[time-nuts] EMI and CE certification

[Jim Lux]

On 5/11/15 12:52 PM, Adrian Godwin wrote:
> Is it driven as  an inductive loop? That might put it under different
> regulations.
> On 11 May 2015 17:47, "Chuck Harris" <cfharris at erols.com> wrote:
>
>> Yes, but in the case of the lawnmower fence, and the
>> invisible dog fence, the transmitter drives the fence
>> as an antenna.
>>
>> In the US, the antenna size for "free bands" is seriously
>> limited.  As an example, the so called "Lowfer" band at
>> 136KHz is limited to antennas no larger than 15m in length.
>>
>> And, that is one of the larger limitations.
>>
>> 15m would encircle only a very small lawn.
>>
>> OBTW, I realized on reading my post below, that I was very
>> unclear on what could "be foiled."  I meant that the
>> operating permission for the lawnmower system could probably
>> be foiled by looking into the maximum antenna lengths for
>> unlicensed services of this sort, in this frequency range.
>>
>> I would quite imagine that any certification they may have
>> is for the transmitter and receiver, without an antenna.
>>



The US FCC Part 15 limit is probably 2400/f(kHz) uV/m field strength at 
300m distance.

It's probably pretty easy to meet that.


https://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf