MFJ-991 / MFJ-994 IntelliTuner Automatic Antenna Tuners
Instruction Manual
©
2004 MFJ Enterprises, Inc.
12
Tuner Status Indicators
If not enough power is applied for tuning (less than 5 watts for MFJ-991, 10 watts for MFJ-994), the
Forward Power needle will bounce to the 100-watt mark. When input power is too high, the tuner enters
a self-protection mode and the Forward Power meter needle bounces to 300 watts (full scale). The tuner
will not allow any of its relays to change. This feature is to prevent damage to your tuner.
If too much power is applied when tuning is in progress, the tuner will cease the tuning routine, and the
Forward Power meter needle will bounce to full scale. This occurs when the forward power exceeds 75
watts and the SWR is greater than 3.0, or when the forward power exceeds 125 watts regardless of the
SWR. If more than 150 watts (600 watts for MFJ-994) is applied to the tuner, the tuner will go into
bypass mode; both Forward and Reflected meter needles will bounce to full scale.
Default
Tuner Status
Button Action
Meter Needles
Stationary Needle Reads
Meter Range 30 watts
[TUNE] + [L-DN]
30 W Forward
*
Meter Range 300 watts
[TUNE] + [L-DN]
300 W Forward
*
*
Auto Range OFF
Sticky Tune OFF
Auto Tune SWR +0.5
[TUNE] + [C-DN]
[TUNE] 2 seconds
[TUNE] + [L-UP]
5 W Reflected
*
Auto Tune SWR +1.0
[TUNE] + [L-UP]
20 W Reflected
Auto Range ON
Sticky Tune ON
Auto Tune SWR +1.5
[TUNE] + [C-DN]
[TUNE] 2 seconds
[TUNE] + [L-UP]
60 W Reflected
Both Needles – Stationary
NO, do not delete
[L-UP]
0 scale
Confirm
Delete
N/A
Mid-scale
YES, delete
[C-UP]
Full scale
*
Target SWR 1.5
[TUNE] + [C-UP]
Needles intersect at SWR 1.5
Target SWR 2.0
[TUNE] + [C-UP]
Needles intersect at SWR 2.0
Bouncing Needle Reads
*
Capacitor on Transmitter side
[C-UP] + [C-DN]
30 watts Forward
Insufficient power to tune
(MFJ-991: Forward < 5 watts)
(MFJ-994: Forward < 10 watts)
[TUNE]
100 watts Forward
Too much power to tune
(Forward > 75 watts and SWR > 3)
or (Forward > 125 watts)
N/A
300 watts Forward
Capacitor on Antenna side
[C-UP] + [C-DN]
5 watts Reflected
*
Bypass Mode (L = 0 and C = 0)
[C-DN] + [L-DN]
20 watts Reflected
L or C at its limit
during manual adjustment
[C-UP], [C-DN],
[L-UP] or [L-DN]
60 watts Reflected
Both Needles – Bouncing
Input Power Overload
(MFJ-991: Forward > 150 watts)
(MFJ-994: Forward > 600 watts)
N/A
Full scale
Table 2. Meter Needle Codes.
Summary of Contents for IntelliTuner -991
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