Cecil Moore wrote:
Jim Lux wrote:
Another problem.. there's no net charge on your coffee.. so no
radiated field when you move it back and forth.

How many free electrons in coffee? How about salt water?

pH = -log hydrogen ion concentration

the pH is about 7, so hydrogen ion concentration is 1E-7. It's
neutral, so there's an equal number of negative ions. How many of them
are free electrons is another question.


But the important thing is that there's an equal number of positive and
negative charges floating around there, so there's zero net charge. An
possible radiated field from a negatively charged electron will be
exactly matched by the opposite field from a positively charged
something else.

On Mon, 06 Jul 2009 08:22:19 -0700, Jim Lux wrote:

Cecil Moore wrote:
Jim Lux wrote:
Another problem.. there's no net charge on your coffee.. so no
radiated field when you move it back and forth.

How many free electrons in coffee? How about salt water?

pH = -log hydrogen ion concentration

the pH is about 7, so hydrogen ion concentration is 1E-7. It's
neutral, so there's an equal number of negative ions. How many of them
are free electrons is another question.


But the important thing is that there's an equal number of positive and
negative charges floating around there, so there's zero net charge. An
possible radiated field from a negatively charged electron will be
exactly matched by the opposite field from a positively charged
something else.

The pH of water in contact with the atmosphere tends to be about 6.5, due
to CO2 dissolving in the water and forming carbonic acid. Other commonly-
occurring ions that "match" the H+ are sulfate and nitrate. Of course in
salt water, most of the ions are sodium (Na+) and chloride (Cl-). Not
many free electrons. The motion of any ions could create electromagnetic
radiation, but as you note, the net charge is zero, so no radiation,
regardless how the cup is accelerated or what speed it travels at ;-)

--
Rich

Jim Lux wrote:
But the important thing is that there's an equal number of positive and
negative charges floating around there, so there's zero net charge. An
possible radiated field from a negatively charged electron will be
exactly matched by the opposite field from a positively charged
something else.

Does that mean a column of salt water could not be
used as an antenna?
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

On Mon, 06 Jul 2009 13:19:09 -0500, Cecil Moore wrote:

Jim Lux wrote:
But the important thing is that there's an equal number of positive and
negative charges floating around there, so there's zero net charge. An
possible radiated field from a negatively charged electron will be
exactly matched by the opposite field from a positively charged
something else.

Does that mean a column of salt water could not be used as an antenna?

It just means that moving the water back and forth won't cause
radiation. Waves on the surface of the ocean don't make radio signals.
(C'mon, Cecil. You knew the answer to your question, didn't you? ;-) )

The column of water will conduct a current, which will radiate, but I
think I'd rather use copper or aluminum :-)

--
Rich

Rich Griffiths wrote:
(C'mon, Cecil. You knew the answer to your question, didn't you? ;-) )

Actually, I had never thought about it. I assumed that any
conductor would radiate.

I've been working on a particle beam that ionizes 33 feet
of air for use as an efficient mobile antenna on 40m. Have
I been wasting my time?
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

"Cecil Moore" wrote

I've been working on a particle beam that ionizes 33 feet
of air for use as an efficient mobile antenna on 40m. Have
I been wasting my time?

Unless you can stuff that antenna into a container the size
of two shoe-boxes, and achieve a 9 point something dBi
gain on 160M at the same time, yeah, you're wasting time.
Art's already beat you to it. And Art's antenna doesn't
care one never-mind about the phase information in the
standing wave current ;) good luck in the contest.

Mike W5CHR
Memphis

On Mon, 06 Jul 2009 15:39:34 -0500, Cecil Moore wrote:

snip

I've been working on a particle beam that ionizes 33 feet of air for use
as an efficient mobile antenna on 40m. Have I been wasting my time?

Wasting your time? Heavens no! That would be WAY cool!

Even if it didn't work as an antenna, think how exciting it would be for
birds, people watching the highway from overpasses, ....

--
Rich

"Cecil Moore" wrote in message
...
Jim Lux wrote:
But the important thing is that there's an equal number of positive and
negative charges floating around there, so there's zero net charge. An
possible radiated field from a negatively charged electron will be
exactly matched by the opposite field from a positively charged
something else.

Does that mean a column of salt water could not be
used as an antenna?

If a VEE antenna were formed of two hoses, these "elements" could be
partially filled with brine and tuned by draining or adding brine. The
metal fittings on the lower ends of the VEE elements would be the feedpoint.

Reductio ad absurdum

LXXIII,
Sal

Sal M. Onella wrote:
"Cecil Moore" wrote in message
...
Jim Lux wrote:
But the important thing is that there's an equal number of positive and
negative charges floating around there, so there's zero net charge. An
possible radiated field from a negatively charged electron will be
exactly matched by the opposite field from a positively charged
something else.
Does that mean a column of salt water could not be
used as an antenna?

If a VEE antenna were formed of two hoses, these "elements" could be
partially filled with brine and tuned by draining or adding brine. The
metal fittings on the lower ends of the VEE elements would be the feedpoint.


been done, been patented too, I think.

(conductive liquid as a changeable antenna element)

"Jim Lux" wrote in message
...

snip

If a VEE antenna were formed of two hoses, these "elements" could be
partially filled with brine and tuned by draining or adding brine. The
metal fittings on the lower ends of the VEE elements would be the
feedpoint.


been done, been patented too, I think.

(conductive liquid as a changeable antenna element)

Aw, phooey! I never get to invent ANYTHING!