MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner
Instruction Manual
©
2007-2010 MFJ Enterprises, Inc.
6
•
Analog Meter Full Scale Adjustment:
Two trimpots, located to the left of the LCD display,
calibrate the full scales of the forward and reflected needles. The small hole on the top adjusts the
forward needle and the small hole on the bottom adjusts the reflected needle. See “Analog Meter
Calibration” section on page 29 for the calibration procedure.
•
LCD Display:
A 2-line by 16-character alphanumeric display with backlight. 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 16 and 17
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 small hole 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 toggle between
Antenna 1 and Antenna 2.
The Antenna indicator on the main display indicates the selected antenna. A single-wire antenna is,
by default, Antenna 1.
Press and hold [ANT] for one second to cycle among the four memory banks of the current antenna.
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 or bank
only
when there is no RF power. Also, the
tuner setting for the selected antenna or 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] simultaneously places the tuner in bypass mode. One beep
sounds to indicate bypass mode, and RF from the transmitter goes directly to the antenna
with no matching.
