Acom 500S, User Manual

Page: 31 / 66

User's Manual | ACOM 500S | 160-4 m Linear Power Amplifier
March 2023 S e c t i o n FIRST POWER-ON, CONTROL SYSTEM, AND INITIAL CHECK | Page 31 of 66
•
Check the good working order of the coaxial cables, connectors, and feed lines from the
transceiver antenna connector through the amplifier, the antenna switch or external tuner (if
there is one) to the BALUN transformer, and the antenna itself (see Section
2.4.f) RF OUTPUT 2
connector
).
If the power and SWR are as expected, transmit again and while watching the power and the SWR readings,
increase transceiver power gradually from minimum to maximum (but not more than 200 W in order to not
overload the RF by-pass circuit in the amplifier).
If SWR remains below 2:1 (preferably below 1.5:1) at the last test, decrease the power from the transceiver
to minimum again and continue with the next check-up.
b) Check-up in STANDBY mode
Turn the amplifier on, as described in Sections
3.1 Low Energy Standby Mode of the Power Supply
,
3.2 Front Panel
,
3.3 Initial Turning On
and
3.4 Basic Screen
(see
Figure 3-2 | Basic screen
).
Make sure that the amplifier is in STAND-BY mode. Push the
OPR/STB button if needed to change to STB.
In the USER PREFERENCES menu, unassign the ACOM tuner (if connected) in order to select the
RF OUTPUT 2
where the antenna was connected at the previous test (above point (a)).
Repeat receive and transmit tests the same way you just did with the amplifier turned off. 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
digital 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 Section
2.4.d) RF INPUT
and
2.4.f) RF OUTPUT 2
connector
).
The power indication accuracy is optimized around the 500 W level and usually it is
unreliable below 40 W.
c) Entering OPERATE mode
At OPERATE mode the transceiver receiving should not suffer. If it worsens and together with this the
amplifier 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.b) KEY IN
) 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, set the amplifier to the same band as the transceiver and antenna (see Section
3.5.1 OPR/STB and BAND buttons
).
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: