T/R Unit Output Power Adjustment And Measurement; Preparation; Connection; Preparation For Measurement - Furuno FS-1575 Service Manual

5.2 T/R Unit Output Power Adjustment and Measurement

5.2.1 Preparation

1. Connection

As shown below, connect a 50 ohm power meter to the [T/R ANT] terminal of the
FS-xx75T system.
Select a dummy load with appropriate power capacity according to TX power. In this
case, select a non-inductive resistor. The dummy load should have power capacity twice
as much as TX output power to be measured.
FS-2575C
Fig. 5.2.1 Output Power Measurement Circuit of Transceiver Unit

2. Preparation for measurement

Since no Antenna coupler; ATU is connected, TUNE ERROR occurs when transmitting.
To prevent this error,
• select [MENU] -> 9.SERVICE -> 3.RT SETUP -> 1.SETUP -> TX TUNE ->
"OFF," or
• connect a jumper between "#7: TUNE OK" and "#9: TUNE" of TB6 on the T-IF
board.
Be sure to restore the setup upon completion of adjustment.
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.
5.2 T/R Unit Output Power Adjustment and Measurement
50 ohm
power meter
FS-5075T T/R ANT
FS-2575T
50 ohm
FS-1575T
coaxial cable
5-14
ex: 50 ohm/1kW
Dummy load
50 ohm
coaxial cable
TB6 #7-#9 Jumper