Acom 700S, User Manual, Page: 27 / 52

User's Manual | ACOM 700S | 1.8-54 MHz Linear Amplifier
May 2021 S e c t i o n OPERATION | Page 27 of 52
4. OPERATION
4.1.
Change of Modes RX/TX and Operate/Stand-by; AUTO OPERATE user setting
a) Stand-by mode
In Stand-by mode, as well as when the amplifier is not powered, receiving and transmitting (no more than
200 W) with the transceiver is done via RF bypass between RF INPUT and RF OUTPUT of the amplifier. In
Standby, the transceiver's RF power is not amplified, the control KEY-IN input does not affect the operation,
and the KEY-OUT output (see Section
2.3.c) KEY-OUT socket
) follows the KEY-IN input unconditionally. The
bands cannot be changed neither manually nor by CAT or remotely.
b) Operate mode
In Operate mode the receive-transmit (RX/TX) direction is controlled by the KEY-IN input:
•
At open KEY-IN (Operate/RX mode), the transceiver receives the signals from the antenna
through the same RF by-pass path between RF INPUT and RF OUTPUT as with amplifier
turned off or in Stand-by mode;
•
At grounded KEY-IN (Operate/TX mode) the RF drive is amplified and fed to the antenna
through the RF OUTPUT connector.
In order to provide time for the relays to switch safely from receive to transmit, the
transceiver should provide a dead time i.e. must "notify" the amplifier in due time by
grounding the control KEY IN input not later than 10 ms before feeding drive power
toward the amplifier RF input. Otherwise, the protection system will read "HOT
SWITCHING ATTEMPT" and will trip off.
In Operate mode the KEY OUT output (see Section
2.3.c) KEY-OUT socket
) follows the KEY-IN input only after
all conditions for safe transmission have been found good by the amplifier control unit. The KEY OUT
output duly disables transmission while the amplifier is not ready.
The two modes
Operate and Stand-by may be changed:
•
Manually (locally) - by pressing the OPR/STB button alternatively (see
Figure 3-2 Basic screen
);
•
Automatically at a SOFT FAULT protection trip - when the AUTO OPERATE user setting is
activated (see Section
5.4.c) AUTO OPERATE
);
•
By a remote control command.
Access to the Operate mode can be locked in the AMP SERVICE menu, the OPERATE
ACCESS user setting (see Section
5.2 Menu AMP SERVICE (Amplifier Service Functions)
and
Figure 5-3 Menu AMP SERVICE
).