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"Richard Fry" and "Richard Clark" argue about:
...which characteristic of sea water is responsible
for its lower groundwave path loss...
...because sea water is a good reflector.
...because of its good conductivity.

Is sea water a good reflector because it has good conductivity ?

;-)




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On Sat, 4 Sep 2004 06:42:45 -0500, "Richard Fry"
wrote:
You quote only a part of my post

Hi OM,

I don't quote the full message because it is already available, and
further, it is bad manners to do so unless something new and relevant
has been offered. None so appears.

73's
Richard Clark, KB7QHC

On Sat, 4 Sep 2004 09:39:56 -0300, "Just a suggestion..."
wrote:

Is sea water a good reflector because it has good conductivity ?

If you think it has good conductivity, do you wire your house with it?
Do you have a radial field using #38 wire in a one meter grid? Both
laughable propositions here, but those tears of mirth turn to the
dewey eyed mist of religious belief when Salt Water "conductivity" is
mentioned.

Sand is the least lossy ground beneath your feet, but how well does it
contribute to DX? Add some water and the loss skyrockets - and this
is called the boon of conductivity!

No, it is called the boon of reflectivity. The Z changed and power
CANNOT penetrate the interface. If you cannot get power into it,
there is nothing to conduct (and it is the molecular polarization and
relaxation moment that causes this, not conductivity).

The legends of mature spinsters are many with respect to the qualities
of ground - they even inspire useless software as crutches. I have
seen NO ONE here who can recommend it (much less admit they don't even
have a clue on what values would be appropriate for their own locale).
Hence most discussion is either faith-driven, speculation, or simple
hucksterism.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote
Richard Fry wrote:
You quote only a part of my post

it is bad manners to do so unless something new
and relevant has been offered. None so appears.
_________

I doubt that the majority of readers will agree with you about the relevancy
of my posts on this thread to yours. You have simply chosen not to address
them.

But in any case...Pax vobiscum.

RF

Sand is the least lossy ground beneath your feet, but how well does it
contribute to DX? Add some water and the loss skyrockets - and this
is called the boon of conductivity!

No, it is called the boon of reflectivity. The Z changed and power
CANNOT penetrate the interface. If you cannot get power into it,
there is nothing to conduct (and it is the molecular polarization and
relaxation moment that causes this, not conductivity).


It's been many years since my EM theory days in school, but I seem to
remember being taught that the way surfaces reflect EM waves is by being
excited by the impinging wave and then re-radiating due to the current flow
caused by the arriving wave. This would require the surface to be a good
conductor to be a good reflector.

"Richard Clark" wrote in message
...
On Sat, 4 Sep 2004 06:42:45 -0500, "Richard Fry"
wrote:
You quote only a part of my post

I don't quote the full message because it is already available, and
further, it is bad manners to do so unless something new and relevant
has been offered.

(Three hours later)

"Richard Clark" wrote in message
...
On Sat, 4 Sep 2004 09:39:56 -0300, "Just a suggestion..."
wrote:

Is sea water a good reflector because it has good conductivity ?
(clippage)
The legends of mature spinsters are many with respect to the qualities
of ground - they even inspire useless software as crutches. I have
seen NO ONE here who can recommend it (much less admit they don't even
have a clue on what values would be appropriate for their own locale).
Hence most discussion is either faith-driven, speculation, or simple
hucksterism.
_________________

Good Sir,

A bit of a disconnect appears to occur in the above two clips between your
stated desire to avoid bad manners, and the consistency with which you do
it. Most people are more willing to entertain another's point of view if
such is given without hostility and intimidation.

With all due respect,

RF

On Sat, 04 Sep 2004 19:55:48 GMT, "GW"
wrote:

This would require the surface to be a good
conductor to be a good reflector.

Hi OM,

Replace any low Ohm plane with a hi Ohm plane. No conduction issues
(or even vastly worse than salt water) there at all, same reflection -
n'est pas?

For those who've studied freshman Physics, this is called Snell's Law.

73's
Richard Clark, KB7QHC

You all seem to have forgotten the very high permittivity of water. Does
this not affect reflectivity? A question for Cecil?

On Sat, 04 Sep 2004 17:04:49 GMT, Richard Clark wrote:

(and it is the molecular polarization and
relaxation moment that causes this, not conductivity)
On Sat, 4 Sep 2004 22:56:12 +0000 (UTC), "Reg Edwards"
wrote:

You all seem to have forgotten the very high permittivity of water. Does
this not affect reflectivity? A question for Cecil?


Ah Punchinello!

Clowning as ever, I see. A seque from the world's worst conductor to
the world's worst dielectric? This is the price of superlatives in
place of engineering specifics. Whatsamatta, did you defrock your
saint Kelvin?

What is the loss tangent of the mud in your garden Reggie? ;-)

Well, anticipating your typical loss for a response, and for others, a
nice round value of 1 is easily within rough accuracy. Corrections
(not speculations) are encouraged. Be specific.

73's
Richard Clark, KB7QHC

Maximum ground loss during wave reflection, between low resistance sea water
and very high soil resistivities, could very well be when soil impedance is
of the order of 377 ohms. Or is related to that number.

This is because, on the average of incidence angles, soil is more likely to
absorb than reflect wave energy received from free-space. There's a better
impedance match with free space at 377 ohms. The reflection coefficient is
smaller.

Soil permittivity and frequency will also have an effect on the ballpark in
which maximum absorption and hence maximum transmission loss lies.
---
Reg, G4FGQ