Cecil Moore wrote:

Tom Donaly wrote:

For someone like me, Cecil can be (but usually isn't) a very useful
crackpot. I can be pretty sure he's wrong, but the process of educating
myself into turning that hunch into a dead certainty that I can prove
to everyone (except him) can be enlightening.


Now's your chance to enlighten us, Tom. Please explain again
how the standing wave current magnitude on a 1/2WL thin-wire
dipole doesn't depend upon how many degrees it is away from
the feed point, i.e. doesn't contain any phase information.

While you are at it, please explain exactly how Kraus is mistaken
about this antenna when he plots the standing wave current as
I = cos(X) where X is the number of degrees away from the
feedpoint and feedpoint current equals 1 amp at 0 degrees.

I didn't say that the value of the standing wave current on a
1/2 wavelength dipole doesn't vary with length. I did say that
just measuring the value at some point doesn't give you all the
information you need to calculate the phase. Of course, you already
know the phase, because you defined the antenna as 1/2
wavelength, so finding any kl is trivial. Secondly, even if you're
right about the current in your antenna being a sine function, in order
to use that information, you have to measure the current input at the
current maximum - which you've already defined to be the center of the
antenna - in order to compare it with the current at the point of
interest in order to get your result. In short, you still have to
know the current at two points in order to get an answer. The
information isn't contained in just one measurement. So let me turn it
around and ask you to tell me again why you think you can get some
"phase" information from measuring a single point on an antenna
without knowing anything else about it.

I haven't read Kraus, but I expect he was talking about an idealized,
infinitely thin antenna. Add thickness to the wire, and a feedpoint gap,
and you may come up with something slightly more complicated.
73,
Tom Donaly, KA6RUH