Elecraft KPA500 Owner's Manual - Manual (Page 11)

11
Connections to the Amplifier
Always turn the amplifier off using the rear panel switch ( in Figure 1) before attaching
or removing cables.
The KPA500 may be used with the Elecraft K3, K2 or any HF/6 meter transmitter that has a PA Key output
meeting the requirements shown under note 4.below. Interconnections the transceiver are shown in Figure 2.
The driving transceiver must provide up to 40 watts of RF drive for full output from the KPA500 and the driving
transceiver output power must be adjustable as described under Transmitting on pg 16.
The optional KPAK3AUX cable provides closer integration with the K3 by sharing band information between
the KPA500 and the transceiver (see Figure 3). The KPAK3AUX cable provides all the operational features
described under Operation, including coordinated band-switching (pg 16). The KPAK3AUX cable includes the
PA Key line. If you need access to this line so that other equipment can control the amplifier, you can install the
Key Line interrupter supplied with your KPAK3AUX cable set and use a separate key line as shown in Figure 4.
You must use the Key Line Interrupter when using a separate key line with the
KPAK3AUX cable set. Otherwise any external equipment inserted into the key line will not
be able to inhibit the amplifier.
You can make cables for use with Yaesu and Icom transceivers that also provide closer integration with the
KPA500. For details of those cables and the KPAK3AUX cable set see AUX Connector Interface on page 26.
NOTE
1. Connect your station ground to the GND thumbscrew . A good station ground is important for safety
and to minimize local radio frequency interference (RFI).
2. Attach the RF INPUT to the output of your driving transceiver or transmitter using a 50 ohm coaxial
cable with a PL-259 male connector on the KPA500 end.
3. Attach the RF OUTPUT to a suitable load with an SWR of less than 1.5:1. A dummy load is strongly
recommended for initial testing.
4. The driving transmitter must ground the PA KEY line circuit during transmit while sinking up to 1 mA.
If the transmitter Key Output is not a contact closure or equivalent, it must be at a level between +4 and
+16 VDC during receive. (Compatible with all known transmitters. No key line buffer required.)