MFJ-998RT Legal Limit IntelliTuner
TM
Automatic Remote Antenna Tuner Instruction Manual
© 2011 MFJ Enterprises, Inc
MFJ-998RT Version 1A
6
Internal Controls
The internal control panel is used for testing and specialized setup and is not available for normal
operation of the MFJ-998RT. The analog meter is not included in the remote tuner. The other functions
are available only when the cover is removed for testing.
WARNING
Do not operate the tuner with high power when the cover is removed. Do not touch the components while
testing. High RF Voltages are present even with low power testing.
Control Panel
•
LCD Display: A 2-line by 16-character alphanumeric display. It displays the tuner’s various menus
and status. The display contrast can be adjusted by the LCD contrast control on the front panel.
Below the display are the SWR and power bar meter scales. Refer to Figures 15 and 16 for
descriptions of the various displayed information.
•
LCD Contrast Control: A trimpot control that adjusts the contrast of the LCD display. Use a small
flat blade screwdriver, insert into the CONTRAST control VR5 to the right of the display, and turn
clockwise to increase contrast.
•
ANT Button: Has two different functions based on the length of time you press and hold it before
releasing. Press [ANT] quickly (less than one second) to select the antenna bank to tune. Press
button to toggle between antenna banks 1 and 2. The Antenna indicator on the main display
indicates the selected antenna bank. Press and hold [ANT] for one second to cycle among the
four memory banks of the current antenna bank. The selected bank is indicated by a series of
short beeps, where one beep indicates bank A, two beeps indicate bank B, three beeps indicate
bank C, four beeps indicate bank D, and five beeps indicate antenna memory is OFF. The
Memory indicator on the main display also indicates the selected bank. Pressing the [ANT] button
switches the antenna bank or memory bank only when there is no RF power. Also, the tuner
setting for the selected antenna bank or memory bank, if available, is instantly restored from
memory when enabled.
•
MODE Button: Time-sensitive and used to navigate through the various main menus and to enter
or exit the setup menus.
•
C-UP and C-DN Buttons: Used to manually increase or decrease the capacitance of the L-
network matching circuit. The capacitance ranges are 0 to 3926 pF (picofarads) on the input side
and 0 to 976 pF on the output side. The upper limit of capacitance, dependent on frequency, is
used to limit the maximum voltage and current across the tuner’s components. This limit can be
removed in the LC Limit setup menu, but is not recommended.
Note: Pressing [C-UP] and [C-DN] simultaneously toggles the capacitor between the input and output
sides of the L-network. One beep when the capacitor is on the antenna side. Two beeps when the
capacitor is on the transmitter side.
•
L-UP and L-DN Buttons: Used to manually increase or decrease the inductance of the L-network
matching circuit. The inductance range is 0 to 24.28
µ
H (microhenries). The upper limit of
inductance, dependent on frequency, is used to limit the maximum voltage and current across the
tuner’s components. This limit can be removed in the LC Limit setup menu, but is not
recommended.
Note: Pressing [C-DN] and [L-DN] (both DOWN buttons) simultaneously places the tuner in bypass
mode. One beep sounds to indicate bypass mode. RF from the transmitter goes directly to the antenna
with no matching.
