[Kenwood] Undocumented feature in 450/690?

[Ken, WA2LBI]

John,

Have you checked the negative power supply connection?  I'm concerned 
that your rig may be receving the negative 12VDC/ground through the 
shield of the antenna coax.

Ken, WA2LBI

Quoting "John  Geiger (NE0P)" <ne0p at lcisp.com>:

> My Kenwood TS690 turns off when I disconnect the antenna, or when 
> there is no antenna connected I cannot turn it on?  Is this normal 
> behavior for this rig?
>
> 73s John NE0P