Power line communications

An electricity distribution network for sensing a plurality of subscribers, the network incorporating an apparatus according to any one of the preceding claims, and wherein the wanted signal comprises a telecommunication, signal which is coupled onto a distribution wire of the network.

A method of coupling communications signals on to an electricity distribution network comprising a substation serving a plurality of distribution lines, the method comprising:

• coupling communications signals occupying a frequency band to one of the lines by coupling a wanted communications signal onto the line at a first position and coupling a cancelling signal onto a line at a second position, spaced from the first position such that the wanted communications signal and cancelling signal destructively combine in a direction of propagation towards the substation;
• and,
• reusing the frequency band for coupling different communications signals on to another one of the plurality of lines.

Apparatus for coupling telecommunications signals to a power line, the apparatus comprising:

• a first means for coupling a wanted telecommunications signal onto the power line at a first position;
• a second means for coupling a cancelling signal onto the power line at a second position, spaced from the first position;
• wherein the wanted telecommunications signal and the cancelling signal are arranged to destructively combine in a single direction of propagation along the power line while enabling the wanted signal to propagate in the other direction along the power line.

A method of coupling telecommunications signals to a power line, the method comprising:

• coupling a wanted telecommunications signal onto the power line at a first position;
• coupling a cancelling signal onto the power line at a second position, spaced from the first position;
• and wherein the wanted telecommunications signal and the cancelling signal are arranged to destructively combine in a single direction of propagation along the power line while enabling propagation of the wanted signal along the power line in the other direction.