Icom AT-130, Инструкция по эксплуатации

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ANTENNA SYSTEM
n
Coaxial cable
Insulate the lead-in cable of the AT-130/E antenna ter-
minal and antenna element from other metal objects.
To prevent interference, keep cables as far as pos-
sible from an antenna, electric pump and other elec-
tronic equipment.
To prevent erroneous indications, keep cables as far
away as possible from the flux gate compass.
Use suitable noise filters for alternators, fluorescent
lights, etc. Ask your Dealer for details.
n
Ground and counterpoise
Why a ship’s ground is required
The AT-130/E’s ground terminal
MUST be connected
to your ship’s ground. Grounding prevents electric
shocks, interference to other equipment and other
problems. Grounding also ensures effective signal
transmission.
R DANGER! NEVER
connect the ground terminal
to the following points. These connections may cause
an explosion or electric shocks:
• Gas or electrical pipe
• Fuel tank
• Oil-catch pan
IMPORTANT:
The mounting plate is NOT connected
to the AT-130/E’s internal ground. Non-through mast
is
NOT electrically connected to sea water.
Ideal ground points
One of following points is ideal:
• Ship’s ground terminal
• External ground plate
• External copper screen
Good ground points
If electrically connected to sea water, one of the fol-
lowing points is usable:
• Stainless steel tuna tower
• Stainless steel stanchion
• Through mast
• Through hull
• Metal water tank
Undesirable ground points
These connections may cause noise or electrolysis:
• Engine block
• Keel bolt
Electrolysis
All ground cables from the AT-130/E, HF transceiver,
etc. on your ship should be connected to only one
ship’s ground.
DO NOT
connect to two or more points. Voltage
difference between two or more ship’s grounds may
cause electrolysis.
DO NOT
connect between dissimilar metals where
an electric current is present. These connections may
cause electrolysis.
Counterpoise
If your ship is made of FRP, etc. and a good ship’s
ground is not available, connect a counterpoise.
Ground terminal
AT-130/E
1
⁄
4
λ
radial for
each band
1 ⁄
4
λ
(quarter wavelength) radial for each band is suit-
able for a counterpoise. Install the counterpoise di-
rectly below the AT-130/E’s ground terminal. Insulate
the ends of each radial from other metal objects. Lay-
out the radial horizontally and as straight as possi-
ble.
L : Counterpoise length for the operating frequency [m]
f : Operating frequency [MHz]
L =
300
f
×
1
4
[Example]
At an operating frequency of 16 MHz, use a counter-
poise with the following length:
L =
300
16
×
1
4
4.7 [m]
1 m 39 inches
Ground cable
For best results, use the heaviest gauge wire or metal
strap available. Make the distance between the AT-
130/E’s ground terminal and ship’s ground as short
as possible.
The supplied ground cable can be used for ground
connection through a mast. Confirm that the through
mast is electrically connected to sea water.
R WARNING!
— When grounding to metal hull
Use a Zinc anode to protect the hull from electroly-
sis. Ask your technical dealer or installer, or refer to
a technical book for RF ground details.