Acom 2020S, User Manual, Page: 35 / 76

User's Manual | ACOM 2020S | 1.8-54 MHz Linear Power Amplifier
June 2022 S e c t i o n FIRST POWER-ON, CONTROL SYSTEM, AND INITIAL CHECK | Page 35 of 76
b) Check-up in STANDBY mode
Turn the amplifier on, as described in Sections
3.1 Low Energy STANDBY Mode of the Power Supply
through
3.4 Basic Screen
(see
Figure 3-2 | Basic screen
).
Make sure that the amplifier is in STANDBY mode. Push the
OPR/STB button if needed to change to STB.
Repeat receive and transmit tests the same way you just did with the amplifier turned off but in STANDBY
mode now. During these tests note also whether the forward and reflected power bar graph and digital
readout (see Sections
3.4.e) Forward power bar-graph and digital readout
and
3.4.f) Reflected power bar-graph
and readout
), show respective RF power presence. If the reflected power exceeds the forward power, verify
that the input and output coaxial cables to the amplifier are not interchanged (see Sections
2.4.1.d) RF
INPUT connector
and
2.4.1.e) RF OUTPUT connector
, and
Figure 2-3 | Amplifier rear panel - Connections
, Pos. (d)
and (e)),
The power indication accuracy is optimized around the 1500 W level and usually it is
unreliable below 50 W.
c) Entering OPERATE mode
Entering the OPERATE mode the transceiver receiving should not suffer. If it worsens and besides the
indicator RX changes into TX although the transceiver is in receive mode, check the control cable connected
to the
KEY-IN input (see Section
2.4.1.b) KEY-IN connector
and
Figure 2-3 | Amplifier rear panel - Connections
,
Pos. (b)) for a short circuit. A wrong connection to the transceiver could cause the same problem.
d) Test transmission with the amplifier
If not readily set by CAT, switch the amplifier to the same band as the transceiver and antenna.
Set the transceiver to a continuous carrier mode and minimum power. In OPERATE mode choose a free
frequency and push the PTT or CW key briefly, while watching the amplifier's behavior:
•
RX mode must change to TX;
•
The reflected power must read below 20 W;
•
The forward power must read between 60 and 120 W with 5 W drive power from the
transceiver;
If the above test goes normally, push briefly the PTT once again, this time watching the transceiver's SWR
reading (i.e., the input SWR of the amplifier) - this must be below 1.2.
If the SWR to the transceiver is higher than 1.2, check the coaxial cable between transceiver's output and
amplifier's input socket (see Section
2.4.1.d) RF INPUT connector
and
Figure 2-3 | Amplifier rear panel -
Connections
, Pos. (d)).