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B R I E F I N G T H E W E A R E R
Anyone wearing abody transmitter for the first time may
experience the same self-consciousness experienced when
wearing aconcealed weapon. The unconventional nature of
the body transmitter causes the wearer to feel that everyone
he meets will immediately notice the bulge and identify the
reason. This feeling will lessen with experience.
The wearer must be cautioned about interrupting the
suspect. He must be convinced that his role as aquiet listener
is essential to successful recording. He must avoid leaning
against steel or walls containing structural steel objects, filing
cabinets, desks, and etc., which can absorb or alter the signal
pattern of the transmitter. He must be trained to restrict body
movements and to avoid making interfering sounds.
B O D Y A N T E N N A S I G N A L P R O PA G AT I O N
When an RF transmitter is worn on the body, the antenna is
also worn on the body. The human body can have agreat
effect on the transmitter signal pattern, resulting in reduced
effective signal propagation and range.
For example, when the wearer is standing in an upright
position, the signal pattern is not uniform in all directions (not
omni-directional). Most signal propagation is forward from the
antenna with abroad peak (maximum signal) centered toward
the front and to the left when the antenna is vertically oriented
on the chest area, left of center. The signal gradually
decreases in strength moving toward the wearer's back with a
null (weakest signal) occurring behind the wearer's right
s h o u l d e r.
T h e m a x i m u m f o r w a r d s i g n a l i s d u e t o m i n i m u m
obstructions in front of the antenna. The null in the backward
direction is aresult of the body blocking or absorbing much of
the signal.
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