Grounding - Yaesu FT-450 Operation Manual

I
NSTALLATION
The FT-450 transceiver, like any other HF communications apparatus, requires an effective ground system for
maximum electrical safety and best communications effectiveness. A good ground system can contribute to
station efficiency in a number of ways:
It can minimize the possibility of electrical shock to the operator.
It can minimize RF currents flowing on the shield of the coaxial cable and the chassis of the transceiver.
Such currents may lead to radiation, which can cause interference to home entertainment devices or
laboratory test equipment.
It can minimize the possibility of erratic transceiver/accessory operation caused by RF feedback and/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 below is intended only as a guideline.
Typically, the ground connection consists of one or more copper-clad steel rods, driven into the ground. If
multiple ground rods are used, they should be positioned in a "V" configuration, and bonded together at the apex
of the "V" which is nearest the station location. Use a heavy, braided cable (such as the discarded shield from
type RG-213 coaxial cable) and strong cable clamps to secure the braided cable(s) to the ground rods. Be sure
to weatherproof the connections to ensure many years of reliable service. Use the same type of heavy, braided
cable for the connections to the station ground bus (described below).
Inside of the station, a common ground bus consisting of a copper pipe of at least 25 mm (1") diameter should
be used. An alternative station ground bus may consist of a wide copper plate (single-sided circuit board material
is ideal) secured to the bottom of the operating desk. Grounding connections from individual devices such as
transceivers, power supplies, and data communications devices (TNCs, etc.) should be made directly to the
ground bus using a heavy, braided cable.
Do not make ground connections from one electrical device to another, and thence to the ground bus. This so-
called "Daisy-Chain" grounding technique may nullify any attempt at effective radio frequency grounding. See
the drawing below for examples of proper grounding techniques.
Inspect the ground system - inside the station as well as outside - on a regular basis so as to ensure maximum
performance and safety.
Besides following the above guidelines carefully, note that household or industrial gas lines must never be used
in an attempt to establish an electrical ground. Cold water pipes may, in some instances, help in the grounding
effort, but gas lines represent a significant explosion hazard, and must never be used.
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G
ROUNDING
Transceiver Linear
Amplifier
P G
ROPER ROUND
Transceiver Linear
Amplifier
"Daisy Chain"
I G
MPROPER ROUND
TNC
C
ONNECTION
TNC
C
ONNECTION
FT-450 O M