About Atu Operation - Yaesu FT-450D 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 "
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. A High SWR may indicate a mechanical failure in the feed system, and can lead to the generation
of spurious signals causing TVI, etc.
SWR: 2.0
SWR: 1.5
SWR: 1.0
Frequency
Memorized ATU Tuning
SWR = 3.0
SWR = 2.0
SWR = 1.0
Frequency
SWR (After tuning) Less than 2:1
The tuner settings are stored in the ATU memory.
SWR (After tuning) Greater than 2:1
Tuning data will not be retained in memory. If you return to the same frequency, the tuning process must be
repeated.
SWR (After tuning) Greater than 3:1
The " " icon does not blink, and the tuner settings, if achieved, will not be memorized. Please investi-
gate the high SWR condition and resolve the problem, before attempting further operation using this an-
tenna.
FT-450D O
A
UTOMATIC
A ATU O
BOUT
Feed Point SWR
SWR after ATU Tuning
F
IGURE
©
F
IGURE
About ATU Memories
M
A
NTENNA
PERATION
" icon has appeared. The operator presses and
1
The " " icon appears on the display
when you transmit on this frequency
SWR: 3.0
Retuned Setting
2
T
UNER
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