Page 73FTDX5000 OPERATING MANUAL
ABOUT ATU OPERATION
Figure 1 depicts a situation where normal tuning of the ATU has been successfully completed, and the tuning data has been
stored in the ATU memory. The antenna system as seen by the transmitter is shown.
In Figure 2, the operator has changed frequency, and the “ ” icon is shown. The operator presses and holds in the
[
TUNE
]
button for two seconds to begin impedance matching using the ATU.
If a high SWR condition exists (above 3:1), corrective action must be taken in the antenna system to bring the impedance
closer to 50 Ohms. The ATU will refuse to memorize settings on frequencies where the SWR exceeds 3:1. The high SWR
may indicate a mechanical failure in the antenna or feed system, and such failures can lead to the generation of spurious
signals causing TVI, etc.
About ATU Memories
SWR (Post-tuning) Less than 1.5:1
The tuning settings are committed to the ATU memory.
SWR (Post-tuning) Greater than 1.5:1
Tuning data will not be retained in memory. If you return to the same frequency, the tuning process must be repeated.
SWR (Post-tuning) Greater than 3:1
The “ ” icon will light up, and tuning settings, if achieved, will not be memorized. Please investigate and
resolve the high SWR condition before attempting further operation using this antenna.
USING THE AUTOMATIC ANTENNA TUNER
SWR: 2.0
Frequency
SWR: 1.5
Feed Point SWR
SWR after ATU Tuning
SWR: 1.0
FIGURE 1
FIGURE 2
SWR: 3.0
SWR: 3.0
Frequency
SWR: 2.0
Memorized ATU Tuning
Retuned Setting
SWR: 1.0
The “ ” icon appears on the display
when you transmit on this frequency
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