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