MFJ-998 Legal Limit IntelliTuner Automatic Antenna Tuner
Instruction Manual
©
2007-2010 MFJ Enterprises, Inc.
14
greater than 60 watts automatically sets the meter to the high power range. Forward power less than 250
watts and reflected power less than 40 watts automatically set the meter to the low power range. When
auto range is enabled, a two-dot vertical segment appears in the lower right corner of the Auto Range
indicator on the main LCD screen. Refer to Figures 16 and 17 for the on-screen Auto Range indicator.
SWR is calculated from the forward and reflected power
measurements as shown by the equation at the right. The SWR is
read from the 11 red SWR curves ranging from 1.0 to infinity by
observing the point where the forward and reflected power needles
cross on the red curved scales across the center of the meter. No
cumbersome or time-consuming SWR sensitivity adjustments are
required with this meter. Figure 12 shows an SWR of approx. 1.2.
The MFJ-998 also includes an SWR bar meter and an audio SWR indicator. It also has bar meters for
forward and reflected power.
The Menus
Main Mode Menus
The main mode menus show various tuner settings and status. There are four main mode menus arranged
in a “wrap-around” structure. When powered on, tuner operation starts with the main menu that was last
used. Within each main menu, press the [MODE] button briefly to view the next main menu. Press and
hold the [MODE] button for two seconds to enter the setup mode (see below). Various tuner indicators
are shown on all four main menus: Antenna 1/2,
IntelliTune
TM
, Radio Interface, Memory, LC Limit, Auto
Range, Auto/Semi, and
StickyTune
TM
. Refer to Figures 16 and 17 for details on the displayed
information.
Note: In sideband mode, the frequency readout on the tuner display jumps around to different
frequencies while transmitting and stops on another frequency when un-keyed. This is
normal and is a characteristic of sideband mode, because sideband signals jump around in
frequency and power.
Note: The decimal point in the SWR reading is replaced with a comma to indicate bypass mode.
Digital Wattmeter Menu
Shows the frequency, SWR, and forward and reflected power in watts.
Power Bar Meter Menu
Shows the frequency, SWR, forward power, and bar meters for forward and reflected power. The top bar
meter is the forward power and the bottom bar meter is the reflected power. The numeric reading of
forward power appears at the end of the bar meters. A power scale is printed just below the display on the
front panel. Each power bar meter consists of 60 bar segments. When in the high power range, multiply
the readings on the printed power scale by ten, and each vertical bar segment consists of three dots.
Below 1000 watts, each bar segment represents 20 watts; above 1000 watts, each bar segment represents
200 watts. The forward bar meter has a “peak hold” feature. The peak meter hold function (default)
freezes the highest displayed bar segment of the forward power for about one second, so that you can
more easily read the meter. This function can be turned ON and OFF in the Peak Hold setup mode.
reflected power
1
forward power
reflected power
1
forward power
SWR
+
=
−