Grounding - Yaesu FT-100D Operating Manual

Installation
GROUNDING
The provision of an effective ground system is important in any successful communica-
tions station. A good ground system can contribute to station efficiency in a number of
ways:
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It can minimize the possibility of electrical shock to the operator.
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It can minimize RF currents flowing on the shield of the coaxial cable and the
chassis of the transceiver which may cause interference to nearby home entertain-
ment devices or laboratory test equipment.
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It can minimize the possibility of erratic transceiver operation caused by RF feed-
back or improper current flow through logic devices.
An effective earth ground system may take several forms; for a more complete discussion,
see an appropriate RF engineering text. The information presented below is intended only
as a guideline.
Inspect the ground system - inside the station as well as outside - on a regular basis so as
to ensure maximum performance and safety.
Mobile Station Grounding
Although satisfactory grounding in most installations will be achieved via the DC cable's
negative lead and the antenna system's coaxial cable shield, it is often recommended that
you provide a direct ground connection to the vehicle chassis at the mounting location of
the transceiver (installation using the MMB-48 Mobile Bracket will accomplish this, if the
MMB-48 itself is mounted to the vehicle's chassis). Due to unexpected resonances which
may naturally occur in any location, improper communication system performance may
result from insufficient grounding. These symptoms may include:
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RF feedback (resulting in distortion on your transmitted signal);
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Unintended frequency change;
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Blinking or blanking of the frequency display;
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Noise pickUp; and/or
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Loss of memory.
Note that these conditions may occur in any communications installation. The FT-JOO
includes extensive filtering designed to minimize the chance of such problems; however,
random currents set up by insufficient RF grounding can nullity such filtering. Bonding the
rear panel Ground lug of the FT-J 00 transceiver to the vehicle or vessel's ground system
should clear up any such difficulties.
Yaesu does not recommend the use of "on glass" mobile antennas unless the shield of the
coaxial cable is securely grounded near the feedpoint of the antenna. Such antennas fre-
quently are responsible for the ground-related difficulties described above.
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FT-100
MICRO MOBILE OPERATING MANUAL