Antenna Coupler; Fs-2575 And Fs-5075 - Furuno FS-1575 Service Manual

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7.9 Antenna Coupler

7.9.1 FS-2575 and FS-5075: AT-5075(05P0875) / FS-1575:

AT-1575(05P0883)

The FS-2575 and FS-5075 systems use AT-5075 antenna coupler, and the FS-1575 system

uses AT-1575 antenna coupler. These antenna couplers have a built-in COUP board and

are the same in the circuit and operation.

The tunable frequency range is between 1605 kHz and 27500 kHz and required antenna

length is 10 meters. For example, in case of an 8m whip antenna, install it using a lead-in

of 2 m or more in length.

Tuning time is 15 seconds at maximum. Basically, the matching circuit is switched to the

gamma-matching circuit on the MF band and to the pi-matching circuit on the HF band.

Depending on antenna constants, it is switched to the pi-matching circuit even on the MF

band. The matching circuit works to switch between L (inductance) and C (capacitance)

using a relay, minimizing VSWR. When VSWR falls below "3," tuning is determined to

CONFIDENTIAL (internal use only)

This confidential document is used only by FURUNO authorized persons.

It is strictly prohibited to reproduce the document in whole or in part without prior written permission of FURUNO.

C1-24, 141-144

Fig. 7.9.1 COUP Board (05P0875) Block Diagram

P50-57, P81-83

7.9 Antenna Coupler

COUP (05P0875)

Fs-2575 Fs-5075