MFJ-9232 Mini Loop Tuner
TM
Instruction & Technical Manual
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Step 5
Tune the transceiver or receiver to the band and frequency of interest and “Ear-ball” tune the MFJ-
9232 Mini Loop Tuner controls for maximum noise and S-Meter reading. “Ear-balling”, like “Ball-
parking” is a term often used to describe the listening process as used to hear a “peak” in reception
before actually applying a transmit signal to the tuner. The tuner will produce a peak when the proper
positions for the controls are achieved. The normal process consists of the following suggested
instructions:
•
Slowly rotate TUNING control clockwise while listening for a peak until you reach position
“High Freq.”
•
If no peak is found, re-position TUNING control to “Low Freq.”
•
Rotate MATCHING control counter-clockwise approximately 1/16 of a full turn.
•
Slowly rotate TUNING control clockwise while listening for a peak until you reach position
“High Freq.”
•
If no peak is found, re-position TUNING control to “ Low Freq.”
•
Rotate MATCHING control counter-clockwise approximately 1/16 of a full turn.
•
Slowly rotate TUNING control clockwise while listening for a peak until you reach position
“High Freq.”
•
Repeat this sequence until the MATCHING control reaches position “Max C”.
•
If no peak is found, the loop length is incorrect for the frequency of interest.
•
Once a peak is found, alternately adjust TUNING and MATCHING controls until the peak is
maximized.
Step 6
Apply no more than 5-10 Watts of power to the MFJ-9232 Mini Loop Tuner and adjust the TUNING
and MATCHING controls for minimum SWR on your external WR/Wattmeter. Readjust the controls
until you see no further improvement in minimum SWR. Then, apply more power if required to
maintain communication (do not exceed 25 Watts).
Step 7
Be sure that MPE distance standard as defined in Supplement B of the FCC OET Bulletin 65, version
97-01 is met. Should any arcing be detected, stop transmitting and check connections and proximity
to objects that may be suspect. If arcing seems to be inside of the MFJ-9232 tuner, lower output
power and re-check for arcing.
Step 8
You can now enjoy operating in your favorite mode. However, if you change frequency more than
about 5 KHz, you may find you’ll need to re-adjust the TUNING controls for minimum SWR. Rotate
TUNING clockwise for higher frequencies and counter clockwise for lower frequencies. Even greater
frequency excursions can cause the MATCHING control to also require adjustment.
This concludes the MFJ-9232 Mini Loop Tuner System Operation instructions.