On Fri, 05 Nov 2004 06:29:58 -0600, Cecil Moore
wrote:
the idea that ... is ridiculous.
The idea that ... is ridiculous.
The idea that ... is ridiculous.
The idea that ... is ridiculous.
The idea that ... is ridiculous.
That all such ideas were expressed by only you ... is typical.

Richard Harrison wrote:
"Ro = 60 times the intergral, zero to pi, ...

Heh, heh, since you don't know the last digit of pi, Roy
probably won't allow you to use it. :-)

Where the radiation resistance Ro is referred to the current maximum.

The point seems to be that the impedance at the current maximum
point includes terms besides radiation resistance. In simplified
form, for a resonant antenna, Rfeed = Rrad + Rloss

Rloss includes I^2*R losses and ground losses and is sometimes
negligible and sometimes not.

For some antenna configurations, Rloss is negligible, so the
feedpoint resistance can be very close to the radiation
resistance, e.g. a dipole in free space.

For other antenna configurations, Rloss is much greater than
the radiation resistance, e.g. an 8 foot center-loaded 75m
mobile antenna.

My screwdriver has approximately a 12.5 ohm feedpoint resistance
on 75m. I consider approximately 10 ohms of that to be ground
loss.
--
73, Cecil, W5DXP

On Fri, 05 Nov 2004 06:29:58 -0600, Cecil Moore
wrote:
the idea that ... is ridiculous.
The idea that ... is ridiculous.
The idea that ... is ridiculous.
The idea that ... is ridiculous.
The idea that ... is ridiculous.
On Fri, 05 Nov 2004 11:46:32 -0600, Cecil Moore
wrote:
Kraus and Balanis also express the same ideas

:-)

Richard Clark wrote:
That all such ideas were expressed by only you ... is typical.

Kraus and Balanis also express the same ideas which are
obvious from the underlying EM wave physics. Although I
don't have Terman's book, apparently so does he.
--
73, Cecil, W5DXP

As another example, the resonant Q of a half-wave dipole is -

Q = Omega * Ld / Rd

or

The reactance of its DISTRIBUTED inductance divided by its DISTRIBUTED
radiation resistance.

Perfectionists may DIRECTLY add conductor resistance to the radiation
resistance because that, too, is a DISTRIBUTED quantity.
---
Reg.

On Fri, 05 Nov 2004 07:45:16 GMT, Richard Clark
wrote:

So much for theories of Rr being modified by loading. I would
appreciate other effort in kind to correct any oversights I've made

Hi All,

Nothing to offer? I didn't think so. :-)

Well, to enlarge the dialogue (but still reject those who prefer to
change the topic to what they CAN prove), any -ahem- "explanations?"

73's
Richard Clark, KB7QHC

I'm chugging Franzia Merlot while cleaning my Colt Python .357 Magnum
and Winchester 30-30 Lever-Action Carbine. :-)
--
73, Cecil
============================

After shooting a rattler do you, Hollywood-fashion, put the weapon to your
lips and blow the smoke out of the barrel? ;o)
----
Reg.

Richard Clark wrote:

On Fri, 05 Nov 2004 07:45:16 GMT, Richard Clark
wrote:


So much for theories of Rr being modified by loading. I would
appreciate other effort in kind to correct any oversights I've made


Hi All,

Nothing to offer? I didn't think so. :-)

I have a question. Can you express the mathematical and/or physical
relationship between Rr and antenna gain? It would sure help to clarify
the point you were trying to make.

Thanks and 73,

AC6XG

Reg Edwards wrote:

W5DXP wrote:
I'm chugging Franzia Merlot while cleaning my Colt Python .357 Magnum
and Winchester 30-30 Lever-Action Carbine. :-)

After shooting a rattler do you, Hollywood-fashion, put the weapon to your
lips and blow the smoke out of the barrel? ;o)

I'm not that primitive, Reg. I use commercial ammo with smokeless
powder. But a friend of mine indeed does use black powder with his
cap and ball revolver.
--
73, Cecil, W5DXP

Richard,

It is not clear just what you were trying to demonstrate, but there was
no obvious connection to Rr. Maximum gain is unrelated to Rr.

Were you looking for validation that you correctly loaded the numbers
into EZNEC?

Looked OK to me.

(OK, so my trolling is not as professional as yours, but I tried.)

If you really are concerned about Rr, then consider the following.

Rr is defined by the equation:

Total power radiated = a*I*I*Rr,

where I and Rr are referred to the same point on the antenna.

For short antennas this reference point is generally taken as the
feedpoint, which is also the current maximum point. There is no loss, so
all power into the antenna is radiated. Therefore the Rr for each of
your perfect world, zero loss examples is proportional to the feedpoint
resistance. Apply an appropriate scaling factor (a) if you want the
correct numbers.

Did you have a question about something?

The bottom line, of course, is that none of this matters in a perfect
world with zero loss. All the power input is shot into space. Please let
us know where we can find that perfect world :-)

73,
Gene
W4SZ



Richard Clark wrote:
On Fri, 05 Nov 2004 07:45:16 GMT, Richard Clark
wrote:


So much for theories of Rr being modified by loading. I would
appreciate other effort in kind to correct any oversights I've made


Hi All,

Nothing to offer? I didn't think so. :-)

Well, to enlarge the dialogue (but still reject those who prefer to
change the topic to what they CAN prove), any -ahem- "explanations?"

73's
Richard Clark, KB7QHC