I At-180 Internal Switch Description - Icom IC-703 Instruction Manual

15
OPTION UNIT INSTALLATIONS AND SETTINGS

I AT-180 internal switch description

The optional AT-180 has 3 operating conditions for HF
band operation. Select a suitable condition according
to your antenna system.
q Remove the top cover of the AT-180.
w Set the tuner switches to the desired positions ac-
cording to the table below.
SW Position
The tuner operating condition is set by S2
A
(default)
described below.
THROUGH INHIBIT
The tuner tunes the antenna even when the
antenna has poor SWR (up to VSWR 3:1
after tuning). In this case, manual tuning is
necessary each time you change the fre-
B
quency although the tuner automatically
starts tuning when the VSWR is higher than
3:1. This setting is called "through inhibit,"
however, the tuner is set to "through" if the
VSWR is higher than 3:1 after tuning.
TUNER SENSITIVE CONDITION
The tuner tunes each time you transmit (ex-
cept SSB mode). Therefore, the lowest
C
SWR is obtained at any given time.
For SSB mode, the same condition as the
"D" position.
NORMAL CONDITION
The tuner tunes when the SWR is higher
D
(default)
than 1.5:1. Therefore, the tuner activates
only when tuning is necessary.
• Specifications for the AT-180
• Frequency coverage : 1.9 – 54 MHz
• Input impedance
• Maximum input
power
• Minimum tuning
power
• Matching impedance : 16.7–150 Ω
range
• Tuning accuracy
• Insertion loss
• Power supply
requirements
• Dimensions
(mm/in)
• Weight
• Supplied accessories : coaxial cable
89
Operation
: 50 Ω
: 120 W
: 8 W
(HF band)
20 –125 Ω
(50 MHz band)
: Less than SWR 1.5:1
: Less than 1.0 dB
(after tuning)
: 13.8 V DC/1 A
(supplied from
the transceiver's ACC socket)
: 167(W) × 58.6(H) × 225(D)
(W) × 2 (H) × 8
9 5 7
6 ⁄ ⁄ ⁄ (D)
16 17 8
: 2.4 kg; 5 lb 4 oz
,
(1 m)
ACC cable
(DIN 13 pins)
• AT-180 inside top cover
S2 S1
D C B A
• Connector information for ACC(2) socket
2
5
4
3 ACC 2
1
6 7
PIN NO./
DESCRIPTION
NAME
Regulated 8 V output.
q 8 V
(10 mA max.)
w GND
Connects to ground.
Input/output pin.
e SEND
Goes to ground when transmitting (20 mA
max). When grounded, transmits.
Band voltage output.
r BAND
(Varies with amateur band; 0 to 8.0 V).
t ALC
ALC output voltage (–4 to 0 V).
y NC
No connection.
u 13.8V
13.8 V output when power is ON (1 A max).