Icom IC-7300 HF Plus Full Manual page 113

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11
ANTENNA TUNER OPERATION
About the internal antenna tuner
The internal automatic antenna tuner automatically
matches the transceiver to the antenna within the
range of 16.7 ~ 150 Ω (SWR of less than 3:1).
When the tuner has matched an antenna over some
period of operating time, latching relays of up to 100
combinations have been memorized as preset points.
If the frequency is tuned over ± 1.5% of the current
memorized frequency point, the tuner uses the relay
combinations of the next memorized point (if it is
within ± 1.5% of the new frequency). If there are no
memorized points with the range, the tuner switches
to bypass.
• When you install a new antenna, or you want to
change the antenna settings, you can clear the all
of the internal antenna tuner preset points with the
"<<Preset Memory Clear>>" item on the TUNER set
screen. (p. 12-5)
» SET > Function > Tuner >
MENU
<<Preset Memory Clear>>
• You can select whether or not to save the internal
antenna tuner's status after pushing
band in the "[TUNER] Switch" item on the TUNER
set screen.
(p. 12-5)
» SET > Function > Tuner >
MENU
[TUNER] Switch
NOTE: When the transceiver receives a strong physical
shock, some of the internal latching relays may unlatch. In
that case, push to turn OFF the tuner, then turn
TUNER
ON again to reset all the latching relays.
Internal antenna tuner operation
1. Push
2. Tune the antenna.
D Manual tuning
You can manually tune the antenna before
transmitting for the first time.
1. Hold down
2. After tuning, "TUNE" is displayed.
D PTT Tuner start
The tuner is always activated when PTT is pushed
after the frequency is changed (more than 1% from
last-tuned frequency). This function tunes the antenna
on each
TUNER
for the first transmission on a new frequency.
L This function can be turned ON in the "PTT Start"
NOTE: If the SWR is higher than about 1.5:1, hold down
TUNER
If the tuner cannot tune the antenna
• Repeat manual tuning several times.
• Even if the tuner cannot tune the antenna on the first
tuning, it may success at the second tuning.
• Some antennas, especially for the low bands, have a
narrow bandwidth. These antennas may not tune at
the edge of their bandwidth, therefore, tune such an
antenna as follows:
(Example):
Suppose you have an antenna which has an SWR of
1.5:1 at 3.55 MHz and an SWR of 3:1 at 3.8 MHz.
1. Set 3.55 MHz, and hold down
2. Set 3.80 MHz, and hold down
11-2
to turn ON the internal antenna
TUNER
tuner.
• "TUNE" is displayed when the tuner is ON.
L To tune the antenna, see "Manual tuning" or "PTT
Tuner start" below.
for 1 second to start manual
TUNER
tuning.
• The tuner reduces the SWR to less than 1.5:1 after
2~3 seconds of tuning.
L While tuning, a side tone is heard and "TUNE" blinks
red.
L If the tuner cannot tune, "TUNE" disappears and the
tuning circuit is automatically bypassed
item of the TUNER set screen.
» SET > Function > Tuner > PTT Start
MENU
for 1 second to start manual tuning.
second to start manual tuning.
second to start manual tuning.
(p. 12-5)
for 1
TUNER
for 1
TUNER