[Elecraft] Fw: K3/KAT500/KPA500 integration question

[Andy Durbin]

Jack,

That for taking the time for your detailed reply.   It seems there is some risk that a fully integrated K3, KAT500, and KPA500 could experience a power spike for the scenario I proposed.

Up to this morning I had been opening the KAT500 key line anytime my TS-590 was set to 40 W or more regardless of KPA500 mode.  This is the pro-active overdrive protection I had previously told you about.  With that implementation I saw a 600 W power spike when I selected OPER during an FT8 transmission with 37 W set for STBY but 8 W set as OPER band power.   My setting of OPER band power will be much slower than the K3 response to the Aux bus signal.

This morning I changed my controller code so KAT500 key line is always open when KPA500 is STBY.  When I see KPA500 change to OPER I wait a second to allow OPER band power to be set and then enable the KAT500 key line.   This greatly reduces the risk of a power spike at the STBY to OPER transition.  Here is the diagnostic output for the transition 37 W STBY to 8 W OPER:

 2:39:22.997  New KPA_mode  - ^OS1;
 2:39:22.998  STBY_OPER_time set
 2:39:23.145  Sending PC008; to Kenwood
 2:39:23.388  New PC - PC008;
 2:39:23.999  power_prot_limit=40
 2:39:24.000  Power protection cleared
 2:39:24.001  KEN power verified
 2:39:24.003  Sending AMPI0; to KAT500
 2:39:24.062  New AMPI  - AMPI0;

My power management code is not all that complex but it has taken a while to understand and accommodate the various "corner cases".     Your willingness to share your insights has been helpful.

73,
Andy, k3wyc