Changing Frequencies And Antennas; Specifics Of Operation In Transmission Mode; Power Reduction At Overload - Acom 04AT Operating Manual

the antenna assignments by bands or as a manual switch, if more than one antenna is
assigned per band.
The tuner stays in BYPASS state until reactivated by pressing and holding the TUNE
button again (1s – Use ATU). Regardless of whether or not a frequency and/or an-
tenna were changed in the meantime, a new quick tuning is completed from the tuner
memory for the current antenna and frequency in use. If there is no stored tuning in the
tuner memory, the tuner will stay in BYPASS mode until it is tuned.

4.6 CHANGING FREQUENCIES AND ANTENNAS

Changing a frequency segment or band with a respective quick tuning can be per-
formed in three ways:
- Automatically – utilizing transceiver CAT.
- Semi automatically (when no CAT is active) – by a short transmission at the new
frequency, followed by a short pause, during which "quick tuning" will be completed
(S. 4.4).
- Manually – by pressing the
an active CAT) or by changing the antenna with the ANT button (only if more than
one antenna was declared for the operating frequency (S. 6.1). The last used an-
tenna is memorized.
The frequency segment (boundaries of validity of the current tuning) is numerically
indicated on the basic screen of the amplifier, above the tuner setting area. If the new
frequency is outside the current frequency segment, a quick tuning will be performed.
If the tuning found in memory is too old, the operator will see the message "WARNING:
TUNING OUTDATED" (see S. 4.4 and 6.2.8).

4.7 SPECIFICS OF OPERATION IN TRANSMISSION MODE

Under no circumstances should operation with antenna
output SWR above 10:1 be allowed!
In many cases, the tuner may be able to handle SWR even higher than 3:1 at the
antenna output, but if the protection for antenna overcurrent, overvoltage, forward or
reflected power is activated, the operator should reduce power input to the tuner (e.g.
transceiver excitation).

4.8 POWER REDUCTION AT OVERLOAD

When matching of loads with SWR above 3:1 (up to 10:1) is possible, the maximum
allowed tuner power must be reduced gradually as per Table 8.1.
SEGMENT or SEGMENT  button (unless there is
CAUTION
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