Пара писем из RSGB рефлектора о перспективах LF.
Хотя может и не все так плохо.
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rsgb_lf_group@yahoogroups.co.uk, <markusvester@...> wrote :
A few weeks ago, the IARU EMC coordinator, Thilo Kootz, made me aware of an European directive "Decision 2006/771/EC on harmonisation of the radio spectrum for use by short-range devices...", see
http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=uriserv:OJ.L_.2013.334.01.0017.01.ENG This rule prescribes magnetic fieldstrength limits for short range devices, including inductive chargers in the 9 to 150 kHz frequency range (e.g. the "Ikea chargers" mentioned inhttps://uk.groups.yahoo.com/neo/groups/rsgb_lf_group/conversations/messages/4650 ). Thilo asked me about potential interference to LF amateurs and other services, and after some near-field calculations I came up with a paper:
http://df6nm.bplaced.net/LF/srd/LF_interference_from_inductive_SRDs.pdf The conclusions seem to be rather alarming: For an LF amateur in a typical suburban environment, the noise may go up by as much as 70 dB (!) if only one of the neighbours happens to operate a compliant inductive device on 136 kHz! As these devices will probably be deployed in large numbers, this may well be the end of receive possibilities for many of us.
I am hoping for increased awareness regarding this issue, amongst amateurs as well as other affected parties. Let us raise our voices, and try to use our affiliations to obtain some influence on political decisions, which have so far apparently been guided by economical interest alone.
All the best,
Markus (DF6NM)
Hi Markus,
Thank you very much for this complete and important paper. If interference is only affecting radio amateurs, authorities will usually let commercial and general public interests prevail over the interests of a few "nerds" hi (especially us LOWFERS). But in this paper, you make the case for the potential degradation of utility, navigation and timing functions as well and this should catch some interest, I hope.
I will make sure this paper will get to the attention of the Norwegian Radio Relay League and our National Communications Authority. I hope others will promote the paper as well within their national channels.
73, Robert
LA4ANA
