According to a senior government adviser, a simple way of reducing the problem is making sure there’s no plant material touching live wires.
“Electric fences need to be properly designed, installed and maintained,” says Ministry of Economic Development telecomms policy adviser Brian Johns. That means eliminating short circuits between fences and the ground.
Johns is part of a working group of representatives of the government, Telecom, Federated Farmers and fence manufacturers. The group is embarking on an 18-month promotional campaign aimed at helping farmers limit interference.
Johns says the effect comes about as electric fence voltage leaks into the ground, creating spikes on phone lines within range. Exactly how far the effect can spread depends on the voltage, but it may travel a kilometre or more.
Short circuits can be caused by wires touching the ground or being overgrown by grass or other foliage.
Federated Farmers policy manager John Pask says the working group wants to show farmers how to tackle the problem without the government having to resort to some form or regulation.
“We’re trying to educate farmers about solutions they can readily implement.”
If an electric fence is shorting, in can interfere not just with the the owner’s phone lines but those of neighbours’ as well, he says.
Johns says interference with dial-up internet connections commonly cuts data transfer speeds by 50%. Electric fences aren’t the only cause of interference; line noise, which is a factor of distance from a telephone exchange, is another problem.
“Some modems have better ability to work in the presence of noise than others. Cheaper, less robust coding schemes cope less well,” he says.
Aside from avoiding short circuits and using good quality modems, farmers should also keep electric fences and phones as far apart as possible, Johns says.
Guidelines on limiting the problem are being prepared, says Johns, and, if followed, the working group anticipates “significant improvements can be made”.