The Issue of Power-Line Noise
A Smarter Approach
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.
Page last modified: 03:30 PM, 05 Jan 2005 ET
Page author: tis@arrl.org
Copyright © 2005, American Radio Relay League, Inc. All Rights Reserved.