On 2/27/2011 11:03 PM, Richard Clark wrote:
On Sat, 26 Feb 2011 07:30:00 -0800 (PST),
wrote:

Hi Wimpie,

This may
require another approach then you should use in a professional
environment. If you prefer that, Edaboard.com (just an example) is a
more suitable place.

Now the result is a professional reaction of Norbert:

Curious combination of conflicting sentiments, there. What is
suitable, and how should we recognize it?

Radiation resistance (no coupling with other objects) will be about 1
mOhm.

There are many source for computation, I chose one that closely agrees
with several at hand. Perhaps I made an entry error, so I will take
the opportunity to examine that possibility he
Rr = 80 · pi² · (dl/lambda)²
80 · 9.87 · (2/80)²
790 · (0.025)²
790 · 0.0006
0.49 Ohm

Of course, the possibility of mis-entry remains, and cross checking is
helpful given an in dependant validation. If I examine my text
further it uses as an example a smaller loop at a lower frequency
dl = 1m
F = 1MHz
(lambda = 300)
resulting in
Rr = 0.0084 Ohm
which is roughly 10 times your computed radiation resistance for a
larger loop at a smaller wavelength.

Now, having said that, and examining my text for further possibilities
of error, I find that, yes, I made an error. My computation was based
for an electric dipole, not a loop. Let us examine the Rr for a loop
from the equation from the same source:
Rr = 320 · pi^6 · (r/Lambda)^4
320 · 961 · (1/80)^4
307,645 · 2.44^-8
0.0075 Ohm
This, too, is very different from your calculation, but certainly that
error is eclipsed by my own first reckoning. However, what does this
say about efficiency based upon the original design (but computed for
another)?

However, I did first ask Norbert for the equation used and the
parameters entered. Testing those results did not appear to be
appealing in the face of contradicting testimonial. It should come as
no surprise that many testimonials are tested here. Testimonials
stand or fall in such tests, and those tests are retested (as has
given rise to this and your response).

Curiously we entered into this with how the loop has superior
qualities over the standard dipole, and then the same loop is cited as
being very inefficient. How such contradictions are held within the
space of a short thread is certainly a denial of engineering
professionalism, but denial is not the standard of merit that is
typically lauded in this forum. A hearty defense of wounded ego
raises suspicion even further.

One consequence of that demurral brings us to a rather remarkable
insight in comparing the radiation resistance of the electric dipole
to the loop within the same spread of the loop (and in certainly a
smaller volume of space). The electric dipole enjoys 60 times more
radiation resistance that certainly impacts efficiency to the same
degree. This, of course, presumes no further errors in computation or
application.

73's
Richard Clark, KB7QHC


Wimpie is right, Richard.

Please go back to your laboratory and speak to someone who understands
your dumb-ass dialect. Also, please don't discourage those who are
trying to contribute their experiences here. Try to be positive for a
change.

John