On Wed, 19 Jul 2006 23:14:33 +0100, "David" nospam@nospam wrote:

I agree that in the coax side, there is no real 0V because the current has a
standing wave.

Hi Dave,

This doesn't really make much sense. Even discounting that and trying
to extrapolate your response, it isn't even 0V then and not true for
SWR in general.

But the transceiver has a DC power supply (normally 12V) that
is controlled or modulated.

A modulated power supply? Even if you mean regulated, it bears no
resemblence to the topic.

One side of the power supply is regarded as 0V
and connected to 0V rail of circuits. The modulated side is the RF live that
is connected to the centre contact of transceiver output connector.

It will, then, come as a surprise to you that the output of the
transmitter comes from an AC coupled link. You may choose either wire
in that link to go to any part of a ground system, or conversely, to
what you consider to be the radiator. It makes no difference because
there is no
Ground
Hot
Cold
Dead
Live
or any other distinction until you plant that wire. You can paint
that wire turquoise in the belief that it is safe, and grab it at a
later time to fry you.

In theory, while transceiver is transmitting, if I touched the outer of the
output connector, I would not expect to get a shock or RF burn.

Expectations here are a belief system, not a proof. I suggest you
stay away from situations that encourage such lethal presumptions.

If I touched
the centre contact of output connector, then I would expect to get a shock
or RF burn. Admittedly, I could touch the outer and find that I am close
enough to the centre contact for RF to capacitively couple into me. In real
life, I would never touch the output connector while the rig is
transmitting.

Does RF live and ground not exist on the output connector of the
transceiver?

There are no absolutes as you might expect. Plenty of correspondents
here complain daily of problems stemming from what you might deny. If
you worked your rig on 10M or 20M from the second story window, you
are so far from ground, electrically, that its apparent proximity is
only an illusion.

73's
Richard Clark, KB7QHC