MFJ MFJ-9201 User manual

INSTRUCTION MANUAL
CAUTION: Read All Instructions Before Operating Equipment
MFJ ENTERPRISES, INC.
300 Industrial Park Road
Starkville, MS 39759 USA
Tel: [phone] Fax: [phone]
COPYRIGHT 2011 MFJ ENTERPRISES, INC.
C
Model MFJ-9201
VERSION 1A

MFJ-9201 QRPocket Antenna Tuner Instruction Manual
3
INTRODUCTION
The MFJ-9201 QRPocket Antenna Tuner was specially compact-built for MFJ-
9200 series QRPocket CW Transcievers and other rigs with a built-in SWR
Meter.
You can operate 80 through 10 Meters -- anywhere with any transceiver -- use
any coax fed or random wire antenna. It’s great for mobile, base, backpack, etc.
The MFJ-9201 handles 100 watts RF output and has a tuner bypass switch. The
MFJ-9201 has BNC connectors for input and output.
INSTALLATION
The MFJ-9201 should be installed between the transmitter and antenna.
1. Locate the tuner in a convenient location at the operating position.
2. Use a 50 ohm coaxial cable to connect the transmitter or transceiver to the
BNC connector labeled XMTR on the tuner.
3.Connect an antenna feedline to the antenna BNC connector labeled ANT.
OPERATION
This tuner has a BYPASS/TUNE switch located on the unit. Simply place the
switch toward the BYPASS position to completely bypass the tuning circuit.
Change the switch toward the TUNE position to place the tuning circuit
between the transmitter/transceiver and the antenna.
In this tuner the TRANSMITTER and ANTENNA matching controls have
maximum capacitance at position 0 (fully meshed), and minimum capacitance at
position 10 (fully open). Be sure to use the highest possible capacitance for
each band. This will provide the smoothest tuning, highest efficiency, and
greatest power handling capability.
The INDUCTANCE switch has maximum inductance in positions "A" and “B”,
with minimum inductance in position "L". The use of two maximum inductance
settings improves the voltage rating and helps prevent carbon arcing. Less
inductance is needed as the frequency is increased. If too little inductance is
used, the tuner may not match the load properly. If too much inductance is used,
the tuner will be "touchy", power handling will be compromised (capacitors
could arc, etc.) and the bandwidth will not be as wide.

MFJ-9201 QRPocket Antenna Tuner Instruction Manual
4
Special Note: Always use the minimum amount of inductance as possible.
Minimum inductance gives the best efficiency, maximum power
handling, and widest bandwidth.
The MFJ-9201 covers 80 through 10 meters. Do not operate on 160 meters.
Tuning Procedure:
1. Position the TRANSMITTER control to 5 on the corresponding scale.
2. Position the ANTENNA control to 0 on the corresponding scale.
3. Place the BYPASS/TUNE switch in the TUNE position.
4. Apply just enough power to obtain noticeable deflection on your reflected
power meter or SWR meter.
5. Adjust the INDUCTOR control for lowest deflection on the reflected power.
6. Carefully adjust the TRANSMITTER control for the lowest reflected
power, then increase the ANTENNA control slightly and adjust the
TRANSMITTER control for the lowest reflected power. Again, increase
the ANTENNA control slightly and adjust the TRANSMITTER control for
lowest reflected power. Repeat this process for lowest reflected power.
Note: These controls interact. Go back and forth between these adjustments
as many times as required until the lowest reflected power (best SWR)
is obtained.
7. After the lowest reflected power (or SWR) is obtained in step 6, use the
INDUCTOR switch to reduce the inductance one switch position (L is the
lowest inductance setting). Adjust the TRANSMITTER and ANTENNA
controls for the lowest SWR. Continue this process until the lowest SWR
cannot be repeated, then use the INDUCTOR switch to increase the
inductance by one switch position (A is the highest inductance setting).
Tune for lowest SWR.
WARNING: Never transmit while changing the INDUCTOR switch.
Note: Always use as little inductance as possible. Step 7 minimizes the
inductance and maximizes the capacitance.
8. After a low SWR is obtained, the transmitter power may be increased to any
value up to 100 watts.
WARNING: Do not exceed 100 watts output. You will damage
the tuner!