General Information; Introduction And Description - Acom Owner's Manual

User's Manual | ACOM 04AT | Remote Automatic Antenna Tuner and Switch

1. GENERAL INFORMATION

Congratulations on purchasing one of the finest antenna tuners in the world today.
ACOM is pleased that you have chosen one of our products, and we will endeavor to provide you with the
information and support you need to enjoy your purchase for many years.
We urge you to read all of the following materials before you embark on operating your new antenna tuner.

1.1. Introduction and Description

This manual explains:
Installation
•
Operation and
•
Maintenance
•
of the ACOM 04AT remote automatic antenna tuner for HF + 6 m with integrated four-way antenna switch.
The ACOM 04AT tuner is specifically designed and developed to work exclusively with the ACOM series of
solid state (transistor) amplifiers, e.g., ACOM 700S or ACOM 1200S.
It automatically selects one of four available antenna outputs (as assigned in bands by the operator) and
matches the impedance of the chosen antenna output by transforming it to 50 Ohm with SWR below 1.5:1
at the tuner input (typically below 1.3), providing an optimum load impedance for the amplifier.
Any necessary readjustments are swift, following the frequency changes and antenna selections.
The tuner matches all load impedances presenting a SWR below 3:1, regardless of phase angle, in a
continuous frequency range of 1.8-30 MHz and 50-54 MHz. In many cases, the tuner will match loads with
higher SWR (up to 10:1) as well, however a reduction in power may be necessary if the protective functions
of the tuner activate due to high values of SWR, current, voltage, forward or reflected power at the antenna
output.
Provided the SWR of the feedline/antenna system is up to 3:1, the tuner can handle input power levels up to
1200 W (PEP, mean or continuous carrier), regardless of the operating communication mode. For
feedline/antenna system SWRs between 3:1 and 10:1, the maximum permissible power at the tuner input is
gradually reduced down to 200 W at SWR=10:1 (see
), allowing for operation within tuner component specifications.
the antenna SWR
The tuner can be installed both in the shack and in a remote location, e.g., in a separate room, in a sheltered
location outdoors or even out in the open, close to the antennas, so that any feedlines from the unit to the
antennas, working in mismatched conditions, are kept as short as practically possible to avoid unnecessary
losses.
Generally, a remote installation of the tuner is preferable to a local one, because it reduces RF losses in most
of the feedline's length. Thanks to the built-in automatic antenna switch, a significant reduction in both
installation effort and required cable length can be achieved (up to three times the feedline length with four
antennas and in-shack tuner installation).
May 2021
Table 8-1 Maximum input power of the tuner as function of
S e c t i o n GENERAL INFORMATION | Page 9 of 72