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SYSTEM INSTALLATION
* The AT-140 is housed in a durable, completely weather
resistant case. You don’t have to worry a lot about rain,
splash, and so on.
Five Critical Points for a successful HF installation
■
These critical points apply to almost any HF installa-
tion, whether it is for a base station, in a vehicle, or
a marine vessel. For the best and most reliable com-
munication capability, use them during the planning
and installation of your HF system.
1. Install transceiver as close as possible to your ves-
sel’s operation location and to your power source,
whether you are using batteries or an external
power supply.
2. Install the antenna in an open location as far as
possible from your operating station.
3. Install the antenna tuner in an
open location*
as
close to the base of your antenna as possible.
4. Install copper straps or radial wires as your ground
system. These will give you a good solid ground
system, which is critical for reliable communica-
tions.
5. Make all your power source, control and coaxial
cables as short as possible. Do not coil up any
cables that are longer than they should or could
be.
Following these rules will minimize marginal installa-
tions and problem sources such as RF feedback in
the transceiver, power supply or cables and “hot” or
RF burning microphones.
If all 5 above points are followed during the design
and installation of your HF system, the operator can
expect top performance.
Vessel ground connection
■
The HF system MUST have an adequate RF ground
connection. Otherwise, the overall efficiency of the
HF system installation will be reduced. Electrolysis,
electrical shocks and interference from other equip-
ment could also occur.
For best results, use 50 or 75 mm (2 or 3 inches)
wide copper strap and make the connection as short
as possible. Ground the HF system to one ground
point, otherwise the voltage difference (in RF level)
between 2 ground points may cause electrolysis.
R
WARNING—
When grounding to a metal hull
Use Zinc anodes to protect the hull from electroly-
sis.
Ask your technical dealer, installer or refer to a
technical book for RF grounding details.
CAUTION: NEVER
connect the HF system to a
“positive-grounded ship,” otherwise it will not func-
tion.
Ground system example
Best ground points
• External ground plate
• Copper screen
• Copper foil
Acceptable ground point
• Stainless steel stanchion
• Through mast
• Through hull
• Metal water tank
Undesirable ground points
• Engine block
• Ship’s DC battery ground
Unusable ground points
( these connections may cause an explosion or electrical
shock)
• Gas or electrical pipe
• Fuel tank or oil-catch pan
Copper pipe
Metal object
Copper screen
Transceiver
Antenna tuner
