FTDX1200 Operating Manual Page 65

USING THE AUTOMATIC ANTENNA TUNER
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The Automatic Antenna Tuner (hereinafter referred to as the "ATU") built into each FTDX1200 is designed to ensure a 50-Ohm load for the final amplifier stage of the transmitter. We recommend that the ATU be used whenver you operated on the FTDX1200.

ADVICE:

Becaude the ATU of the FTDX1200 is located inside the station, it only adjusts theimpedence presented to the transceiver at the station end of your coaxial cable feedline. It does not "tune" the SWR at the antenna feed point itself. When designing and building your antenna system, we recommend that every effort be made to ensure a low SWR at the antenna feed point.

The ATU of the FTDX1200 includes 100 memories for tuning data. Eleven of these memories 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 FTDX1200 is designed to match impedences within the range of 16.5 Ohms to 150 Ohms, corresponding to an SWR of 3:1 or less on the 160 through 6 meter amateur bands. Accordingly, simple non-resonant whip antennas, along with random-length wires and the "G5RV" antenna (on most bands) may not be within the impedence matching range of the ATU.

ATU OPERATION
    1. Use the Main Tuning Dial knob to set the radio to the desired operating frequency within the Amateur band.

    2. Press the [TUNE] button momentarily to place the ATU in the transmit line (no adjustment/tuning will occur yet). The "TUNER" icon will appear in the display

QUICK POINT:
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.

    3. Press and hold in the [TUNE] button for one second to begin automatic tuning. The transmitter will be engaged, and the "TUNER" icon will blink while tuning is in progress. When the optimum tuning point has been reached, the radio will return to receive, and the "TUNER" icon will again glow steadily (instead of blinking).

    4. To disconnect the ATU from the transmit line, press the [TUNE] button momentarily. The "TUNER" icon 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 antenna, and will respond to whatever impedance is present at the station end of the coax.

ADVICE:
The ATU circuit is located between the final aplifier and the rear-panel antenna jack; reception is not affected by the ATU.




QUICK POINTS:
As shipped from the factory, only one ATU alignment is saved on each Amateur band. This was memorized during the final alignment and performance verifications stages on the production line.

NOTE:
Please check the operating freqency before beginning the tuning process, to be sure you are not interfering with others who may already be using the frequency.

TERMINOLGY:
Antenna Tuner Memories: The microprocessor of the ATU makes a note of the selected tuning capacitors and inductors, and stores the data for each 10 kHz window for which tuning has occured. This eliminates the need to re-tune every time you return to a frequency on which you have already completed the tuning process.

End of "ATU Operation"

Cont'd Next Page "Using the Automacic Antenna Tuner"
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FTDX1200 Operating Manual Page 65