RadioBanter - View Single Post - 50 Ohms "Real Resistive" impedance a Misnomer?

July 24th 03, 02:43 AM

(Richard Harrison) wrote in message ...
Art Unwin wrote:
"It is in this area that I view stagger tuning or coupling to be
efficient in character."

This is a struggle against nature. Like the double-tuned stagger
frequency transformer, the wider the frequency separation, the less the
coupling.

Richard it is no use bringing up the subject that you have told Art
e.t.c.
As far as I am concerned you do not have the faintest idea of what my
antenna consists of ...or..you don,t know what you are talking about
However you are in good company as the whole idea has been trashed by
the newsgroup and without dissention it was agreed that I have no
credability
Can't type either) So why are you bringing up the idea again of
antenna coupling?
That particular horse is dead.
You would be better off looking at your books and pulling out a
statement verbatum regarding a conjugate match or the date of Termans
birthday than trying to bait me on a subject where I have already
received a hiding from resident gurus and bypassers alike.

Art.

Another item promotes coupling in a transformer. It is placement of the
coils so they share flux. An opposite phenomenon is at work for Art, as
I`ve told him for the nth time. A small loop has a null in its radiation
perpendicular to the plane of the loop. Art`s loop shares the plane of
his dipole. The loop is suspended form the dipole and actually shares
conductor.

The dipole has maximum desired radiation perpendicular to the plane
containing the loop. At horizontal and low-angle directions to the
earth, this is the direction of the loop`s null. No way could radiation
from the loop reinforce dipole radiation.

In a yagi, the reflector is tuned lower in frequency and the director is
tuned higher in frequency than the driven element. The purpose of this
detuning is to get proper phasing between the elements so that director
directs and the reflector reflects and not vice versa. But, in the case
of the yagi, radiation of all the rods is in the same plane that they
share and that contains the desired direction of signal transmission /
reception.

In a dipole which shares conductor with one side of a suspended loop,
the only possible loop contribution to the dipole`s radiation is
straight up, or straignt down, or toward the ends of the dipole. This
could help it approach an isotropic antenna more closely. The isotropic
has about 2 db less gain than a dipole alone. Or, a slight gain toward
the earth, the zenith, or the dipole ends might be realized, as stated
before.

Best regards, Richard Harrison, KB5WZI