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If there is no tuning setting stored in the memory, the tuner automatically stays in BYPASS mode and the
operator can proceed in either of the following ways:
- Start a full tuning cycle by briefly pressing the TUNE button (see Section
);
CYCLE
- Change the frequency and/or antenna to find a stored tuning setting from the tuner nonvolatile
memory.
Organization and use of the tuning settings memory
We recommend preparing custom tuning settings for the frequencies and antennas that will be used most
frequently. They will be automatically stored in the tuner memory, and automatically retrieved when a
frequency and/or antenna is changed.
The tuner memory is divided into four large groups - one per each antenna number. Each group is additionally
divided into 4 subgroups for the four degrees of selectivity (Sharp, Regular, Wide and Fixed). The number of
segments in each band increases with selectivity (sharpness degree - S, R, W, F, see Section
type / Rate (Selectivity Degree, Sharpness)
frequency, aiming same relative coverage on all bands (narrower at the LF end and wider at the HF bands).
Retrieving tuning settings from the memory is much faster than the main cycle of full tuning, with no
emissions of RF power. However, in the meantime the antenna may have changed its parameters to a smaller
or larger degree, so an old tuning may be ineffective and may need to be refreshed through a new cycle of
full tuning.
If the conditions at the antenna have changed since the time the tuning was memorized,
using outdated tuning settings may lead to a high SWR at the amplifier end. We
recommend updating the tuning settings with the TUNE button in this case.
For the purpose of quick tuning without CAT, the operator should adhere to the following rules of operation
for frequency and/or antenna change:
- Frequency segments can only be changed during reception using the
buttons or by sending a short preliminary transmission. Start the main transmission after a pause of at least
0.5 seconds.
- The pause between the short and the main transmission is needed so that the amplifier can first
check the new operating frequency and switch its harmonic filters, if necessary, to send a "quick tuning"
command to the tuner (possibly with a new antenna), to evaluate the response from the tuner and to refresh
the onscreen indication.
Page 38 of 72 | S e c t i o n STARTING UP AND MAIN FUNCTIONS
User's Manual | ACOM 04AT | Remote Automatic Antenna Tuner and Switch
). For each of the four degrees the segments width increases with
NOTICE
5 BASIC FULL TUNING
4.1 What is tuning
SEGMENT or SEGMENT
May 2021
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