Icom IC-7300 HF Plus Full Manual page 114

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11
ANTENNA TUNER OPERATION
About an external antenna tuner
The optional AH-4
antenna tuner
7300 to a long wire antenna more than 7 m/23 ft long
(3.5 MHz and above).
During mobile operation, the optional AH-2b
matches the IC-7300 to a whip antenna more
element
than 2.5 m/8.2 ft long (7
The optional AH-740
automatic tuning antenna
covers 2.5 to 30 MHz range with a supplied whip
antenna.
R DANGER HIGH VOLTAGE!
NEVER touch the antenna element while tuning or
transmitting. Always install it in a secure place.
NEVER operate the AH-4 or AH-740 without an antenna
connected. The tuner and transceiver will be damaged.
D Using the AH-4 or AH-740
1. Turn ON the transceiver.
• "TUNE" is displayed.
L Each time you push
or goes out, and the AH-4 or AH-740 is turned ON or
OFF (bypassed).
2. Hold down for 1 second to start manual
TUNER
tuning.
• The tuner reduces the SWR to less than 2:1 after 2~3
seconds of tuning.
L While tuning, a side tone is heard and "TUNE" blinks
red.
L If the tuner cannot reduce the SWR to less than 2:1
after 15 seconds of tuning, "TUNE" goes out.
3. After tuning, "TUNE" is displayed.
L When the long wire antenna cannot be tuned, "TUNE"
goes out. In that case, the AH-4 is bypassed and the
wire is directly connected.
NOTE: When the wire antenna cannot be tuned, confirm
wire length and connection.
Note that the AH-4 cannot tune a wire that is a ½λ long or
on a multiple of that frequency.
matches the IC-
antenna
50 MHz).
~
,
"TUNE" is displayed
TUNER
D Using an external antenna tuner
When you use a non-Icom external antenna tuner,
be sure to turn OFF the internal antenna tuner before
connecting the external antenna tuner.
Otherwise, the tuning may fail because both antenna
tuners (internal and external) will simultaneously start
tuning.
See the antenna tuner's instruction manual for details.
NOTE: Be sure not to connect the antenna tuner without
an antenna connected. This could damage the transceiver
or external antenna tuner.
TIP: If the SWR is not reduced to 2:1 after retuning, see
"If the tuner cannot tune the antenna" (p. 13-2) for details.
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