III. What Is Required Under FCC Rules (By Ed Hare, ARRL Laboratory Manager)

Radio and television noise is governed by FCC Part-15 regulations. These rules specify three classes of emitters that may apply to power-company equipment:

• Incidental emitters: Most interference complaints from power-company equipment results from an incidental emitter. Incidental emitters don't intentionally generate radio energy, but incidentally does so as a result of its operation. Examples of incidental emitters include electric motors and sparking power-line hardware.

• Unintentional emitters: These may be found in some power-company equipment. Unintentional emitters intentionally generate an internal radio signal, but do not intentionally radiate or transmit it. Examples include some types of "switch-mode" power supplies and microprocessors used in some power-company equipment. Unintentional emitters have specific limits on radiated and conducted emissions.

• Intentional emitters: These are transmitters that intentionally radiate RF. In general, they are not found in power company equipment, although some remote-reading usage meters may use intentional emitters.

Most radio noise on power-company equipment comes from incidental emitters. These have no specific limits on conducted or radiated emissions. But all unlicensed emitters of radio energy have a requirement not to cause harmful interference. If they do, the operator of the device causing the interference must take whatever steps are necessary to correct it.

It is always best for a utility to be responsible for correcting its own problems. By responding to interference complaints appropriately, a utility need only address those areas where existing power-line noise is actually causing a problem. This is a far better solution than waiting for the FCC to mandate and define specific requirements, perhaps asking for improvements to be made system wide, rather than on a case-by-case basis.