User's Manual | ACOM 1200S | 1.8-54 MHz Linear Power Amplifier
S e c t i o n FIRST POWER-ON, CONTROL SYSTEM, AND INITIAL CHECK | Page
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• Check again whether the power control is set at minimum;
• Check whether the frequency is within the operating range of the selected antenna;
• Check the good working order of the coaxial cables, connectors, and feed lines from the
transceiver antenna jack 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.e) RF OUTPUT
socket).
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 of the amplifier).
If SWR remains below 2 (preferably below 1.5) 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 without ACOM 04AT antenna tuner
assigned).
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 bargraph and digital readout and 3.4.f) Reflected power bargraph
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.d) RF INPUT
socket and 2.4.e) RF OUTPUT socket).
The power indication accuracy is optimized around the 1000 W level and usually it is
unreliable below 50 W.
c) Entering OPERATE mode
At 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.b) KEY-IN socket) for a short circuit. A wrong connection to the transceiver
could cause the same problem.
d) Test transmission
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:
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