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Re: LF: More QRM ?

To: [email protected]
Subject: Re: LF: More QRM ?
From: "Hans-Joachim Brandt" <[email protected]>
Date: Wed, 11 Apr 2001 01:58:17 +0200
References: <[email protected]>
Reply-to: [email protected]
Sender: <[email protected]>
Dear all,

in order to convert just words into figures I feel it necessary to describe the situation in Germany more in detail.
The german NB30 standard has been rejected by all german radio users and
radio equipment manufacturers since it has been proposed. For those who know the
british MPT 1570 the problem is that NB30 allows interfering fieldstrengths 20
dB higher. But even the resistance of the german broadcasters could not prevent
the adoption of the NB30 standard. The declared aim of the german government
and the upper house of parliament has been to give "modern telecommunications
technologies" a chance. The CENELEC standard on CATV systems covering 5 MHz to
3000 MHz has also been aligned to the NB30 limits earlier, at least in the HF
and VHF-UHF range. (NB is simply a german abbreviation for Nutzungsbestimmung =
operational condition or regulation. There are other NB numbers within the
german frequency allocation table.)
A radio amateur living in a house in which cables are operated under the
conditions of the NB30 and having a half wave antenna 10 meters away from his
house will have to expect the following calculated S meter readings:

Band, MHz       1,8             3,6             7       14      21      28
NB30 dB(muV/m) 37,8 35,1 32,6 29,9 28,4 27,3
S-Meter         S9 +12 dB       S9 +3 dB        S8      S6-7    S5-6    S5

I hope the table will be delivered in the same order in which I have typed it.

The second line gives the interfering fieldstrength permitted by NB30. The situation is bad, especially for QRPers. But all efforts of DARC to prevent such a decision were in vain.
Regarding the frequency depending levels of the NB30 it must be stated that it
will allow VDSL and telecommunication over CATV, but only low-level PLC.
High-level PLC producing interfering fieldstrengths of 80 dB(muV/m) or even
more, is not permitted, this being the reason for the SIEMENS company to leave
the PLC business some weeks ago. ASCOM (who now will supply power line companies
which formerly had decided to use SIEMENS equipment) has claimed in a newspaper
interview that NB30 low-level PLC would not enable a bit failure rate
sufficiently low for 75% of all mains outlets. Therefore PLC becomes more costy,
less dependable, repeaters are needed etc. The real winners of the german
government decision seem to be those companies which will operate VDSL over
telephone lines because they will have no (or only few) problems to meet the
NB30 radiation levels. We know that in the U. K. the MPT 1570 (the range 1.6 to
30 MHz, from December 1999) is also under pressure because its low levels even
do not permit VDSL operation, but offers much better protection for radio
The European Commission is also in favour of PLC, because a network independant
of the telephone net could be used. But after the PLC Forum had conducted a PLC
workshop before the Commission, where strong opposition by radio users had been
presented, the Commission is said to be at least unsafe whom to believe. But
basically the Commission still thinks that a compromise with radio users should
be possible, and still hopes that a standard would solve all problems.
For the time being, german radio amateurs hope, of course, that this german
example will not be copied by other nations and that european standardization
(especially the way being carried out in CEPT SE35) will result in lower
interference radiation levels, for the benefit of radio services. And we also
hope that the german administration will be able to effectively control the NB30
limits throughout the country; otherwise a chaos would develop, no question.

Sorry to report such a situation here over the server.

73 Ha-Jo, DJ1ZB

Andre' Kesteloot schrieb:
Power lines win German support
By Reuters
March 30, 2001, 11:05 a.m. PT
 FRANKFURT--Germany's Bundesrat upper house of parliament on Friday
regulatory hurdles for the so-called power-line technology for fast
access via electricity lines. A statement issued by the economics
in Berlin said three laws setting out the conditions for power-line
operations had been approved, clearing the way for nationwide
in the 16 states in due course.

The move gives power line the chance of competing with other established

communications channels such as cable television and telephone networks.

Analysts say that by delivering high-speed Internet connections through
residential wall sockets, utilities could break the phone companies'
grip on
Internet access while also offsetting recent losses due to shrinking
power margins.

Story Copyright C 2001 Reuters Limited. All rights reserved.

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