This may have nothing to do with Wifi, but i think this is a good place to start...

A few weeks ago a new thick black cable appeared under the overhead power cables running down the side of my property that feed the houses behind me. This new black cable has been run down the power pole on the street under the footpath which has been dug up. It leads from the power pole on the street, down a long driveway right beside my house to a pole that distributes the power connections to the houses around me. On that pole, from this new wire, what i think looks like an antenna has been installed. It is driving me NUTS, not knowing what it is for. Some one please fill me in. This is in Redwood in Christchurch, the photo is poor i know, i might take a more detailed one later...