In the first days of broadcast radio in the first half of the
twentieth century, Radio Frequency Interference (RFI) was dealt
with by government authorities by reducing the power of one transmitter
so it didn’t interfere with another licensed broadcast territory.
The term “RFI” continued to be used to describe interference
problems between equipment until around the 1960s when the term
“EMC” began to be popular.
Electromagnetic Compatibility (EMC) defined the successful operation
of equipment in its environment including radiated disturbances,
conducted disturbances, electrostatic discharges, and similar
phenomena. The EMC Society was initially the Professional Group
on Radio Frequency Interference and changed its name to the Professional
Group on EMC in 1963. So, over the years since 1963, the term
RFI became less popular and fell out of favor.
But, now, RFI is coming back because of the proliferation of wireless
devices and wireless technologies, both licensed and unlicensed.
In today’s context, RFI is frequently used to refer to the
interference from the radios in complex cellular phones, laptop
computers, and similar devices. Engineers are now concerned with
the interference potential of electronic circuitry within a device
to the radios within the device and vice-versa. So, RFI started
as a term defining interference between separate devices but is
now increasingly being used to describe intra-system interference
from small but powerful radio technologies.
So, we welcome back the resurgence of the term “RFI”
in a new context.
Dan Hoolihan
January 2007
