"Richard Fry" wrote in message
...


An antenna * system * does not need to have X number of degrees to be
resonant. It only needs to have ~zero reactance at its feedpoint --
which, for electrically short AND long radiators can be achieved by use of
a suitable matching network.

Such networks don't add or subtract electrical degrees, however. They
only reduce/cancel the natural reactance of the physical radiator in use.

RF

The above post is without doubt, the clearest, cleanest and to the point
statement of any made to date in this whole silly chain of posts! It
demonstrates a clear and firm grasp of antenna theory. Something that is so
obviously missing from 99 percent plus of the bulk of posts on the subject!

Dean -- W4IHK

Dean Craft wrote:
The above post is without doubt, the clearest, cleanest and to the point
statement of any made to date in this whole silly chain of posts! It
demonstrates a clear and firm grasp of antenna theory.

A self-resonant coil is obviously 90 degrees long. If one
removes 5% of the turns and replaces them with a stinger
to bring the system back to resonance at the same frequency,
do you really believe the coil has magically changed from
90 degrees long to zero degrees long?
--
73, Cecil http://www.qsl.net/w5dxp

"Cecil Moore"
A self-resonant coil is obviously 90 degrees long.
_____________

A coil is not the electrical equivalent of a linear, physical, ~90-degree,
self-resonant radiator. How well do you expect your self-resonant coil to
radiate?

When you add a stinger to a coil, it is the stinger that radiates the great
majority of the applied power. The coil just makes it possible/practical
for the tx to supply r-f power to that antenna system that the stinger CAN
radiate, by improving the Z match between the source and the feedpoint.

RF

Dean Craft wrote:

SNIPPED

The above post is without doubt, the clearest, cleanest and to the point
statement of any made to date in this whole silly chain of posts! It
demonstrates a clear and firm grasp of antenna theory. Something that is so
obviously missing from 99 percent plus of the bulk of posts on the subject!

Dean -- W4IHK



Dean, maybe we can start a discussion about the missing 1%

"Something that is so obviously missing from 99 percent..."

"Dave" wrote in message
. ..
Dean Craft wrote:

SNIPPED

The above post is without doubt, the clearest, cleanest and to the point
statement of any made to date in this whole silly chain of posts! It
demonstrates a clear and firm grasp of antenna theory. Something that is
so obviously missing from 99 percent plus of the bulk of posts on the
subject!

Dean -- W4IHK



Dean, maybe we can start a discussion about the missing 1%

"Something that is so obviously missing from 99 percent..."


I have all but given up on that possibility. If its not heated immature
school yard rhetoric driven by obvious professional jealousy, then its mind
playing games just as has appeared since my earlier post. The troll effect
all too frequently takes over and destroys any serious chain of thought.

Dean -- W4IHK

Richard Fry wrote:
"Such networks don`t add or subtract electrical degrees, however. They
only reduce/cancel the natural reactance of the physical radiator in
use."

True if the only mismatch is reactance. A too-long antenna can be
electrically shortened for matching purposes by tuning it to resonance
with the proper series capacitance. A too-short antenna can be
electrically lengthened for matching purposes by tuning it to resonance
with the proper series inductance.

Reactance varies quickly near the resonant length. Radiation resistance
varies more slowly tending to increase at a steady rate as the antenna
is lengthened.

What radiates is current in a length of antenna. What gets current into
an antenna is a conjugate match. Reactance is zeroed out, and source and
load resistances are matched. That`s what`s needed for maximum power
transfer between generator and antenna.

Analysis may have been more abundant than needed for practical purposes.

The velocity of current through a coil has been disputed. Some said it
was almost instantaneous. That was new to me. The nature of inductance
is to produce counter emf which by Lenz`s law opposes current into an
inductance and temporarily delays current changes in an inductance. Only
in a pure resistance is there instantaneous correlation between voltage
and current.

It is believed that the speed of light "c" is a speed limit on
electromagnetic waves. An action in one place must have a delayed
response elsewhere depending on distance.

I can imagine a wave launched at one of an inductor sweeping across its
length and ignoring the round and round path of the wire, but I don`t
know of any of the old authors in my collection who say that such a
short-cut happens. Conductors are the source of free electrons which
permit current flow and my experience is that electricity goes where it
is wired.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:
I can imagine a wave launched at one of an inductor sweeping across its
length and ignoring the round and round path of the wire, but I don`t
know of any of the old authors in my collection who say that such a
short-cut happens. Conductors are the source of free electrons which
permit current flow and my experience is that electricity goes where it
is wired.

Consider a tank circuit link coupled to the outside world.
There are probably negligible free electrons flowing from
primary to secondary. Yet efficient energy transfer occurs
when the coils are tightly coupled.

In a loading coil, each turn is tightly coupled to the
adjacent turn causing part of the current to be the result
of the fields rather than wire path. That's why the VF of
the loading coil is roughly double what it would be for
"round and round the coil" calculations. The VF for a 75m
bugcatcher coil appears to be in the ballpark of 0.04 which
is a far cry from the straight across 1.0 or even 0.5
--
73, Cecil http://www.qsl.net/w5dxp

On Mon, 1 May 2006 22:59:20 -0500, (Richard
Harrison) wrote:

Richard Fry wrote:
"Such networks don`t add or subtract electrical degrees, however. They
only reduce/cancel the natural reactance of the physical radiator in
use."

True if the only mismatch is reactance. A too-long antenna can be
electrically shortened for matching purposes by tuning it to resonance
with the proper series capacitance. A too-short antenna can be
electrically lengthened for matching purposes by tuning it to resonance
with the proper series inductance.

Reactance varies quickly near the resonant length. Radiation resistance
varies more slowly tending to increase at a steady rate as the antenna
is lengthened.

What radiates is current in a length of antenna. What gets current into
an antenna is a conjugate match. Reactance is zeroed out, and source and
load resistances are matched. That`s what`s needed for maximum power
transfer between generator and antenna.

Analysis may have been more abundant than needed for practical purposes.

The velocity of current through a coil has been disputed. Some said it
was almost instantaneous. That was new to me. The nature of inductance
is to produce counter emf which by Lenz`s law opposes current into an
inductance and temporarily delays current changes in an inductance. Only
in a pure resistance is there instantaneous correlation between voltage
and current.

Constraining the discussion to lumped circuit theory, the delay that
you speak of would seem to be relevant if one is measuring transient
response. However, for a steady-state a.c. current, is it not more
appropriate to describe the relationship as a phase lag between the
current through and the voltage across the inductor? Further, is it
not the case that such phase difference is nominally fixed at near 90
degrees (for a high Q inductor), and is it not true that the velocity
is nonetheless at the speed of light?


It is believed that the speed of light "c" is a speed limit on
electromagnetic waves. An action in one place must have a delayed
response elsewhere depending on distance.

I can imagine a wave launched at one of an inductor sweeping across its
length and ignoring the round and round path of the wire, but I don`t
know of any of the old authors in my collection who say that such a
short-cut happens. Conductors are the source of free electrons which
permit current flow and my experience is that electricity goes where it
is wired.

Best regards, Richard Harrison, KB5WZI

We haven't been missing any degrees around here.
We hit the low 90's , while even still in late April.
It's May now, and still no obvious loss of degrees.
Feels like summer, the grass is green, and I feel
quite warm most every day. It's those people up
far north that miss degrees.
MK