'Doc wrote in message ...
Richard,
My peashooter is racked. Guess that means I'm just
lurking?


Nah, it means your in your usual position, riding on someone else's shirt tail.

Art, KB9MZ wrote:
"Antenna engineers have become so focussed on the half wave patterns
that they have completely ignored the low efficiency portions at the
ends of the half wave antenna. Future antennas most surely will remove
these low efficient (sic) radiator parts together with the addition of
coupling techniques that will help to move away from the yagi syndrome."

Don`t hold your breath!

Antenna engineers are focussed on 1/2-wave antenna patterns because
those are the patterns produced by 1/2-wave antennas. A half-wave
antenna is resonant without a reflection from the earth or anything
else. Antenna system resonance is essential to remove reactive impedance
to antenna current flow. No current flow, no antenna operation.

The ends of a dipole have nearly zero radiation because current at the
ends is nearly a zero sum of incident and reflected currents.The H-field
is thus cancelled. Radiation ends where the current ends. A 1/4-wave
back from the reflection point, incident and reflected currents are
in-phase and strong radiation is possible.

What Art calls the "yagi syndrome" is a preference for an antenna which
has only one feedline attachment point and gets about as much gain per
length of wire as any. Size is important for wind loading in addition to
antenna cost and performance. The yagi is a big performer in spite of
its small size.

Yagi elements must be nearly 1/2-wave in length because that`s the
minimum length required to accept significant induced current in a
parasitic element=A0far from ground.

If you were to chop off the ends of a 1/2-wave antenna, you would have
to replace them with another mechanism to bring resonance back to the
shortened dipole. These artifices are almost always lossier than the
lost conductor removed from the antenna. A capacitance hat is an
exception, but this is hardly smaller.

At night it is often more rewarding to look for something lost, not
because the site seems probable, but because the search site is the only
illuminated spot.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:

Art, KB9MZ wrote:
"Antenna engineers have become so focussed on the half wave patterns
that they have completely ignored the low efficiency portions at the
ends of the half wave antenna. Future antennas most surely will remove
these low efficient (sic) radiator parts together with the addition of
coupling techniques that will help to move away from the yagi syndrome."

Don`t hold your breath!

Makes me wonder if Art has ever considered cutting-off the unused parts
of the tires on his car. ;-)

73, Jim AC6XG

"Art Unwin KB9MZ" wrote in message
m...
I found it interesting

SNIP

and try to get along rather than looking for
ten seconds of cheap glory.

Art Unwin KB9MZ......XG



Ten seconds of cheap glory is often all you get.

Ed
wb6wsn

In message , Art Unwin
KB9MZ writes

Antenna engineers have become so focussed on the half
wave patterns that they have completely ignored the
low efficiency portions at the ends of a half wave
antenna.

Yes, the midldle high current bit generates the H field, but you forget
that the end high voltage bits are needed to generate the E field. The
antenna 1/4 wave physical length is needed to get these in the correct
phase.

Now it should be possible to make a compact antenna where you can
generate the H field from a current element and the electric field from
a voltage element, making sure that the 1/4 phasing is preserved between
the voltage and current. Naah it wouldn't work

Brian GM4DIJ

--
Brian Howie

Hmmmm
They said that the idea of break dancing was an impossibility but they have
classes for same in East St Louis Students are not allowed to graduate
until thay exhibit the ability of removing a hub cap off of a moving vehicle
!
They probably have the same class in The Goebals
Regards
Art



"Brian Howie" wrote in message
...
In message , Art Unwin
KB9MZ writes

Antenna engineers have become so focussed on the half
wave patterns that they have completely ignored the
low efficiency portions at the ends of a half wave
antenna.

Yes, the midldle high current bit generates the H field, but you forget
that the end high voltage bits are needed to generate the E field. The
antenna 1/4 wave physical length is needed to get these in the correct
phase.

Now it should be possible to make a compact antenna where you can
generate the H field from a current element and the electric field from
a voltage element, making sure that the 1/4 phasing is preserved between
the voltage and current. Naah it wouldn't work

Brian GM4DIJ

--
Brian Howie

Art,

You just received two serious and legitimate responses from Tom and Brian. You
proceeded to trash each of them for their contributions.

How do you expect to get useful input if you are not willing to accept anything
that does not agree with your preconceived notions?

YOU are the one with the loaded pea shooter.

Shame on you!

73,
Gene
W4SZ

Art Unwin KB9MZ wrote:
Hmmmm
They said that the idea of break dancing was an impossibility but they have
classes for same in East St Louis Students are not allowed to graduate
until thay exhibit the ability of removing a hub cap off of a moving vehicle
!
They probably have the same class in The Goebals
Regards
Art

Gene I suspect your Google has yet to be updated
but if not look up Tom's responses to me just for this month. As for Brian I
did not trash him ! I think he said at the end it was impossible ! I suspect
you are a new person on this newsgroup so I suppose one has to accept such
statements and not take to much notice of such bland conclusions.......Now
do you have anything to contribute?
Regards
Art

"Gene Fuller" wrote in message
...
Art,

You just received two serious and legitimate responses from Tom and Brian.
You
proceeded to trash each of them for their contributions.

How do you expect to get useful input if you are not willing to accept
anything
that does not agree with your preconceived notions?

YOU are the one with the loaded pea shooter.

Shame on you!

73,
Gene
W4SZ

Art Unwin KB9MZ wrote:
Hmmmm
They said that the idea of break dancing was an impossibility but they
have
classes for same in East St Louis Students are not allowed to graduate
until thay exhibit the ability of removing a hub cap off of a moving
vehicle
!
They probably have the same class in The Goebals
Regards
Art

Art wrote,

Gene I suspect your Google has yet to be updated
but if not look up Tom's responses to me just for this month.


What responses? I don't normally respond to your posts, Art.
73,
Tom Donaly, KA6RUH

Gene,
Brian is a fellow Brit why would I trash a fellow 'G'
Come to think of it why are you trashing me when you contributed nothing ?
Just try to get along and you are home free
Art

"Gene Fuller" wrote in message
...
Art,

You just received two serious and legitimate responses from Tom and Brian.
You
proceeded to trash each of them for their contributions.

How do you expect to get useful input if you are not willing to accept
anything
that does not agree with your preconceived notions?

YOU are the one with the loaded pea shooter.

Shame on you!

73,
Gene
W4SZ

Art Unwin KB9MZ wrote:
Hmmmm
They said that the idea of break dancing was an impossibility but they
have
classes for same in East St Louis Students are not allowed to graduate
until thay exhibit the ability of removing a hub cap off of a moving
vehicle
!
They probably have the same class in The Goebals
Regards
Art