[time-nuts] lawnmower robots may be the end of VLF timekeeping

[Attila Kinali]

Moikka moi!

I first thought about taking this off-list, but then decided against
it because i think this topic is of general interest, not only to
ham radios (who are the first one to notice) and time-nuts, but also
to other, non-technical people.

On Sat, 09 May 2015 22:10:51 +0300
Esa Heikkinen <tn1ajb at nic.fi> wrote:

> Poul-Henning Kamp kirjoitti:
> 
> > I spent some time capturing some data today.
> > The measurements is from my $20 loop-antenna in the attic, which is
> > something like 8 meters up and 10 meters besides the lawn-mower loop:
> > 	http://phk.freebsd.dk/time/20150509.html
> 
> In the Finland that problem is even worse! For me it's called Savon 
> Voima, our local power company (but also many other power companies 
> around the Finland). They are using PLC based remote readable utility 
> meters. These meters communicate with power lines, using ancient 1200 
> bps. FSK using 83.2/93.6 kHz frequencies. Because the power grid is not 
> designed for this kind of communication, those frequencies will of 
> course leak all over the places.

[...]

> When this was reported to Finnish authority called Viestintävirasto 
> (it's Finnish version of FCC), they say that this doesn't matter - the 
> DCF77 is not "protected" in Finland (even when you can buy radio 
> controlled clocks from the shop).


This is outrageous! Someone in Finnland is not doing his job!
The frequency regulations do not protect single frequencies, but
frequency ranges and their use. The CEPT[1] reserves the 72-84kHz range
for radio navigation (beside others) and explicitly mentiones DCF77
as a big user. I am not sure where the according allowed emission levels
are (and currently i don't have access to the standard documents) and
it might very well be that the standards stop at 100kHz or 150kHz...
BUT! Devices are still not allowed to interfere with legitimate users
in any radio bands. If they do, then they are violating the EMI/EMC laws[2].

I have seen quite a few regulation authorities not enforcing the
established rules in recent years. Partially because it costs money
to make a device compliant (and thus getting pressure from industry)
and partially, because the times of crackling radio and TV sets are
over (and thus the imediate need isn't as obvious as it used to).
Yet, with the ever increasing number it becomes more and more important
that emissions are kept at the lowest level possible.

If your regulation authority does stupid things like the Finnish one,
then you should talk to your political reprentatives and tell them about it.
This is not a minor issue of just someone not being able to use his weird
toy, but an issue of whole cities not being able to use their alarm clocks
anymore! Not to talk about what happens when someones lawn mowner starts
interfering with his neighbors pacemaker... 


				Attila Kinali

[1] http://www.erodocdb.dk/Docs/doc98/official/pdf/ercrep025.pdf

[2] "'electromagnetic compatibility'means the ability of equipment
    to function satisfactorily in its electromagnetic environment
    without introducing intolerable electromagnetic disturbances to
    other equipment in that environment;"
	from European Directive 2004/108/EC


-- 
< _av500_> phd is easy
< _av500_> getting dsl is hard