Yaesu FT DX 9000MP CONTEST - DATA MANAGEMENT OPERATION, Руководство по эксплуатации

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Page 13 FT
DX
9000MP O
PERATION
M
ANUAL
IIIII
NST NST
NST NST NSTALLA
ALLA
ALLA ALLA ALLATION
TION
TION TION TION
AND AND
AND AND AND
I I I I I
NTER NTER
NTER NTER NTERCONNECTIONS
CONNECTIONS
CONNECTIONS CONNECTIONS CONNECTIONS
G
ROUNDING
The FT
DX
9000MP HF 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 effi-
ciency in a number of ways:
U
It can minimize the possibility of electrical shock to the operator.
U
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.
U
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 make 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 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 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.
Linear
Amplifier
Power
Supply
Transceiver
Transceiver Linear
Amplifier
Power
Supply
"Daisy Chain"
P
ROPER
G
ROUND
C
ONNECTION
I
MPROPER
G
ROUND
C
ONNECTION