Icom AT-141 User Manual
INSTRUCTION MANUAL
HF AUTOMATIC
ANTENNA TUNER
AT-141
FOREWORD
Ground terminal
Mounting plate
q
w
e
r
t
y
u
i
o
!0 !1
!2
PRECAUTIONS
Thank you for purchasing the AT-141 HF AUTO-
MATIC ANTENNA TUNER
The AT-141 is designed, primarily for use with Icom HF
transceivers.
Refer to your HF transceiver instruction manual for operation. If you have any questions, contact your dealer.
.
IMPORTANT
READ ALL INSTRUCTIONS carefully and com-
pletely before using the AT-141.
SAVE THIS INSTRUCTION MANUAL. This in-
struction manual contains important safety and installation instructions.
EXPLICIT DEFINITIONS
Word Definition
R WARNING
CAUTION Equipment damage may occur.
NOTE
Personal injury, fire hazard or electric
shock may occur.
If disregarded, inconvenience only. No
personal injury, fire hazard or electric
shock.
R DANGER HIGH VOLTAGE! NEVER touch
the antenna terminal, ground terminal, antenna or
counterpoise while transmitting. Place the AT-141, antenna and counterpoise in positions where no one can
touch them.
NEVER use without a ground connection.
NEVER transmit during internal adjustment. This may
cause an electric shock.
USE the ground terminal for ground connection.
The mounting plate is not connected internally.
DO NOT operate your HF marine transceiver without
running the boat’s engine.
AVOID using the AT-141 in areas where the temper-
ature is below –30°C or above +60°C.
SUPPLIED ACCESSORIES
The following accessories are supplied with the AT-141. Qty.
Icom, Icom Inc. and the logo are registered trademarks of Icom Incorporated (Japan) in the United States, the United Kingdom, Germany, France, Spain, Russia and/or other countries.
i
q U-bolts ……………………………………………… 2
w U-bolt plates ……………………………………… 2
e Flat washers (M6 large) ………………………… 8
r Flat washers (M6 small) ………………………… 4
t Spring washers (M6) ……………………………… 8
y Nuts (M6) …………………………………………… 8
u Hex head bolts (M6×50) ………………………… 4
i Self-tapping screws (A0 6×30) …………………… 4
o Weatherproof cap ………………………………… 1
!0 4-pin connector …………………………………… 1
!1 Connector pins …………………………………… 4
!2 Ground cable (OPC-412) ………………………… 1
MISCELLANEOUS ITEMS
TABLE OF CONTENTS
The following parts are additionally required for installation, but are not supplied with the AT-141.
Purchase these parts locally.
q AWG 14×4-conductor shielded cable
*Icom offers an optional OPC-1465
Length: 10 m; 32.8 feet
w 50 Ω coaxial cable
e PL-259 connectors
CONTROL CABLE
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FEATURES
Matches all bands
The AT-141 matches any frequency on every HF marine band. For example, the tuner matches a 7 m; 23 ft
long-wire antenna across 1.6–30 MHz.
Full automatic tuning
Just push the [TUNE] key on the transceiver, and the
AT-141 adjusts immediately to the minimum SWR of
any frequency on any HF marine band.
HF operation on any size ship
The AT-141 allows you HF operation where antenna
element length is restricted due to space.
Weather resistant
The AT-141 is housed in a durable, completely weather
resistant ASA case with a rubber gasket. The antenna
tuner can be conveniently installed both on the deck or
in the cabin near the antenna element.
FOREWORD …………………………………………… i
IMPORTANT …………………………………………… i
EXPLICIT DEFINITIONS ……………………………… i
PRECAUTIONS ……………………………………… i
SUPPLIED ACCESSORIES ………………………… i
MISCELLANEOUS ITEMS ………………………… ii
FEATURES …………………………………………… ii
TABLE OF CONTENTS ……………………………… ii
1 ANTENNA SYSTEM …………………………… 1–2
■ Antenna for ship ………………………………… 1
■ Coaxial cable …………………………………… 2
■ Ground and counterpoise ……………………… 2
2 INSTALLATIONS ………………………………… 3–5
■ Installation outline ……………………………… 3
■ Control cable……………………………………… 3
■ PL-259 connector………………………………… 4
■ Mounting ………………………………………… 4
■ Cable connections ……………………………… 5
3 CONTROL CABLE SIGNALS …………………… 6
■ Terminal information …………………………… 6
4 UNIT DESCRIPTION AND SPECIFICATIONS … 7
■ Unit description…………………………………… 7
■ Specifications …………………………………… 7
Simple installation
Installation is simple. Just connect the control and antenna cables. You never need to open the cover.
45 memories for shorter tuning time
To decrease the tune-up time, the AT-141 automatically
stores the matching conditions for up to 45 frequencies.
Re-tuning for a memorized frequency takes approx. 1
sec.
Super capacitor for memory backup
Even if the AT-141 is not used for approx. 1 week, the
built-in super capacitor backs up contents of the 45
memories.
Low power tune up
The AT-141 emits low output power during tuning. This
feature reduces the possibility of causing interference
to other stations.
Tuner through function
The tuner through function is built into the AT-141. This
function helps improve receiver gain, depending on the
antenna element length used, and operating frequency.
ii
1
Insulator
Backstay operates as
a long-wire antenna.
Insulator
Whip antenna
L =
300
16
×
1
2
n
×
9.4, 18.8, ...
1 m
39 inches
L =
300
f
×
1
2
n
×
ANTENNA SYSTEM
■ Antenna for ship
Required antenna element length
Required antenna element length to achieve full performance varies according to the lowest frequency:
The lowest frequency Required antenna element length
1.6 MHz band 7 m; 23.0 feet or longer
4 MHz band 3 m; 9.8 feet or longer
The longer the antenna element, the better the antenna efficiency.
Undesirable antenna element lengths
AVOID
tenna element lengths, since tuning becomes difficult.
L : Antenna element length to be avoided [m]
f : Operating frequency [MHz]
n : Natural number (n = 1, 2, 3, ...)
multiples of 1⁄2λ (half wavelength) for an-
[Example]
At an operating frequency of 16 MHz, avoid the following antenna element lengths:
For example, if 15 m is selected for an antenna element length, you have no problem in the 1.6–25 MHz
marine bands range.
NOTE: Keep antennas as far away from other objects
as possible, especially metal objects.
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