My EM guys, Physics types, [from my working days] indicated that the
three dielectric interfaces, adhesive to glass to adhesive, all with
different dielectric coefficients create reflections at the boundaries.

There are four. You couldn't really have an odd number..

Metal-adhesive, adhesive-glass, glass-adhesive, adhesive-metal.

Then there's the tuner box and all that on the feedline to consider.
Not surprising that there's some significant loss in the process.

Dick,

I think the reason that is a safe place is that the auto manufacturers
know that drivers like to mount radar detectors there, and that requires
an RF-transparent section of glass.

73,
Bob AD3K

Dick, AA5VU wrote:
Jim,

Think about the front windshield behind the rear view mirror. That is
where I ran one on a Z-28 and Corvette and it worked great.

Dick - AA5VU

In article ,
"JLB" wrote:


I have a 2000 model year Ford Taurus wagon, and am thinking about mounting a
through-glass antenna on one of the back side windows. Yes, I know---a roof
mount would work better, but I would have to get a hole punch and a divorce
lawyer to do it ;-)

Does anyone have any practical experience with this set up? Does the window
tinting cause any problems on 146 MHz or 440 MHz? There is a completely
dark (opaque) band around the edge of the window. Should this be avoided?

I have seen Taurus wagons with cell phone antennas on the back side windows,
and was wondering how it worked on the ham bands.

Jim
N8EE

--
Robert L. Spooner
Registered Professional Engineer
Associate Research Engineer
Intelligent Control Systems Department

Applied Research Laboratory Phone: (814) 863-4120
The Pennsylvania State University FAX: (814) 863-7841
P. O. Box 30
State College, PA 16804-0030

Wasn't it James Thurber who said, "When someone says 'theoretically,' he
means 'not actually.'"?

73
Bob AD3K

Richard Clark wrote:

On Mon, 05 Apr 2004 23:54:51 GMT, Dave Shrader
wrote:

Theoretically, the loss is about 0.5 to 1.0 dB for clear glass.


Hi Dave,

What's the theory?

73's
Richard Clark, KB7QHC

--
Robert L. Spooner
Registered Professional Engineer
Associate Research Engineer
Intelligent Control Systems Department

Applied Research Laboratory Phone: (814) 863-4120
The Pennsylvania State University FAX: (814) 863-7841
P. O. Box 30
State College, PA 16804-0030

Robert Spooner wrote:
Wasn't it James Thurber who said, "When someone says 'theoretically,' he
means 'not actually.'"?

73
Bob AD3K

When I use 'theory' or 'theoretically', I'm using it in the engineering
context of Physics and Mathematics. Meaning the mathematical solution
of the LAWs of Physics are applicable.

There are other understandings of theory: such as the district
attorney's theory behind a crime; or, in science terms the next step
beyond 'hypothesis'; or, the step below 'law of nature'.

The theory is understanding 'WHY' things are actually, to quote your
word above. Knowledge, in engineering and science, is incomplete without
the THEORY of operation or Physics.

So, I reject your hypothesis regarding Thurber's statement. It is
inconsistent with science/engineering/physics.

Bob, AD3K, made a good point that I overlooked. I had very good success
with the thru-the-glass behind the rear view mirror. It even cleared the
garage door.

I drive a C5 Corvette now and could not figure out where to mount the
dual-bander so it is mounted on a bean bag lap top desk and ride in the
passenger seat or on the hump when someone is onboard. The antenna is a
small dual-band mag mount on a thin steel plate in the hatch area. It
works!

dick aa5vu

In article ,
Robert Spooner wrote:

Dick,

I think the reason that is a safe place is that the auto manufacturers
know that drivers like to mount radar detectors there, and that requires
an RF-transparent section of glass.

73,
Bob AD3K

Dick, AA5VU wrote:
Jim,

Think about the front windshield behind the rear view mirror. That is
where I ran one on a Z-28 and Corvette and it worked great.

Dick - AA5VU

In article ,
"JLB" wrote:


I have a 2000 model year Ford Taurus wagon, and am thinking about mounting a
through-glass antenna on one of the back side windows. Yes, I know---a roof
mount would work better, but I would have to get a hole punch and a divorce
lawyer to do it ;-)

Does anyone have any practical experience with this set up? Does the window
tinting cause any problems on 146 MHz or 440 MHz? There is a completely
dark (opaque) band around the edge of the window. Should this be avoided?

I have seen Taurus wagons with cell phone antennas on the back side windows,
and was wondering how it worked on the ham bands.

Jim
N8EE

On Tue, 06 Apr 2004 11:48:53 GMT, Dave Shrader
wrote:

Richard Clark wrote:

On Mon, 05 Apr 2004 23:54:51 GMT, Dave Shrader
wrote:

Theoretically, the loss is about 0.5 to 1.0 dB for clear glass.


Hi Dave,

What's the theory?

73's
Richard Clark, KB7QHC

My EM guys, Physics types, [from my working days] indicated that the
three dielectric interfaces, adhesive to glass to adhesive, all with
different dielectric coefficients create reflections at the boundaries.

Hi Dave,

Poor theory. Reflection is not loss. There are reflections galore on
a radiator that supports the Standing Wave and yet with a large enough
metal surface it is nearly 100% radiative.

As for this boundaries explanation, those "Physics types" clearly did
not have any working knowledge (experience) - about as useful as
Cecil's poorly offered Light analogies suffering from the same lack.
I further note that none of this indicts clear glass (which may have
been a semantic issue) to the tune of nearly 1dB.

73's
Richard Clark, KB7QHC

On Tue, 06 Apr 2004 15:02:45 GMT, Dave Shrader
wrote:

Robert Spooner wrote:
Wasn't it James Thurber who said, "When someone says 'theoretically,' he
means 'not actually.'"?

73
Bob AD3K

When I use 'theory' or 'theoretically', I'm using it in the engineering
context of Physics and Mathematics. Meaning the mathematical solution
of the LAWs of Physics are applicable.

Hi Dave,

This is a catch-all application of "theory." The solutions are
always applicable and the casual employment of the phrase "in theory"
is thus rendered gratuitous (or rhetorical chaff) - hence the
attachment of Thurber's observation that is a sardonic reference to
the lack of any actuality. You have confirmed that his artistic prose
has as much validity as Physics.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
Cecil's poorly offered Light analogies suffering from the same lack.

That's pretty funny, Richard, since you are agreeing with me 100%
in this posting. Glass that allows glare loses some light in the
rearward direction (reflections). Glass that doesn't allow glare
ensures that all the light reaches the object. Unmatched RF systems
can allow reflected power to be lost from the load. Matched RF
systems ensure that all the power reaches the load (minus line
losses).

You have never said anything worthwhile that technically disagrees
with me. Your only objections are to my style (witness the above).
--
73, Cecil, W5DXP



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Richard Clark wrote,

My EM guys, Physics types, [from my working days] indicated that the
three dielectric interfaces, adhesive to glass to adhesive, all with
different dielectric coefficients create reflections at the boundaries.

Hi Dave,

Poor theory. Reflection is not loss. There are reflections galore on
a radiator that supports the Standing Wave and yet with a large enough
metal surface it is nearly 100% radiative.

As for this boundaries explanation, those "Physics types" clearly did
not have any working knowledge (experience) - about as useful as
Cecil's poorly offered Light analogies suffering from the same lack.
I further note that none of this indicts clear glass (which may have
been a semantic issue) to the tune of nearly 1dB.

73's
Richard Clark, KB7QHC


Hi Richard,
absent any numbers on the loss tangent of automobile window
glass at the frequency in question, any estimate of loss is just a guess.
73,
Tom Donaly, KA6RUH

On Tue, 06 Apr 2004 12:31:04 -0500, Cecil Moore
wrote:

Richard Clark wrote:
Cecil's poorly offered Light analogies suffering from the same lack.

That's pretty funny, Richard, since you are agreeing with me 100%
in this posting. Glass that allows glare loses some light in the
rearward direction (reflections).

Everything you write about light is pretty funny; your sheer lack of
experience is revealed where you can't name what frequency glare is.
Care to hazard a guess? Or do we get quotes from you suitable for
Thurberian response? :-)