Acom 500S, User Manual

Page: 34 / 66

User's Manual | ACOM 500S | 160-4 m Linear Power Amplifier
Page 34 of 66 | S e c t i o n OPERATION March 2023
4. OPERATION
4.1.
Change of Modes RX/TX and OPERATE/STANDBY; AUTO OPERATE User Setting
a) STANDBY mode
In STANDBY mode, as well as when the amplifier is not powered, 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
2.4.c) KEY OUT
connector
) follows the KEY IN input unconditionally. The bands cannot be changed neither manually nor by
CAT or remotely.
Receiving and transmitting with the transceiver (no more than 200 W) is done through RF bypass path from
RF INPUT to RF OUTPUT 2 when the amplifier is not powered. In STANDBY mode, either RF OUTPUT 1 or
RF OUTPUT 2 of the amplifier can be used (see Section
4.3.a) Antenna Change
).
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 as with amplifier in STANDBY mode;
•
At grounded KEY IN (OPERATE/TX mode) the RF drive is amplified and fed to the selected
antenna (see Section
4.3 Antenna Change
).
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
2.4.c) KEY OUT connector
) 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 transceiver transmission while the amplifier is not ready.
The two modes OPERATE and STANDBY may be changed in three ways:
•
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
).