Radio interferance and electric fencing

IrishKnight

I think this is more of a physics question but feel free to move it as needs be.

I live on a farm that uses electric fencing. If there is a short on the line which can the caused for example by a small branch touching the wire. This produces a clicking sound, about once per second.

When a short occurs, we often get the same clicking sound on our radio and something even on the TV.

So my question to you, explain to me why this happens...

Michael Collins

The most plausible explanation I can think of is this:

The electric fence probably works on a back EMF principle, so every so often it puts very high voltage on the line, a few thousand volts most likely. If you touch the fence in between the pulses, you actually won't get a shock. (Back EMF works by building up a magnetic field and then suddenly breaking it -> high voltage or 'EMF' spike). Now if there's something shorting the line, you'll also have a current spike, it won't be very much since electric fences operate at a low current (to avoid electrocuting what/whoever touches it). But nonetheless what you have now is a long piece of wire (the fence) carrying a current - this is exactly how you make an antenna! So this sends out a pulse of electromagnetic energy over a large range of frequencies, which naturally interferes with your TV and Radio.

I'm assuming that's there's no direct connection from your TV / Radio setup to your fencer in the above i.e. that's it's either battery operated or isolated some how. If there is there could be another explanation.

IrishKnight

Makes sence. Thanks!