MFJ MFJ-4113TR Instruction Manual

MFJ-4113TR Instruction Manual TX/RX SWITCH

1

MFJ-4113TR BIAS-TEE WITH TX/RX SWITCH

Introduction

The MFJ-4113TR is designed to allow connection of a receive only antenna to
your antenna system in addition to the transmitte antenna. It is also used for
MFJ-1886TR receive loop antenna and similar antennas. A key line connection
to the transiever switches the receive antenna out of the circuit when the radio
goes into transmitte mode. DC bias current is also applied to the coax
connection for the loop antenna when in receive mode. During transmit, the bias
current is removed from the receive antenna.

CONNECTIONS

12VDC

Connect your power supply for the MFJ-4113TR to this jack. The power
requrirments for this unit are 12 volts DC at 500ma. If your using this unit with
the MFJ-1886 LOOP, use the power supply that came with the loop. The loop
power supply is non-switching and produces less noise.

TRANSCEIVER

Use a coax jumper (not supplied) to connect this to your transceiver.

MFJ-4113TR Instruction Manual TX/RX SWITCH

2

XMIT ANTENNA
Connect your antenna that you want to use for transmit to this connector.

KEY

This jack should be connected to your transceivers key line. On some ICOM
radios this may be labled as SEND. On other radios, this connection may be
incorperated into the REMOTE or ACCESSORY jack. This is normally the
line that is used to key a linear amplifier. This line must be connected for proper
operation of the switch. Failure to do so will cause RF energy to be sent to the
Receive only antenna and WILL cause damage to it. The MFJ-4113TR should
click when the key line is shorted to ground by the radio. Verify its proper
operation before attempting to use the switch with your antennas.

LOOP ANTENNA (DC Pass)

This is where the receive only antenna such as the MFJ-1886 should be
connected. DC bias voltage from this connector will power the MFJ-1886 in
receive mode and will remove power when the switch is is transmit mode.

Wiring To A Receive Antenna

1. Connect the Antenna jack
on the transceiver to the
TRANSCEIVER jack on
the MFJ-4413TR.

2. Connect the Transmit
Antenna to the XMIT
ANTENNA jack.

3. Connect the MFJ-1886
line or other receive
antennas to the DC PASS
LOOP ANTENNA jack.

4. Connect the KEY jack to
the transceiver KEY line.

5. Connect 12 DC volt
power source to the +12V
jack. Center pin is
positive.