Auto Antenna Tuner Operation - Kenwood TS-940S Instruction Manual

4. AUTO ANTENNA TUNER OPERATION
If the TS-940S is operated into an antenna with a high
SWR. the final stage SWR protection circuit may operate
(when SWR is greater than approximately 2 : 1 ). Use of
the AT-940 Automatic Antenna Tuner will help you to
match the antenna to the transceiver. The AT -940 is capa-
ble of matching a 20 - 150 ohm load, or approximately a
3 : 1 SWR. If the antenna and feed line exceed this range
the tuner may not be able to find the correct match. If the
tuner cannot match after two attemps, check your anten-
na and feed lines.
AT indicator
AUTO/THRU switch
Sub-display
AT. Tswitch
(a)
I
ANTENNA TUNER
AUTO TUNE READY
(b)
I
ANTENNA TUNER
TUNING····!!
(c)
I
TUNING FINISHED
TX-READY
(d)
I
ANTENNA TUNER
NO MATCH
18
Output power of the TS-940S will automatically be set to
approximately 1 0 watts during the tuning process to pro-
tect the finals against damage.
While the automatic antenna tuner is capable of reducing
the apparent SWR of the antenna system, it is important
to remember that maximum power output will only occur
when the antenna has been adjusted for the lowest possi-
ble SWR.
To operate the AT-940:
1. Set the AUTO/THRU switch to ON. The AT indicator will
light.
2. Press the AT.T switch. The LCD will display message (a),
for approximately 3 seconds.
3. While the "Tune Ready" message is appearing in the dis-
play, initiate transmit with the PTT switch, SEND switch,
or CW key, and the antenna tuner will begin tuning. The
message shown in (b) will appear in the LCD display to
confirm tuning is in progress.
4. When tuning has finished, message (c) will appear in the
LCD display.
5) If tuning cannot be accomplished within approximately 30
seconds after the beginning of the tuning process, the
message that appears in (d) will appear.
Switch to receive, wait a few moments, and then try
again. If no match can again be found, check your antenna
feedline, and antenna system
Note: -----------------------------------------
When adjusting an external antenna tuner, reduce the output
power of the TS-940S to approximately 50 watts. This will
provide adequate protection for the final amplifiers during
tuning.