USING THE AUTOMATIC ANTENNA TUNER
ABOUT ATU OPERATION
Figure 1 depicts a situation where normal tuning via 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 has become appeared. The operator presses and holds in the [TUNE] button for two seconds to begin impedance matching using the ATU.
If a high SWR conditions exists (above 3:1), corrective action must be taken in the antenna system to bring the impedance closer to 50 Ohms. Besides the fact that 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 feed system, and such failures can lead to the generation of spurious signals causing TVI, etc.
SWR: 2.0
Feed Point SWR
SWR: 1.5
SWR: 1.0
Frequency 
SWR after ATU Tuning
FIGURE 1
The “ 
” icon appears on the display when you transmit on this frequency
Memorized ATU Tuning
SWR: 3.0
SWR: 3.0
SWR: 2.0
Retuned Setting
SWR: 1.0
Frequency 
FIGURE 2
About ATU Memories
SWR
The tuning settings are committed to the ATU memory.
SWR
Tuning data will not be retained in memory. If you return to the same frequency, the tuning process must be repeated.
SWR
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.
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