Elecraft KXPA100 Manual - Manual (Page 24)

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Operation with a KX3 Transceiver using the KX3 to KXPA100 Adapter Cable
This provides the most efficient integration of the KX3 transceiver, the KXPA100 amplifier and the KXAT100
Antenna Tuning Unit (ATU). Normally you will not need to touch the KXPA100 amplifier. All operation takes
place at the KX3 front panel similar to operating the KX3 by itself.

Connections: Your KX3 must be connected to the KXPA100 amplifier with the KX3 to KXPA100
Adapter Cable as shown in Figure 3 on page 14.

Firmware: Your KX3 must be equipped with firmware level 1.74 or later. To check the firmware level,
turn your KX3 on and hold
M E N U . Turn the OFS knob to FW REVS and read the firmware level on the
upper part of the K3 LCD. If needed, update your firmware as described in your KX3 Owner’s Manual.

Fault Conditions: If at any time PA FLT is displayed on the KX3 LCD or the Fault LED on the
KXPA100 front panel lights, refer to Faults on page 32 for descriptions and remedies.
Initial Settings Using the KX3 to KXPA100 Cable
1. Apply dc power to the KXPA100 amplifier and KX3.
2. Leave the amplifier ON/OFF switch in the OFF position. Power to the amplifier will be controlled at the
KX3.
3. Set the amplifier rear-panel 3 dB ATTEN switch to OUT/AUTO.
4. At the KX3, hold M E N U and turn the OFS knob to TUN PWR.
5. Turn the VFO A knob to nor .
6. Turn the OFS knob to PA MODE .
7. Turn the VFO A knob to On . The KXPA100 amplifier ON LED will light. If the KXPA100 is equipped with
the optional KXAT100 ATU, the ANT 1 or ANT 2 and MODE Man LEDs will also light.
8. Tap M E N U to exit the KX3 menu.
9. Connect a 50-ohm dummy load or antenna to the KXPA100 active ANT connector indicated by the lighted
ANT 1 or ANT 2 LED.
Amplifier Operation Using the KX3 to KXPA100 Cable
Operation is almost identical to operating the KX3 without the amplifier. The internal KXAT3 ATU, if installed,
is automatically bypassed when you switched the KX3 menu to
PA MODE On step 4 above. The amplifier
presents a low SWR to the KX3 on all bands.
 Antenna Selection: If the KXPA100 is equipped with the optional ATU, hold the KX3
AN T switch to
toggle between the ANT 1 and ANT 2 antenna connectors on the KXPA100. The selected antenna is
displayed on the KX3 LCD when the selection is changed, ANT.x 1 or ANT.x 2 , and on the front panel
LEDs on the KXPA100. Be sure you have an antenna or dummy load connected to the active
antenna port before transmitting.