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Old October 13th 04, 11:42 PM
Roy Lewallen
 
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Chuck wrote:
. . .
That said, I take exception with your
statement regarding the
bi-directionality of the simulated
coaxial transmission lines in available
NEC(n) engines. Their simulations are
uni-directional - from the input to the
load, but not in reverse.


That is patently false, and can be easily demonstrated. The transmission
line model in NEC (and EZNEC) is a linear network which is completely
bidirectional.

. . .


Please consider the following:

Some years ago - using EZNEC - I
modeled my basic 2 element driver
using a simulated a bi-directional
coaxial phasing line, by placing two
such lines side-by-side - one fed at
the front matching network and
terminated in the rear matching
network, the other fed at the rear
matching network and terminated in
the front matching network. Applying
empirical data to the rear input
(simulating the induced energy), the
ensuing results were consistent in
every way with the empirical model.

While this may or may not be
definitive proof, it does strongly
support my assertion.


. . .


I think some doubt is warrented about both Chuck's measurement ability
(which led him to conclude that his antenna has more gain than
theoretically possible) and his modeling ability.

In September 1997, Chuck sent me the model he created with his pirated
copy of EZNEC. Among other problems, which I pointed out to him at that
time, were wires which intersected at other than a segment junction, and
a wire which was entirely inside another wire, which causes NEC-2 to
give unpredictable and wrong results. (Such errors are now caught by
EZNEC 4.0's Geometry Check, and a model with those errors wouldn't run.)
This, along with more of the history of his attempts to fit his claims
to modeled results, can be found by going to http://groups.google.com
and searching the archives of this group for the articles with the
subject "raibeam antenna models". There, you'll also find my modeling
results for the "Raibeam" and a restatement of the offer I made Chuck
some time before, as follows (from my posting of September 23, 1997):

I made Chuck an offer a while back, as follows: That if he has the
Raibeam tested at a certified antenna range and the results show a
free-space gain of at least 5.5 dBd (7.65 dBi) with simultaneous 25 dB
or greater f/b ratio, I'll pay the test fee. This is performance less
than he claims and less than he claims his model shows. But so far he
hasn't taken me up on the offer.


Although I'm sure the cost of such a test is much greater than it was
when I made the offer, I'll still honor it. Still not interested, Chuck?

Roy Lewallen, W7EL