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<H1 align=left>Power Line Communications on agenda at ITU</H1>
<P align=left><FONT face=Tahoma>ITU Working Parties 1A and 1B will meet in
Geneva between June 21 and 28. A major item of discussion will be protection of
radio services from interference from <STRONG>Power Line Communications</STRONG>
(PLC) also known as PLT or BPL. </FONT></P>
<P><FONT face=Tahoma><STRONG>IARU</STRONG> has already contributed to the ITU-R
report SM2158 “ Impact of power line telecommunication systems on
radiocommunication systems operating in the LF, MF, HF and VHF bands below 80
MHz“ where the acceptable criteria for degradation of the HF radio noise floor
caused by PLT is defined as being 0.5dB. Work in WP1A will concentrate on
the protection of radio services from the effects of PLT in range from 80 to
200MHz. </FONT></P>
<P><FONT face=Tahoma>The IARU delegate to SG1 and its working parties is
<STRONG>Peter Chadwick G3RZP</STRONG>: three input contributions have been
prepared for this meeting. One of these is a report on the effects of
intermodulation in power supplies causing the amateur band frequency notches in
the PLT spectrum to be degraded: this report has been prepared from the work by
<STRONG>Richard Marshall, G3SBA</STRONG> published in the RSGB RadCom magazine,
and also points out the difficulty such effects could have on the PLT system
itself. </FONT></P>
<P><FONT face=Tahoma>A further input establishes the protection criteria for
amateur stations operating in the 2 metre band: <STRONG>Ian White,
GM3SEK</STRONG> contributed to this input, and it is considered that the amateur
and amateur satellite services require protection such that PLT interference
does not exceed -45dB m V/m in the main lobe of the antenna, with a separation
between antenna and the PLT installation being at least 10 metres. </FONT></P>
<P><FONT face=Tahoma>The third input is of a more general character showing that
there are a number of non-amateur services that could suffer interference from
PLT or its harmonics, such applications including social alarms for the elderly,
pagers, medical implant telemetry, as well as broadcast, and when aggregation of
radiation is concerned, aircraft navigation and communications. When the
differences in range between PLT and mains leads and the social alarms and
medical implant ‘base’ stations etc., are taken into account, the acceptable
levels of radiation to protect the amateur services are of the same order as
those needed to protect these other services.<BR></FONT></P></BODY></HTML>