Antenna Change; Tuning - Acom 1500 User Manual

User's Manual | ACOM 1500 | HF + 6 m Linear Amplifier

4.3. Antenna Change

By pressing the ANT button, the amplifier output can be switched between three antenna outputs. The
three lights above the button indicate the current antenna selection.
To avoid damage (not covered under warranty) do not change antennas while
transmitting. Do not transmit into an antenna output (1, 2, or 3) if it is not connected to
an antenna or a dummy load.
Selection of any of the antenna outputs can be disabled if not used (see Section
Antenna Output Assignment
outputs, preventing no-load transmission and possible amplifier damage (not covered
under warranty).

4.4. Tuning

Tuning is possible only in the OPERATE mode.
Press the OPER button in order to illuminate its LED (unless AUTO-OPERATE is active).
a) Preliminary information
Tuning the amplifier involves a procedure of matching the impedance of the currently used antenna and
transmission line to the amplifier tube's optimum characteristic load resistance. This will ensure maximum
plate efficiency and optimum RF gain at nominal output power, with minimal distortion and spurious
output.
Note that REFLECTED POWER readings and the measured SWR depend on the antenna and transmission
line impedance only, and not on amplifier tuning. If the load impedance is not a nominally resistive
50-Ohms, the REFLECTED POWER indicator will always show a reading, no matter what the tuning settings.
Proper tuning is always necessary, however, and will allow you to operate at a high power level, without
distortion or any danger to the amplifier.
August 2021
NOTICE
NOTICE
). This prevents inadvertent selection of unused antenna
5.3
S e c t i o n OPERATION | Page 25 of 52