[Elecraft] Elecraft Digest, Vol 128, Issue 32

[Tom Warren]

Jack,

Understood……

After reading your first reply I just went ahead and ran a line to my 12vdc shack bus. It’s just a shame they don’t include a 12v output from the KPA500 to run their companion tuner. 

Your comments are appreciated.

73
Tom
W4TMW



	
> On Dec 18, 2014, at 3:55 PM, elecraft-request at mailman.qth.net wrote:
> 
> Let me rephrase my answer. There is no 12V output form the KPA500. The internal 12V regulator is pretty well loaded, taking most of the capacity of the regulator. The KAT500 needs upwards of 1 amp when the relays are switching, and there is not enough capacity in the KPA?s regulator to handle that and maintain its own circuits (some of which are critical to the KPA?s operation).
> 
> So, no, power to run the KAT500 really cannot be derived from the KPA500. Current K3?s _do_ have capacity on their 12V output, and older ones can be upgraded to handle the current. Or, you can go the route I traveled - build a small relay-switched power distribution box. I use the 12V output form the K3 to power the relay, which simply switches my main 12V shack supply to the peripherals needed when the K3 is on. In my case this includes a W2, KRC2 and KPA500 among other devices.
> 
> Hope this helps.
> 
> 73!
> 
> Jack B, W6FB