About Atu Operation - Yaesu FTDX9000D Operation Manual

U
SING THE
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 HI SWR LED has become illuminated. The operator presses and
holds in the TUNE switch 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
SWR = 1.5
SWR = 1.0
SWR = 3.0
SWR = 2.0
SWR = 1.0
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 HI SWR LED 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. 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.
FT 9000D O
DX PERATION
A
UTOMATIC

About ATU Operation

Feed Point SWR
Frequency
©
SWR Seen by ATU
Figure 1
Memorized SWR
①
Frequency
©
Figure 2
About ATU Memories
M
ANUAL
A
NTENNA
Retunig
②
T
UNER
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