On 22 Apr, 11:15, (Richard Harrison) wrote:
Art Unwin wrote:

"It was Gauss who started a progression from statics to
eletromagnetics by defining a clustered array as being in equilibrium
within a closed surface in his law of equilibrium.

Clustered array rings a bell! Is clustered array Art`s idea of a
Gaussian antenna?

Richard you should be able to do better than that! A cluster does not
have to have a dimensional reference such as element spacings, It is a
random arangement of parts, that is any parts, not just radiating
elements. Have you heard about cancer clusters and the like?.

J.D. Kraus wrote on page 185 of his 3rd edition of "Antennas" (a must
have):

"I delved into a monumental treatise on "Directional Antennas" by George
H. Brown of RCA. Buried deep in the article was, to me, an astonishing
calculation which indicated that parallel linear dipoles with spacings
of 0.125 wavelengths or less had higher gains than customary larger
spacings."

And he was incorrect with respect to spacings and parallelism and
maximum gain. His observations were purely within the confines of
radiating arrays with parasitic elements only and has nothing to do
with non parasitic arrays. Again Richard you are taking things out of
context since the arrays refered to were not in equilibrium. Period.
Is it possible he can come back to life and write a third volume so
that he can put into todays perspective what many achieved after his
demise that he knew all about before he died? Or are you implying
that nothing new has been found with respect to antennas after he died
by your own personal experience?

Terman in his 1955 opus gives the caveat, on page 906:

"A characteristic of all close-spaced arrays is that as the ratio of
size to antenna gain is reduced, the radiation resistance also goes
down---. The result is a practical limit to the amount of gain that can
be achieved in a compact antenna system, since as the resistance goes
down the fraction of the total power dissipated in the antenna loss goes
up. The Yagi antenna of Fig. 12-39, and the corner reflector, represent
about the best that can be achieved in a practical way with respect to
directive gain in a compact antenna array."

Again Richard you are taking things out of context! And frankly you
are doing it more in an accelerating fashion when compared to your
age.. Terman is refering to close spaced arrays of the parasitic form,
even mentions corner reflectors. Termans phrase of practical
gain is a term often used in the design of parasitic arrays where
practical versus theoretical cannot be attained. Nowhere does Terman
acknoweledge the name of Maxwell,Lorenz e.t.c. in his writings
completly ignoring their contributions in a measure of self
angrandizement.
If he had acknoweledged the works of Gauss he may well as arrived at
arrays in equilibrium
but he could not or would not acknoweledge the works of the masters,
probably because they were European.
Within the envelope of his personal knoweledge what he said 50 years
ago was and is true to those who deny todays advances of science.You
cannot hold on to verbal tails of yesteryear in an effort to impress
those who are skilled in the present day state of the art. Did Terman
discuss satelittes, wifi, the impact of Einstein with respect to
antennas or potential momentum? Ofcourse not, he was not aware of them
because he was of an older generation and his books contain lot of
stuff that is completely out of date in line with cave mans readings.




True today as it was more than 50 years ago.



It just amazes me how you old timers reach back to their school days
and books used in an effort to elevate their own generation by quoting
old books as the testimony that all is known about antennas. This is
akin to sayingt that by their own experience the teachings of Terman
was all encompasing which they themselves could not improve apon which
is very plausable considering the deteriation of brain power of the
constituent members. If you relied on memory instead of personal
thought in you exam days then it becomes obvious that your
position in scientific life will descend faster than you age. If you
are going to continue quoting the written word it is critical that you
write down what the subject matter is so that you don't forget it and
get confused.
Regards
Art



Best regards, Richard Harrison, KB5WZI