Acom 2020S - Operation; Change of Modes RX;TX and OPERATE;STANDBY; AUTO OPERATE User Settings

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 Figure 2-3 | Amplifier rear
panel - Connections, 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 output (see 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 Figure 3-2 | Basic screen,
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 5.1 Menu USER PREFERENCES and 5.1.c) OPERATE ACCESS).