Grounding - Yaesu FT-950 Operating Manual

Hf/50 mhz transceiver
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I
NSTALLATION AND
The FT-950 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 cur-
rent flow through logic devices.
An effective earth ground system may take several forms; for a more complete discussion, see an appropriate RF engineer-
ing 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 base 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 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 transceivers, power supplies, and data communica-
tions devices (TNCs, etc.) should be made directly to the ground bus using a heavy, braided cable.
Do not "Daisy-Chain" ground connections from one electrical device to another, and thence to the ground bus. This method
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 to ensure continued 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.
Transceiver
Linear
Amplifier
P
G
ROPER
ROUND
FT-950 O
PERATING
G
TNC
C
ONNECTION
M
ANUAL
I
NTERCONNECTIONS
ROUNDING
Transceiver
I
MPROPER
Linear
TNC
Amplifier
"Daisy Chain"
G
C
ROUND
ONNECTION
Page 9

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