Using The Automatic Antenna Tuner; Atu Operation - Yaesu FT-2000 Operating Manual

U
SING THE
The Automatic Antenna Tuner (hereinafter referred to as the "ATU") built into each FT-2000D is crafted to ensure a 50-
Ohm load for the final amplifier stage of the transmitter. We recommend that the ATU be used whenever you operate on the
FT-2000D.
A :
The ATU of the FT-2000D, being located inside the station, only adjusts the impedance presented to the transceiver at
the station end of your coaxial cable feedline. It does not "tune" the SWR at the antenna feedpoint itself. When design-
ing and building your antenna system, we recommend that every effort be made to ensure a low SWR at the antenna
feedpoint.
The ATU of the FT-2000D includes 100 memories for tuning data. Eleven of these memories are allocated, one per
Amateur band, so that each band has at least one setting preset for use on that band. The remaining 89 memories are
reserved for the 89 most-recent tuning points, for quick frequency change without the need to retune the ATU.
The ATU in the FT-2000D is designed to match impedances within the range of 16.5 Ohms to 150 Ohms, correspond-
ing to an SWR of 3:1 or less on the HF amateur bands (6 m amateur band: 25 Ohms to 100 Ohms, corresponding to an
SWR of 2:1 or less). Accordingly, simple non-resonant whip antennas, along with random-length wires and the "G5RV"
antenna (on most bands) may not be within the impedance matching range of the ATU.
1. Rotate the [ RF PWR ] knob fully clockwise (to the
right).
2. Use the Main Tuning Dial knob to set the radio to the
desired operating frequency within the Amateur band.
3. Press the [ TUNE ] button momentarily to place the ATU
in the transmit line (no adjustment/tuning will occur
yet). The " " icon will appear in the display.
Q P :
The momentary press of the [ TUNE ] button will turn
the tuner on, and the microprocessor will automatically
select the tuning point closest to the current operating
frequency.
4. Press and hold in the [ TUNE ] button for two seconds
to begin automatic tuning. The transmitter will be en-
gaged, and the " " icon will blink while tuning is
in progress. When the optimum tuning point has been
reached, the radio will return to receive, and the
" " icon will again glow steadily (instead of
blinking).
5. While tuning around the band using the Main Tuning
Dial knob, you will observe that the "
blinks momentarily every 10 kHz. This momentary
blinking indicates that a new tuning window has been
entered. If you want to save tuning data associated with
this 10 kHz window, repeat step 4 (above) for each
such window. On bands like 1.8 MHz where the im-
pedance may change rapidly, the storage of a number
of tuning points is recommended.
6. To disconnect the ATU from the transmit line, press
the [ TUNE ] button momentarily. The "
will turn off, confirming that the ATU has been turned
off. In the "Off" mode, the transceiver will be directly
connected to the coaxial cable connected to your an-
tenna, and will operate based on whatever impedance
is present at the station end of the coax.
Page 66
A
UTOMATIC
ATU O
" icon
" icon
A
NTENNA
PERATION
NOTCH Indicator
A :
The ATU circuit is located between the final amplifier and
the rear-panel antenna jack; reception is not affected by
the ATU.
Q P :
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 veri-
fication stages on the production line.
The momentary flickering of the "
whenever you cross over into a new 10 kHz ATU
memory window.
N :
Please check the operating frequency before beginning the
tuning process, to be sure you are not interfering with oth-
ers who may already be using the frequency.
T :
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.
FT-2000D O
T
UNER
[ DNR ] Knob
[ DNR ] Button
" icon occurs
M