KPA500 Remote Control via K3 Macro

Here is how I toggle KPA500 power from the K3 front panel. I have used it for a couple of months on my remote station that is controlled by a prototype K3/0 terminal. It consists of a K3 macro and an additional wire in the AUX cable between the K3 and the KPA500. This simple control is all that is really necessary for remotely operating the amp, as it works along with the AuxBus communications to both enable/disable the amp and also report what the amp is doing. Amplifier status (power ON, OPER mode, power OFF), as well as any faults that occur are reported via AuxBus and show up on the K3's VFO B screen. Even **remotely** on the K3/0!

When you use the KPA500's PWR ON = OPER command to immediately enable OPERate mode when power is turned ON, switching power has basically the same effect as toggling between OPER or STBY mode. The main difference is that instead of being powered ON in standby mode, the amp turns off. Since the MOSFETs have no filaments to wear during power cycling, this does not present a problem. 

If the amp faults, a message appears on the controlling K3's VFO B display. Press the macro key once to turn OFF the amp, then again to turn it back on. (Then turn down the drive power a watt or two so it doesn't happen again!)

Implementation requires two steps.

1) Add a wire to the aux cable connecting DIGOUT1 on the K3 ACC jack (Pin 11) to POWER ON/OFF (Pin 8) on the KPA500 AUX connector.

2) With K3 Utility, program this macro into a K3 function key. (I used PF2, but any should work).
 
MN019;MP001;MN255;MN019;MP000;MN255

This macro turns ON DIGOUT1, waits, then turns OFF DIGOUT1. This is functionally identical to momentarily pressing the KPA500's front panel power button.

Since this is the first K3 macro I have written, and since it worked the first time, I did not bother to optimize it to use the minimum reliable wait times. It is fast enough for my purposes, but you may want to reduce (eliminate?) the waits.

Known Problem:
DIGOUT1 is used by the PR6 6-meter preamplifier to turn it on and off. I have the PR6 and formerly used this function. With the AUX cable modified the way I describe, each time you QSY to 6m, the amp toggles power. Since this is annoying, I chose to disconnect the white power control wire on the PR6 and let it run all the time, instead of only when I am on 6m. Then, I turned OFF DIGOUT1 on 6m (in the K3 menu). Problem addressed, and as far as I'm concerned, solved...

The K3+K3/0 twin remote station works great and the KPA500 was added without requiring yet another serial port to manage and access remotely.


73 de Bob, K6XX