Has anyone built a SunSDR2 DX Ext Ctrl interface cable for an Elecraft KPA500 amplifier?

Initially, I was going to build a cable just for PTT with a CPC1035N solid-state relay and diode and capacitor protection. However, it looks like it should be relatively easy to build a more robust cable with automatic band-switching and possibly ALC in addition to PTT.

Here’s what I’ve come up with so far. Based on the specs for both pieces of equipment, it doesn’t look like additional relay or diode protection will be required.

Will a simple cable with these 6 connections work?

Thanks and 73,
Sheldon, VE1GPY/VE1SL

Sheldon,

A simple cable certainly works for me. I can't find my notes on this unfortunately, but it did take me some time to get my head around the ext ctrl settings and mine are similar, but not identical to yours. I've attached them for your interest. I'm using a SunSDR2 pro which might explain the difference.

73 Stephen G4SJP

Thank you, Stephen!!
That’s encouraging and seems to confirm that additional relay and diode protection will not be required.

It looks like your Ext Ctrl is programmed the same as mine. The big difference is in the choice of programable keys (pins) for the BCD values. Yours uses (X6,X5,X4,X3) while mine uses (X4,X5,X6,X7). It also looks like you may have X7 explicitly programmed to generate PTT instead of the default X8.

73,
Sheldon, VE1GPY/VE1SL

Sheldon
Try looking in the USER Manual Addendum UMA, its all in there including for use with the KPA500 & the KPA1500.
The UMA is in the MB1 section, under Software.
73
Ray G3XLG