Elecraft KXPA100 Manual - Manual (Page 27)

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Clearing ATU Memories: At the KX3, hold M E N U , and turn the OFS knob to ATU.x
MD . Hold C L R (the OFS knob). MEM CLR will appear on the KX3 LCD while the
ATU memories are being cleared. Do this for each band you want to clear. The tuning
solutions for both antennas are cleared at the same time. Clearing ATU memories is
useful when changing to a new antenna to ensure the ATU stores new tuning solutions
rather than using previous tuning solutions that might not be optimum. Also, you can
clear the memories for selected bands and antennas using the KXPA Utility program
(see page 37).
Operation with a Yaesu FT-817 Using the Optional FT-817 Interface Cable
The following instructions assume that your FT-817 transceiver is connected to the KXPA100 amplifier
using the FT-817 Interface Cable as shown in Figure 4 on page 16.
ALC Adjustment: The KXPA100 Automatic Level Control (ALC) circuit must be adjusted to
provide the correct output power. See Adjusting the KXPA ALC on page 46.
Initial Operation Settings with the FT-817 Interface Cable

On the KXPA100, set the 3 dB ATTEN switch to OUT/AUTO.

Switch the KXPA100 OFF/ ON switch to ON . The ON LED will light.

Connect a 50-ohm dummy load or antenna feed line that presents an SWR of less than 1.5:1 to the
active KXPA100
ANT connector. If you have the optional KXAT100 ATU, the ANT 1 or ANT 2 LED
will light indicating which antenna connector is active and the Man MODE LED will light. If you do not
have the KXAT100 ATU installed use the ANT 1 connector. Hold the KXAT100 AN T switch to change
the selection. Be sure you have a suitable load attached to the active antenna connector.
Amplifier Operation with the FT-817 Interface Cable
Fault Conditions: If the Fault LED on the KXPA100 front panel lights, refer to Faults on page
32 for a description and remedy.
Apply about 2.5 watts of RF drive to the KXPA100:

Transmit Mode: The TX LED on the amplifier front panel will light indicating that it is in transmit
mode. (If the LED does not light, the amplifier remains in receive mode and the RF drive simply passes
through. Check the FT-817 Interface KEYIN1 / TX GND connection in the FT-817 interface cable (see
the schematic diagram on page 45).

Band Switching: The KXPA100 automatically follows band changes at the FT-817. The amplifier also
senses the frequency of the RF from the KX3. If the band data is missing or does not agree with the
frequency sensed for any reason, the amplifier switches according to the frequency sensed.