16
FT-857 Operating Manual
L
INEAR
A
MPLIFIER
I
NTERFACING
The
FT-857
provides the switching and drive-control lines required for easy interfacing to
most all commonly-available amplifiers sold today.
These include:
r
The Antenna Jacks (“
HF/50MHz
” and “
144/430MHz
”);
r
A T/R control line (open circuit on RX, closure to ground on TX); and
r
A negative-going ALC jack (control voltage range: 0V to –4V DC).
r
When interfacing to the
VL-1000
Solid State 1 KW Linear Amplifier, the optional
CT-
58
Interface Cable provides for easy interconnection (requires that the Menu Mode
No-
020
[
CAT
/
LIN
/
TUN
]
setting changes to “
LINEAR
”).
The rear-panel
CAT/LINEAR
jack is an 8-pin, miniature DIN type, with the “TX GND” pin
providing a closure to ground on transmit, for T/R control of your linear amplifier. The
ACC
jack is a miniature stereo type, with external ALC input capability on the tip connection. The
main shaft is the ground return. The ring connection of the
ACC
jack, when closed to ground,
places the FT-857 into the transmit mode, and sends a steady CW carrier, for amplifier (or
antenna tuner) adjustment purposes.
Note that some amplifiers, particularly VHF or UHF “brick” amplifiers, offer two methods
of T/R switching: application of +13V or a closure to ground.
Be sure to configure your amplifier so that it switches via a closure to ground, as provided
by your
FT-857
’s
CAT
/LINEAR
jack (“TX GND” pin). Alternatively, many of these am-
plifiers use “RF Sensing” to control their relays; if yours is in this category, you may then use
the T/R control line from the “TX GND” pin
of the
CAT
/LINEAR
jack for control of your
HF linear amplifier, and RF sensing for your
VHF or UHF amplifier.
I
NSTALLATION
ANT 1
ANT 2
REMOTE
ON
OFF
BAND DATA 1
BAND DATA 2
GND
ALC 2
ALC 1
PTT 2
PTT 1
INPUT 1
INPUT 2
CONTROL
DC48V IN
T
o
H
F
A
n
te
n
n
a
T
o
H
F
A
n
te
n
n
a
T
o
5
0
M
H
z
A
n
te
n
n
a
IN
P
U
T
1
VL-1000
A
N
T
1
A
N
T
2
A
N
T
3
B
A
N
D
-D
A
T
A
1
C
A
T
/L
IN
E
A
R
T
o
1
4
4
/
4
3
0
M
H
z
A
n
te
n
n
a
A
L
C
1
CT-58 BAND DATA Cable
CT-58 ALC Cable
G
N
D
D
C
4
8
V
I
N
C
O
N
T
R
O
L
