About Atu Operation - Yaesu FTDX9000D - DATA MANAGEMENT Operation Manual

As shipped from the factory, only one ATU alignment point is saved on each Amateur band. This was memo-
rized during the final alignment and performance verification stages on the production line.
The momentary flickering of the [ TUNE ] switch's LED occurs whenever you cross over into a new 10 kHz
ATU memory window.
Although transmitter power is decreased to 100 Watts (maximum) during tuning, by all means please check the
operating frequency before beginning the tuning process, to be sure you are not interfering with others who may
already be using the frequency.
Antenna Tuner Memories
The microprocessor of the ATU makes a note of the positions of the tuning capacitors and the selected inductors,
and stores the data for each 10 kHz window in which tuning has occurred. This eliminates the need to re-tune every
time you return to a frequency on which you already have completed the tuning process.
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
Feed Point SWR
SWR = 1.5
SWR = 1.0
Frequency
SWR after ATU Tuning
Figure 1
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 indi-
cate 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
U
SING THE
ATU O
PERATION
Q Q Q Q Q
UICK UICK
UICK UICK UICK
N N N N N
O O O O O TE
T T T T T
ERMINOL ERMINOL ERMINOLOGY
ERMINOL ERMINOL
A ATU O
BOUT
About ATU Memories
M
ANUAL
A
UTOMATIC
P P P P P
OINT OINT
OINT OINT OINT
TE TE TE TE
OGY OGY OGY
OGY
PERATION
Memorized ATU Setting
SWR = 3.0
SWR = 2.0
SWR = 1.0
Frequency ①
Figure 2
A T
NTENNA UNER
Retuned Setting
②
Page 89