Antenna System; I Antenna For Ship - Icom AT-141 Instruction Manual

1

ANTENNA SYSTEM

I Antenna for ship

Required antenna element length
Required antenna element length to achieve full per-
formance varies according to the lowest frequency:
The lowest frequency Required antenna element length
1.6 MHz band
4 MHz band
The longer the antenna element, the better the an-
tenna efficiency.
Undesirable antenna element lengths
AVOID
multiples of
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, ...)
300
1
× ×
L = n
2
f
[Example]
At an operating frequency of 16 MHz, avoid the fol-
lowing antenna element lengths:
300
1
× ×
n
L =
16 2
39 inches
1 m
For example, if 15 m is selected for an antenna ele-
ment length, you have no problem in the 1.6–25 MHz
marine bands range.
1
7 m; 23.0 feet or longer
3 m; 9.8 feet or longer
λ (half wavelength) for an-
1
⁄
2
9.4, 18.8, ...
Insulator
Backstay operates as
a long-wire antenna.
Insulator
NOTE: Keep antennas as far away from other objects
as possible, especially metal objects.
Whip antenna