On Tue, 20 Apr 2004 12:41:55 -0500, "Steve Nosko"
wrote:

Cap the bottom to fix
this. Leave a little air/vacuum/(a.k.a. mercury vapor) on top if you must
use a glass tube.

Hi Steve,

It doesn't work that way. The mercury will create its own void -
thing called gravity and the pressure of the atmosphere around us are
in competition (even if the tube is sealed). Fill it to absolute
capacity (no reservoir) and you will either pop the tube (thing called
thermal expansion) or draw a vacuum.

Pressure, gravity, temperature - all things mercury is sensitive to.
It would be easier to herd cats.

73's
Richard Clark, KB7QHC

On Tue, 20 Apr 2004 13:05:32 -0700, Jim Kelley
wrote:

In fact, the tuning length of the column of mercury could
be controlled simply by tilting the tube of mercury at an
angle away from vertical in the direction of horizontal.
--
73, Cecil http://www.qsl.net/w5dxp

How much does the length change when you tilt it at 45 degrees?

Hi Jim,

Look at it from either end and it is only a millimeter long. More new
physics of antennas (optics based too).

73's
Richard Clark, KB7QHC

Jim Kelley wrote:

Cecil Moore wrote:
"Tilt" is very good advice for a variable mercury column.
In fact, the tuning length of the column of mercury could
be controlled simply by tilting the tube of mercury at an
angle away from vertical in the direction of horizontal.

How much does the length change when you tilt it at 45 degrees?

By the factor of the square root of two.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore wrote:

Jim Kelley wrote:

Cecil Moore wrote:
"Tilt" is very good advice for a variable mercury column.
In fact, the tuning length of the column of mercury could
be controlled simply by tilting the tube of mercury at an
angle away from vertical in the direction of horizontal.

How much does the length change when you tilt it at 45 degrees?

By the factor of the square root of two.

Sounds kinda like one of those mythical cable stretchers. :-)

ac6xg

Jim Kelley wrote:

Cecil Moore wrote:

Jim Kelley wrote:
How much does the length change when you tilt it at 45 degrees?

By the factor of the square root of two.

Sounds kinda like one of those mythical cable stretchers. :-)

By Golly, I have been looking for a cable stretcher. A tilted
mercury column will perform that function. Question is, what
do I mix with the mercury column to make it more conductive?
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore wrote:

Jim Kelley wrote:

Cecil Moore wrote:

Jim Kelley wrote:
How much does the length change when you tilt it at 45 degrees?

By the factor of the square root of two.

Sounds kinda like one of those mythical cable stretchers. :-)

By Golly, I have been looking for a cable stretcher. A tilted
mercury column will perform that function.

How so?

Question is, what
do I mix with the mercury column to make it more conductive?

Maybe it'll superconduct if it gets cold enough. :-)

73, ac6xg

Jim Kelley wrote:
Cecil Moore wrote:
By Golly, I have been looking for a cable stretcher. A tilted
mercury column will perform that function.

How so?

The gravity vector remains constant while the tilted mercury
vector varies with the angle of the tilt. Let's say theta
is the angle of the tilt, i.e. the angle between the mercury
column and the ground plane. At an angle of 45 degrees, the
mercury column length will be 1.414 times the length at 90 degrees,
At 10 degrees, the mercury column length will be 5.76 times the
length at 90 degrees. That sounds like something worth patenting.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil, are you thinking of an open ended tube of Hg with a variable
supply of Hg?? My days with Hg manometers comes to mind.

If it's a closed tube then the length does not change with angle.

So, you can have your variable length antenna and not have it too!!

Deacon Dave

Cecil Moore wrote:

Jim Kelley wrote:

Cecil Moore wrote:

"Tilt" is very good advice for a variable mercury column.
In fact, the tuning length of the column of mercury could
be controlled simply by tilting the tube of mercury at an
angle away from vertical in the direction of horizontal.


How much does the length change when you tilt it at 45 degrees?


By the factor of the square root of two.
--
73, Cecil http://www.qsl.net/w5dxp



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David.Shrader wrote:
If it's a closed tube then the length does not change with angle.

I may be wrong, cuz I'm not very mechanical, but it seems to me
that a column of mercury in a tube with a vacuum at the top
and a reservoir of mercury at the bottom would change height
of column depending on the angle of the column's deviation from
vertical. It seems to me that when the column is horizontal,
there would be no vacuum at all in the tube.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore wrote:
Forget about the feasibility of this question for the moment.
Could a column of mercury inside a tube of glass be used as an
antenna?
--
73, Cecil, W5DXP



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It's probably been mentioned before, but there is a group that has
covered liquid antennas in great detail. See -

http://groups.yahoo.com/group/Live-Wire/

Most of the liquid antennas are salt water based, but the idea is the same.

Tom
K0TAR, ex WA2PHW

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