[Elecraft] KX3 s/n 1965 on the air - and a power-up question

[Bob Cunnings]

Is the negative lead from your power supply to the KX3 open, maybe at
the DC input connector? If so, return current could be flowing through
the coax shield, antenna system ground etc. to find its way back to
the Ten-Tec supply through its chassis to V- connection. Disconnecting
the coax would interrupt power to the rig in such a case.

Might be worth checking.

Bob NW8L

>I'm very excited to get my new KX3 on the air, and during my initial
>exploration of the rig, I discovered something unexpected. It appears
>that the rig will not power on if there is no antenna attached. I
>noticed this first when I disconnected the coax to change the antenna
>setup while the rig was on and in receive mode  - the rig immediately
>shut down. Then with the antenna disconnected I tried to power up - no
>response. After reconnecting the antenna, everything behaved normally.
>
>I did not find any mention of this in the manual. I don't have an ATU
>installed, perhaps that might have an effect.
>
>I am running from an external 20A power supply (a venerable TenTec
>252M), and the load is RG 8X connected to an LDG Z-11 autotuner,
>feeding an outdoor dipole.
>
>If this is normal behavior, does it have implications for doing
>firmware updates? Must the rig have some kind of load attached in
>order to power on to connect to the computer?
>
>In all other respects everything is working fine and I am very pleased
>with the rig. My first CW contact was Bulgaria on 10w from the east
>coast!
>
>73
>Mike N2HTT