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This way, at the end of the matching cycle, the necessary combination of relays to achieve the matching of
the connected antenna impedance to 50 Ohm is found. At the end of the cycle, this relay combination is
stored in the tuner nonvolatile memory. The stored values are organized in memory by the boundaries of
the frequency segments, in separate tables, by antenna number and type of selectivity. The stored data is
used later for quick tuning (see Section
operate with the same antenna and in the same frequency segment.
The basic cycle of a full (user) tuning may have different duration, depending on the value of the particular
antenna impedance, but the tuning time will never exceed 5 seconds.
5.2. Operator Actions for a Full Tuning Cycle
If you use more than one antenna for a specific band, you should select the desired
antenna for the operating frequency before starting the tuning cycle.
5.2.1. Full Tuning for Transceivers with CAT
When the capabilities of modern transceivers with CAT control are used, no manual operations for
transceiver control when performing full tuning cycle are required; the transceiver even restores the previous
operating mode afterwards. The operator should only do the following:
- Select the new frequency in receive mode;
- Change the antenna immediately, if another antenna is required (if there is more than one
antenna assigned for the selected band);
- Briefly press the TUNE button at the specified frequency and antenna.
The transceiver, amplifier, and tuner then perform in sync all necessary operations which would be
performed for a manually controlled transceiver, but with CAT this is done automatically, quickly, and
transparently. The amplifier remains in STBY mode throughout the tuning. At the end of the cycle, the state
of the transceiver and amplifier before the tuning cycle initialization is restored (modulation mode, power,
OPER/STBY, etc.).
5.2.2. Full Tuning for Transceivers without CAT Capability
To complete the same cycle of full tuning of the tuner with a transceiver without CAT connected, the operator
should proceed as follows:
- Select the new frequency of the transceiver in receive mode;
- Select a constant carrier mode for the transceiver (e.g., CW or FSK);
- Adjust the RF power of the transceiver to approximately 25 W (unless previously adjusted). You
may apply more power to compensate RF losses if the coaxial cable to the tuner is too long.
Page 42 of 72 | S e c t i o n BASIC FULL TUNING CYCLE
User's Manual | ACOM 04AT | Remote Automatic Antenna Tuner and Switch
4.4 Quick Tuning and Non-Volatile Memory
), when it is required to
May 2021
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