Elecraft KAT500 Owners Manual User Manual
Page 10
7
Key Line Cables
The Key Line (sometimes called a PTT line) controls the amplifier, enabling it for normal
transmission and inhibiting it when necessary to protect the amplifier other equipment. The
key line consists of a two conductor (center wire and shield) cable and connects to the
Elecraft equipment using RCA-type male connectors.
The K3 transceiver grounds the Key line to enable the KPA500 amplifier. Opening this line
anywhere between the K3 and the KPA500 will inhibit the amplifier. If you have an external
device that must control the key line, such as a SteppIR controller, you may insert it series
with the key line in either place indicated with the
using connectors that match those on
the external device.
If you need additional cables, you can make your own or order additional cables from
Elecraft (part number E100416). The Elecraft cables use RG59 coaxial cable for optimum
shielding against incidental RF pickup.
IMPORTANT
When using a separate Key Line cable, you must:
1. Interrupt the key line in the E850463 Aux cable as described
in note
below.
2. Use a separate key line cable between the transceiver and
between the KAT500 and between the KAT500 and the
amplifier. You cannot use an E850463 Aux cable in one
location and a separate key line cable in the other.
Key Line Interrupter
The E850463 Aux cable includes the key line that inhibits the amplifier when needed to
protect other equipment. This circuit must be broken when using an external key line cable or
the key line in the E850463 Aux cable will bypass the external cable and the external
equipment will not be able o inhibit the amplifier. If you purchased the Elecraft Aux cable as
part of the KPAK3AUX cable set, you received with it a small device called the Key Line
Interrupter that opens the key line. The key line is cut inside the Inhibiter so you do not need
to modify your E850463 Aux cable in any way. If you only purchased the E850463 Aux
cables you can order a key line interrupter separately. Order E850462 from
[email protected]
If using a homemade cable, you can cut the circuit at pin 10 (see Table 1. E850463 Aux Cable
Wiring. on page 4)