Specifications

16 FT-857D Operating Manual
LINEAR AMPLIFIER INTERFACING
The FT-857D provides the switching and drive-control lines required for easy interfacing
to most all commonly-available amplifiers sold today.
These include:
 The Antenna Jacks (“HF/50MHz” and “144/430MHz”);
 A T/R control line (open circuit on RX, closure to ground on TX); and
 A negative-going ALC jack (control voltage range: 0V to –4V DC).
 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 connec-
tion. 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-857D’s CAT/LINEAR jack (“TX GND” pin). Alternatively, many of these
amplifiers 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.
INSTALLATION
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
To HF Antenna To HF Antenna To 50 MHz Antenna
INPUT 1
VL-1000
ANT 1 ANT 2 ANT 3
BAND - D ATA 1
CAT
/LINEAR
To 144 / 430 MHz Antenna
ALC 1
CT-58 BAND DATA Cable
CT-58 ALC Cable
GND
DC 48V IN
CONTROL