[Elecraft] K3 Key Out Jack Not Working

[Don Wilhelm]

Pete,

Check the Keyout jack with your ohmmeter.  One lead to the center 
conductor and the other to the shell.
During receive, it should read infinite resistance, and when you go to 
transmit, the resistance should go to near zero.

Do you have anything else connected to the KEYOUT jack (an amplifier 
perhaps)?  If so, you will have to use isolating diodes for the amp and 
your relay for the antenna.

73,
Don W3FPR

On 12/27/2019 6:12 PM, N4ZR wrote:
> I'm trying to set things up so that I can disconnect my 160M transmit 
> antenna whenever I'm receiving, to prevent noise coupling into my RX 
> antenna.  My thought is to use the Key Out jack on the K3 to control DC 
> to a relay at the base of the antenna,  floating the base of the 
> inverted L unless PTT is asserted.  The lashup is complete, and works 
> when I short the phono plug manually, but not when I plug it into the 
> KEY OUT jack and energize PTT.
> 
> I'm hoping it's just a menu issue, but my manual doesn't show any menu 
> options affecting the Key Out Jack.  I have a KPA-1500, and Low Power 
> Key Out via the ACConnector works fine for controlling the amplifier, so 
> I assume the basic functionality is OK.  Any advice?  I'd really love to 
> get it going for the Stew tomorrow!