> I was studying the schematics of tag readers and it struck me odd that
> there is
> no measure whatsoever to reduce harmonic radiation in most of them, in
> some, one
> can see a lame attempt at tuning the coil with a capacitor. These devices
> will
> put upwards of 10 Watts into the 'air' without any bandwidth and harmonic
> limiting ?! While I know that the frequencies used are reserved for this
> use
> (and so are their harmonics - excepting 125 kHz which will be all over
> everything up to a few MHz at least - not that anyone would notice, due to
> the
> amount of smpsu's using similar frequencies), I do not remember seeing any
> waiver on harmonic radiation for these devices ? So what gives ? Is their
> harmonic radiation tolerated in the interest of better and more
> inexpensive Big
> Brothering ?
>
> a discussion is welcome, thanks,
> Peter P.
>


http://sujan.hallikainen.org/FCC/FccRules/2008/15/240/ requires emissions
outside the 433.5 to 434.5MHz band meet the requirements of 15.209
(http://sujan.hallikainen.org/FCC/FccRules/2008/15/209). That's all I
found on a text search on RFID. Regarding 125kHz RFID (which I've worked
with for a cow thermometer - see http://www.gla-ag.com), it appears in the
US, FCC rule 15.209 (above) is the limiting factor. There are other rules
for specific frequency ranges, but they only apply down to 160kHz.

Harold

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