Acom ACOM 04AT, Operating Manual

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4.3 TUNING MODES: FULL, QUICK AND BYPASS
The tuner can operate in two main modes of tuning: full and quick. In addition, the tuner
can be switched to BYPASS mode, without tuning. This is a non-basic mode, but it can
be useful.
- “Full tuning” is the basic cycle for active searching the relays setup for a new fre -
quency and antenna, see details in S. 5.
- “Quick tuning” passively retrieves information stored in the tuner non-volatile mem -
ory of full tuning settings prepared earlier – see S. 4.4.
- “BYPASS” mode eliminates the action of the coils and capacitors in the matching
network of the tuner in order to be able to change frequency segments or bands
without retuning, e.g. at broad-band or preset antenna – see S. 4.5. In addition to
operation, the BYPASS mode can be used for diagnostics and maintenance of the
antenna-feeder path – See S. 7.4.
4.4 QUICK TUNING AND NON-VOLATILE MEMORY
Quick tuning is performed automatically at each change of frequency segment, band
and/or antenna. The tuner checks if there is a stored tuning setting for the desired fre -
quency and antenna in the non-volatile memory. If there is none, the tuner automatical-
ly stays in BYPASS mode and the amplifier displays the warning message ATU FULL
TUNING REQUIRED.
If there is a stored setting, the tuner reads the relay combination settings from its non -
volatile memory and immediately performs it by switching all relays in one step (and if
necessary, switches the antenna as well) without any emission. The amplifier refresh -
es its indication – the new frequency segment is enclosed in a thin orange frame on
the frequency range, “Memory settings” is displayed in front of the numerical segment
boundaries and the number, type, and name of the antenna in use are updated. At this
moment the amplifier is ready for transmission.
If the tuning found in memory is too old, the alarm message TUNING OUTDATED is
displayed (see S. 6.2.8), but the outdated tuning setting can still be used. If the opera -
tor wants to refresh it, he can immediately start a new full tuning cycle and the data in
the non-volatile memory will be refreshed and the message will disappear.
If there is no tuning setting stored in the memory, the tuner automatically stays in BY-
PASS mode and the operator can proceed in either of the following ways:
- Start a full tuning cycle by briefly pressing the TUNE button (see S. 5).
- Change the frequency and/or antenna to find a stored tuning setting from the tuner
nonvolatile memory.