Antenna System; Antenna For Ship; Antenna For Land Operation - Icom AT-140 Instruction Manual

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ANTENNA SYSTEM

Antenna for ship

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D Required antenna element length
Required antenna element length to achieve full per-
formance varies, according to the lowest frequency.
The lowest frequency
1.6 MHz band
4 MHz band
The longer the antenna element, the longer commu-
nication distance.
D Undesirable antenna element lengths
DO NOT
use an antenna element such as mul-
λ lengths (half wavelength), since tuning
tiples of 1 ⁄
2
becomes difficult.
L : Undesirable antenna element length [m]
f : Operating frequency [MHz]
n : Natural number (n = 1, 2, 3, ...)
300 1
L = × × n
2
f
[Example]
At an operating frequency of 16 MHz, avoid the fol-
lowing antenna element lengths:
300 1
×
×
L = n
16 2
39 inches
1 m
For example, if 15 m (49.2 feet) is selected for an
antenna element length, you have no problem in the
1.6 to 25 MHz marine bands range.

Antenna for land operation

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In some countries, HF transceivers can be used for
land mobile operation. Ask your Icom Dealer for de-
tails, since the radio law varies according to each
country.
For land mobile operation on 4 MHz or above, an
optional AH-2b
antenna element
AH-2b includes a sturdy tow hook mount system for
holding a 2.5 m (8.2 feet) stainless steel antenna ele-
ment plus all the necessary hardware.
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Required antenna element length
7 m (23.0 feet) or longer
3 m (9.8 feet) or longer
9.4, 18.8, ...
is available. The
AH-2b
Insulator
Backstay operates as
a long-wire antenna.
Insulator
NOTE: Keep antennas as far away from other ob-
jects as possible, especially metal objects.
Refer to the AH-2b instruction manual for the AH-2b
and AT-140 installation to your vehicle. Ask your
Icom Dealer for details.
Connect a suitable antenna element for a base sta-
tion. To achieve full performance, refer to "Required
antenna element length" as described above.
Whip antenna