1 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 multiples of 1⁄2λ (half wavelength) for antenna 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, ...)

L = 300 ⋅

1 ⋅ n

f

2

[Example]

At an operating frequency of 16 MHz, avoid the following antenna element lengths:

L =

300

⋅

1

⋅ n

9.4, 18.8, ...

 

16

 

2

 

 

1 m

39 inches

 

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.

Insulator

Backstay operates as a long-wire antenna.

Insulator

Whip antenna

NOTE: Keep antennas as far away from other objects as possible, especially metal objects.

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