LF: Inductive short range devices - the end of LF radio?

[Markus Vester <markusvester@aol.com>]

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 in https://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)