[Elecraft] KE7X KX3 Book and Configuring: KX3, K3, KPA500, and KAT500

[Phil Hystad]

Fred or others...

I am still a little confused on the diagram in KE7X's KX3 book about hooking up the KX3, K3, KPA500, and KAT500.  My question regard the hookup diagram, figure 9.17, on page 147 on the KE7X KX3 book.

Confusion is about keyline hookup.  The diagram shows that both the K3 and the KX3 must be wired together (via a Y-adapter) in controlling keyline.  Also, that a keyline interrupter is used in the KPAK3AUX cable between the K3 and the KAT500.

Question:  what is a keyline interrupter?  Is this something I have (KX3 cable kit) or is this something I make?  I presume that this is used to block the keyline signal on the AUX cable thus forcing use of the K3 keyline connection directly.  Confirmation on this please.

Question:  if the K3 must be off when I am switched to use the KX3 driving the KPA500/KAT500 then why is this extra keyline hookup needed on the K3?   I mean, if the K3 is off, what function does it supply.  If the K3 is on and the KX3 is off then why not allow the K3 to control keyline via the AUX cable as it is doing right now (in my K3-KPA500-KAT500) configuration.

Thanks for any help you can supply.

73, phil, K7PEH