MFJ MFJ-941E, User Manual

MFJ-941E Versa Tuner II

1

MFJ VERSA TUNER II

GENERAL INFORMATION:

The 

MFJ-941E

 is designed to match virtually any transmitter to any antenna, including dipoles, inverted-vees, verticals,

mobile whips, beams, random wires, and others fed by coax lines, balanced lines or a single wire.  An eight-position
antenna-selector switch provides versatile antenna selection.  The 

MFJ-941E

 will handle up to 300 Watts of transmitter

RF output power.  The 

MFJ-941E

 employs a cross-needle meter so forward power, reflected power and SWR may be

read simultaneously.

CROSS-NEEDLE SWR/WATTMETER:

The meter on the 

MFJ-941E

 may be used alone or with the tuner.  Set the 

ANTENNA SELECTOR

 to 

COAX 1 DIRECT

or 

COAX 2 DIRECT

 to use the meter without the tuner.  The 

MFJ-941E

 utilizes a cross-needle meter so FORWARD

power, REFLECTED power and SWR may be read 

simultaneously

 in two ranges.  FORWARD power may be read by

setting the power range switch to 

HI

 (

300

 Watts) or 

LO

 (

30

 Watts).  Next read the power level on the 

FORWARD

SCALE

.  REFLECTED power is shown simultaneously on the 

REFLECTED SCALE

.  SWR is determined by observing

the intersection point of the two needles.  No SWR sensitivity adjustment is needed to read SWR.  The 

HI

 range is 

300

Watts FORWARD and 

60

 Watts REFLECTED.  The 

LO

 range is 

30

 Watts FORWARD and 

6

 Watts REFLECTED.  The

difference between the 

HI

 and 

LO

 scales readings is a factor of 

10

.

The meter lamp can be powered by a 12 Vdc source, such as the optional 

MFJ-1312B

 power supply.  Use a 2.1mm

coaxial plug with the center conductor of the plug connected to the positive and the sleeve connected to ground.  The

METER LAMP ON/OFF

 switch will activate the meter lamp.

ANTENNA SELECTOR:

The 

ANTENNA SELECTOR

 switch utilizes eight positions.  They are 

DUMMY LOAD

, 

BALANCE LINE

, 

COAX 1

, and

COAX 2

 positions for both 

BYPASS

 (direct) and 

TUNED

 (through) the tuner operation.  An external 50 Ohm dummy

load can be connected to the 

EXT LOAD

 connector located at the rear of the tuner.  Do not continuously key into the

dummy load for more than 2 minutes at a time.

CAUTION:

Never use the 

MFJ-941E

 for 

OVER

300 Watts

 of RF output power, even in the

DIRECT

 or 

DUMMY LOAD

 positions.