El ectromagn etic I nterfe re n ce (EMI)
from Radio Wave Sources
The INDEPENDENCE" iGLIDE'* Manual Assist
Wheelchair may be susceptible to electromagnetic
interference (EMl), which is interfering electromagnetic
(EM) energy emitted from sources such as radio
stations, W stations, amateur radio (HAM) transmitters,
two-way radios, and cellular phones. The interference
(from radio wave sources) can cause a manual assist
wheelchair to move by itself or to move in unintended
direclions. It can also permanently damage a manual
assist wheelchair's control system.
The intensity of the EMI can be measured in volts per
meter (V/m). A manual assist wheelchair can resist EMI
up to a certain intensity called the "immunity level";
the higher the immunity level, the greater the
protection. At this time, current technology is capable
of achieving at least a 20Y/m immunity level, which
provides useful protection from the more common
sources of radiated EMl. The immunity level of this
model of the INDEPENDENCE" iGLIDE'" Manual
Assist Wheelchair, as shipped with no further
modification, is 20 V/m.
There are a number of sources of relatively intense
electromagnetic fields in the everyday environment.
Some of these sources are obvious and easy to avoid.
Others are not apparent, and exposure is unavoidable.
However, we believe that by following the warnings
listed below, your risk from EMI will be minimized.
The sources of radiated EMI can broadly be classified
into these three types:
1) Handheld portable transceivers (transmitters-
receivers) with the antenna mounted directly on
the transmitting unit. Examples include: citizens
band (CB) radios; walkie-talkies; security, fire, and
police transceivers; cellular telephones; and
other personal communication devices. NOTE:
Some cellular telephones and similar devices
transmit signals while they are ON. even when not
being used.
2) Medium-range mobile transceivers, such as those
used in police cars, fire trucks, ambulances, and
taxis.'These usually have the antenna mounted on
the outside of the vehicle.
3) Long-range transmitters and transceivers, such
as commercial broadcast transmitters (radio
and W broadcast antenna towers) and amateur
(HAM)radios.
NOTE: Other types of handheld devices such as
cordless phones, laptop computers, AM/FM radios,
TV sets, CD players, and cassette players, and small
appliances, such as electric shavers and hair dryers, so
far as we know, are not likely to cause EMI problems
to your iGLIDE'M Manual Assist Wheelchair.
Manual Assist Wheelchair Electromagnetic
lnterference (EMI)
Because EM energy rapidly becomes more lntense
as one moves closer to the transmitting antenna
(source), the EM fields from handheld radio wave
sources (transceivers) are of special concern. lt is
possible to unintentionally brlng high levels of EM
energy very close to the powered wheelchair! control
system while using these devices. This can affect
manual assist wheelchair movement. There{ore, the
warnings listed below are recommended to prevent
possible interference with the control system of the
manual assist wheelchair.
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