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Figure 1: In-building BPL can be used to interconnect PCs or other devices within a building, using that building's electrical wiring. Access BPL extends that connection to the Internet, using electrical distribution wiring. This slide provided courtesy of Cosy MUTO, JH5ESM. |
There are three major categories of PLC:
Access BPL uses electrical distribution lines, overhead or underground, to provide broadband Internet access to homes and businesses. Because their wiring is physically large, often overhead and extends across entire communities, access BPL systems pose a significant interference potential to over-the-air radio services. Amateur Radio is not the only potentially affected service from these types of systems. There are a number of different techniques used in access BPL, from spread spectrum to OFDM (multi-carrier signals). Studies done by amateurs in Europe, Japan and the US leave little doubt that access BPL that uses overhead electrical distribution wiring poses an interference risk to HF.
In-building BPL systems are designed to use the electrical wiring within a building to network computers. Most operate under the HomePlug specification. (See the HomePlug-related link following). HomePlug systems used within a building have notches in their product specifications, to protect over-the-air Amateur Radio operation.
Control PLC operates below 500 kHz, and is used by electric-utility companies to control their equipment using the power-lines as transmission lines. This type of PLC does not pose any significant interference risk to HF operation.
