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" <cfhar...@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
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