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16
ANTENNA TUNER OPERATION
16-5
Operating the AT-180
D
Before operating
About using antenna:
1.
CAUTION:
•
NEVER
connect the antenna worth than 3:1 anten-
na. Even if the antenna tuner tune this antenna, it
causes to damage the antenna tuner.
•
NEVER
transmit with the tuner ON if no antenna is
connected. This will damage both the transceiver
and antenna tuner.
• Check the untuned antenna SWR. (Less than 3:1 for
the HF bands; Less than 2.5:1 for the 50 MHz band)
• Before start tuning, monitor the operating frequency
to make sure transmitting won’t cause interference to
other stations on the same frequency.
If the tuner cannot tune the antenna:
2.
❍
Check the untuned antenna SWR.
If its SWR is worth than 3:1, adjust the SWR.
❍
Check the transmit power.
If the transmit power is less than 8 W, adjust the RF
power on the Mic gain/RF power adjustment dis
-
play.
q
Push
MIC/RF PWR
(
C
) to open the MIC gain/RF
power adjustment display.
w
Rotate [BANK] (
L
) to adjust the RF power.
e
Push
MENU
(
C
) to close the display.
❍
Check the power source voltage/current capacity.
❍
If the tuner still cannot reduce the SWR to less than
1.5:1 after checking the above, perform the follow-
ing:
• Try manual tuning one or more times.
• Adjust the antenna feedline length. (This is effec
-
tive for higher frequencies in some cases.)
•
Even if manual tuning does not match the antenna
and the tuner turns OFF the first time, it may match
the antenna the second time.
❍
Tuning a narrow bandwidth antenna
Some antennas, especially for the low bands, have a
narrow bandwidth. These antennas may not be tuned
beyond the edge of their operating bandwidth, there-
fore, manually 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.
q
Select 3.55 MHz and hold down
TUNER/CALL
(
L
)
for 1 second to start manual tuning.
w
Select 3.80 MHz and hold down
TUNER/CALL
(
L
)
for 1 second to start manual tuning.
L
eft
R
ight
C
enter
D
isplay
The
L
,
R
,
C
or
D
in the
instructions indicate the
part of the controller.
L
: Left side
R
: Right side
C
: Center bottom
D
: Display (Touch screen)