User's Manual | ACOM 2020S | 1.8-54 MHz Linear Power Amplifier
Page 38 of 76 | S e c t i o n OPERATION
June 2022
4.
OPERATION
4.1.
Change of Modes RX/TX and OPERATE/STANDBY; AUTO OPERATE User Settings
a)
STANDBY mode
In STANDBY 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 follows the
KEY-IN
input unconditionally (see
, Pos. (b, c)).
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 STANDBY 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 required 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
Figure 2-3 | Amplifier rear panel - Connections
, Pos. (c)) follows
the
KEY-IN
input only after all conditions for safe transmission have been found good by the amplifier
control unit. When used, the
KEY-OUT
output duly disables transmission while the amplifier is not ready.
The two modes OPERATE and STANDBY may be changed in either way:
•
Manually (locally) - by pressing the OPR/STB button alternatively (see
Pos. 1);
•
Automatically at a SOFT FAULT protection trip - when the AUTO OPERATE user setting is
activated (see Section
4.1.c) AUTO OPERATE user settings
Access to the OPERATE mode can be locked in the AMP SERVICE menu, the OPERATE
ACCESS user setting (see Section
and