Distance effects in low-frequency power line communications

Most power line communications systems operate at frequencies no less than 9 KHz. Lower frequency systems, while slower in symbol rate, have the advantage of propagating over long distances. There is therefore no need for repeaters and signal boosters which can make deployment in sparsely populated areas prohibitively expensive. We introduce a novel circuit for generating narrowband, low-frequency pulses. We present data acquired using this circuit at several rural utilities wherein the signal is measured at the point of generation and at the substation supplying that point, and the signal attenuation is inferred. Statistical analysis of these results demonstrates that there is no discernable, consistent degradation in signal strength with distance up to at least 12 km.