Morse Code And Beeps; Transceiver Foldback Circuit - MFJ Legal Limit IntelliTuner -998RT Instruction Manual

MFJ-998RT Legal Limit IntelliTuner
matching. One beep indicates changing to bypass mode. Also, the decimal point in the SWR reading is
replaced with a comma.
Pressing [TUNE], [C-DN] and [L-DN] simultaneously overwrites the tuner memory with the current tuner
setting; settings with SWR greater than 3.0 will not be stored. One beep indicates memory overwrite.

Morse Code and Beeps

If not enough power is applied for tuning (less than five watts), the display will flash INCREASE POWER
three times and "QRO" (dah-dah-di-dah di-dah-dit dah-dah-dah) will be sent on CW. Increasing the input
power above five watts ends this message. When input power is too high, the tuner enters a self-
protection mode. 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, the tuner will cease the tuning routine, flash DECREASE
POWER three times and send "QRP" (dah-dah-di-dah di-dah-dit di-dah-dah-dit) on CW. 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 1500 watts is applied to the tuner, the tuner will
go into bypass mode, flash OVERLOAD three times and send "QRT" (dah-dah-di-dah di-dah-dit dah) on
CW. If the tuning process is activated under these conditions, the tuner will not start the tuning. It will
display a warning message on the LCD and send the appropriate code on CW. The following table shows
the various tuner beeps:
Function
Antenna Bank
Memory Bank
Bypass Toggle
Tuned SWR
TM
StickyTune
[TUNE]<0.5 sec.
Manual L/C Adjustment
Capacitors
Tuning Mode
Memory Overwrite
Amplifier Bypass
TM
Control
Disable Radio Interface
Delete Confirmation?
DELETE BANK
DELETE ANTENNA
TOTAL RESET

Transceiver Foldback Circuit

Modern transceivers with solid-state finals usually have a foldback circuit to protect the final transistors
from high SWR, which can damage or destroy them. A foldback circuit detects the SWR during transmit
and reduces the output power as the SWR rises above a preset threshold, usually 2:1. The higher the
SWR the lower the power is set to prevent damage. If your transceiver has a foldback circuit, you can
simply key down and tune at any power level from 5 to 100 watts. If your transceiver does not have a
foldback circuit, you must manually set the power level to 20 watts or less for tuning. At higher power
levels, the reflected power occurred during tuning can damage your transceiver and causes component
© 2011 MFJ Enterprises, Inc
TM
Automatic Remote Antenna Tuner
Indicates By One Beep
1
A B
1 Beep 2 Beeps 3 Beeps
Bypass Mode
(L=0 and C=0)
SWR SWR SWR
<1.5 <2.0 <2.5
1 Beep 2 Beeps 3 Beeps
ON
To Bypass
L/C at Lower Limit
Switch to Antenna Side
Automatic
X
ON
Yes
DELETED
Or
RESET
Figure 9 Beep Indicators
MFJ-998RT Version 1A
Indicates By Two Beeps
2
C D OFF
4 Beeps 5 Beeps
Restore Last L/C Setting
SWR SWR
<3.0 >3.0
4 Beeps "SWR"
OFF
To Tune
L/C at Upper Limit
Switch to Transmitter Side
Semi-Automatic
OFF
X
No
CANCEL
Instruction Manual
By Pressing
[ANT] <1 second
[ANT] >1 second
[TUNE] <0.5 seconds or
[C-DN]+[L-DN]
[TUNE] for 0.5-2 seconds
[TUNE] for 2-10 seconds
[TUNE] >10 seconds
[C-DN] or [L-DN]
[C-UP] or [L-UP]
[C-UP]+[C-DN]
[TUNE]+[ANT]
[TUNE]+[C-DN]+[L-DN]
[MODE]+[L-UP]+[L-DN]
[TUNE]+[MODE]+[POWER
]
[C-DN] for YES
Or
[L-DN] for NO
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