Loading Coils; was : Vincent antenna
 

Michael Coslo wrote:
Cecil Moore wrote:
If you would just look at my simple stub example, you would
understand where those missing degrees are. They are at the
coil to stinger junction and may represent more than half
the degrees in the antenna. The coil represents a good portion
of the rest of the degrees. The stinger is usually about 11
degrees long.

I don't understand. At the junction between the two?

The loading coil has a Z0 in the thousands of ohms, e.g.
about 4000 ohms for my 75m Texas Bugcatcher coil. The
stinger's Z0 is a few hundred ohms, e.g. 350 ohms. There
will be a phase shift at the 4000 ohm to 350 ohm junction.
It is a free, lossless phase shift from Mother Nature.

Does this mean that an extremely short antenna could be built that
consisted of several small coils, and lots of junctions?

No, you gain degrees at the high to low impedance junction.
You *lose degrees* at the low to high impedance junction.
That's why you need more coil for a center-loaded antenna
than you do for a base-loaded antenna.

And remember that the radiation efficiency depends upon
*physical* length, not electrical length.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

On 5 Dec, 06:29, Cecil Moore wrote:
Roy Lewallen wrote:
Take a look at my 2005 measurements and see if you can do what Cecil and
Yuri failed to do coherently -- use the "replacement" concept and
explain where the missing degrees went.

I didn't fail to explain them, Roy, you just failed to listen
to reason, ploinked me, and started uttering Big Lies about
me.

In my 75m mobile base-loaded bugcatcher antenna:
1. The coil occupies ~25 degrees of antenna.
2. The impedance discontinuity at the coil to stinger
junction provides a ~44 degree phase shift.
3. The stinger occupies ~11 degrees of antenna.

At resonance the antenna is electrically
25+54+11 = 90 deg long even though it is physically
only ~12 degrees long.

All of the "missing degrees" appear at the impedance
discontinuities but you already know that since I
explained this to you two years ago.
--
73, Cecil http://www.w5dxp.com


Gentleman.
An update on Gaussian antennas
Guffaws heard

Took apart my helix wound on a garbage can for 160M
which was 1.5 :1 form wound and decided to make it
in horizontal element form.
Wires were 28 feet in length and I wound them tightly on
a 2 inch plastic pipe with pairs of wires,
two wires up and two wires down.
Made three of these assemblies and let the insulated wire "spring"
so I could place them on a 20 foot plastic pipe ,again 2 inches
diameter
and then connected them up with wire nuts.
When near to the ground the resonant impedance was in the
hundreds and changed little in the hunt for a sweet spot.
When placed 70 feet up impedances went to pot so I made
another two assemblies and connected them to the antenna assy.
without changing the overal length. Impedance was less than 2:1
across the 160 metre band. This resonance point I would call a
std resonance, where as, the ground measured a anti resonance.
As you can see the antenna revolves arounda full wave and
thus does not require a ground plain and conforms with
my Gaussian definition for a radiator.( The radiator can be any
size ,shape or elevation as long as the material is diamagnetic
and in a state of equilibrium)
( This, by the way, can be seem as what Einstein was looking for
twenty years but without success)
As you can see proximity to ground upset the equilibrium,but when
raised
to 70 feet the length aproached the 7/4 WL and probably woulD have
finished up around there if I could raise it in excess of a 1/2WL.
Wire used was #18 insulated house wire.
The antenna has multi resonances with the resistive resonances
increasing in value until it was a maximum at 160 M.
Snow has arrived so I will stay with this form until spring
while working on it to make it an ALL FREQUENCY GAUSSIAN
DIRECTIVE ANTENNA.
Covered the element with plastic sheeting because freezing
rain would cling to the windings and make it heavy.


Got any opinions or comments that could add to my understanding
of my present antenna? Don't mind contraversy as any discussion
tends to shed light in unexpected corners.
Best regards
Art

Loading Coils; was : Vincent antenna
 

On Wed, 05 Dec 2007 07:44:11 -0600, Cecil Moore
wrote:

Richard Clark wrote:
Cecil Moore wrote:
Equipment was a dual-trace 100 MHz O'Scope.

What make, model?

Leader LBO-518
Using what probes?

Loading Coils; was : Vincent antenna
 

Richard Clark wrote:
Using what probes?

Toroidal current pickup coils designed by W7EL
with the standard voltage probes.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Roy Lewallen wrote:
Take a look at my 2005 measurements and see if you can do what Cecil and
Yuri failed to do coherently -- use the "replacement" concept and explain
where the missing degrees went.


"Cecil Moore" wrote

If you would just look at my simple stub example, you would
understand where those missing degrees are. They are at the
coil to stinger junction and may represent more than half
the degrees in the antenna. The coil represents a good portion
of the rest of the degrees. The stinger is usually about 11
degrees long.
_______________

The coil provides whatever inductive reactance is needed to make the
RADIATOR (the stinger, and mounting stub for the coil+stinger, if used)
functionally non-reactive as a system, at its feedpoint.

An 11-degree radiator/stinger doesn't radiate the power that will flow into
it any differently whether the system is resonant or not. However a
resonant system supplies more of the available source power to the stinger,
so that it CAN be radiated.

The fact that adding a coil to an 11-degree radiator produced the system
reactance a 90-degree, unloaded, linear radiator does not mean that the coil
and its junction to the stinger have supplied the "missing electrical
degrees" to the antenna system. The RADIATOR is still only 11 degrees long,
and will have same radiation resistance and relative field pattern,
regardless of the coil. The coil only supplied a non-reactive condition at
the system feedpoint.

Note that unloaded, linear radiators also can be naturally resonant at
physical/electrical lengths greater than ~90 degrees. Does that make the
same coil that can load an 11-degree stinger to resonance also responsible
for those greater "missing degrees?"

The effort spent here in bitter argument about phase shift through a coil,
and missing degrees would be better spent on methods of improving the
radiation resistance of such systems, and reducing the matching and r-f
ground losses that limit their performance.

RF

Loading Coils; was : Vincent antenna
 

Cecil, W5DXP wrote:
"However, the side that believes that a coil replaces all of the missing
antenna degrees is wrong."

It certainly can!

I worked the summer of 1949 at the KPRC-KXYZ broadcasting plant at Deep
Water (Pasadena), Texas. An operator there, J.L. Davis, W5LIT, had a war
surplus ART-13 in the trunk of his new 1949 Ford which was powerd by a
PE-103 dynamotor, or something of the sort.

Antenna was a cane fishing pole wound from end to end with wire except
for some bare pole to bolt on his rear bumper.

It radiated very well without any stinger or mast. Its problem was high
Q. When J.L. Cranked up the modulation, he would at times light up the
atmosphere with ionization from the tip of his antenna.

I`ll give you another example of a larger diameter but much shorter coil
used as the sole antenna. It is the radial mode helix which has a
carefully selected diameter and pitch to cause radiatiation at right
angles to its axis. It is shown in Fig. 17-5 on page 407 of "The
Complete Broadcast Antenna Handbook" by John E. Cunningham. It was once
used by TV and FM stations. Horizontally polarized, its popularity has
waned.

Best regards, Richard Harrison, KB5WZI

Loading Coils; was : Vincent antenna
 

"Roy Lewallen" wrote in message
...
AI4QJ wrote:

Roy, I will definitely be going through those archives. However, we have
seen many antennas in which the entire antenna is wound as a spiral with
a relatively large pitch in order to shorten it. In this case, the entire
antenna could also be considered an "inductor". For that matter, even a
straight length of antenna wire could be considered a 1/2 turn
"inductor". Ignoring the latter extreme example for now, could not the
common spirally wound antenna be considered an inductor that "replaces"
the entire antenna? I'm not saying it is a "good" antenna but it could be
90 degrees long and have the same distribution of standing wave current
as a straight antenna. Also, I wonder if we are arguing semantics over
the definition of "inductor".

Definition is definitely a part of the problem. I don't have so much
trouble with variations of defining an "inductor" as I do with the concept
of "replacing" part of an antenna or measuring an inductor in "electrical
degrees". A straight wire and a coiled wire both have the property of
inductance, but in general a coiled wire will radiate less than a straight
one of the same inductance. The coupling to ground or the other half of
the antenna is also different for straight and coiled wires. So one
doesn't directly "replace" the other. The concept of "replacement" is
overly simplistic and, when extrapolated, can lead to erroneous
conclusions (or in the case of Cecil's and Yuri's theories, multiple and
contradictory conclusions).

Take a look at my 2005 measurements and see if you can do what Cecil and
Yuri failed to do coherently -- use the "replacement" concept and explain
where the missing degrees went.

Roy Lewallen, W7EL

Clouding the issue. "Lost" degrees were not the controversy.

The main argument was (W8JI, W7EL et al) that current along the loading coil
in the resonant quarter wave radiator is constant or very close to, while
(W9UCW, K3BU, W5DXP et al) found that it diminishes toward the stinger by as
much as 40 - 60 %. The rest was nitpicking and drive around the fact trying
to "prove" us wrong or inaccurate or making up "our" theories.

The replacement degrees idea was used to demonstrate the behavior or effect
of the loading coil on the current distribution along the coil and ANTENNA
which is reflective of performance/efficiency of the loaded radiator
(proportional to the area under the current curve distribution).

The "guru" crowd can't seem to swallow this and are harping on this or that,
while any turkey ham can see the effect by grabbing the loading coil and
feeling the heat, more at the bottom than at the top.

The rest of discussions led to better understanding of what is happening in
the loaded element and thanks to Cecil for digging into it and 'splaining
the possible effects.

Which brings me to another subject: standing wave vs. traveling wave
antennas, but that is another story which I would like to get deeper
understanding.

So the argument that missing degrees to fourth decimal point are not there
is just to mask the admission of being grossly wrong and admitting to it and
perhaps even giving some credit where it's due.

Glad that W8JI does not wear inquisitor mantle, or you would have fried by
now Cecil :-)

73 Yuri, K3BU.us

Loading Coils; was : Vincent antenna
 

On 4 Dec, 23:34, Roy Lewallen wrote:
AI4QJ wrote:

Roy, I will definitely be going through those archives. However, we have
seen many antennas in which the entire antenna is wound as a spiral with a
relatively large pitch in order to shorten it. In this case, the entire
antenna could also be considered an "inductor". For that matter, even a
straight length of antenna wire could be considered a 1/2 turn "inductor".
Ignoring the latter extreme example for now, could not the common spirally
wound antenna be considered an inductor that "replaces" the entire antenna?
I'm not saying it is a "good" antenna but it could be 90 degrees long and
have the same distribution of standing wave current as a straight antenna.
Also, I wonder if we are arguing semantics over the definition of
"inductor".

Definition is definitely a part of the problem. I don't have so much
trouble with variations of defining an "inductor" as I do with the
concept of "replacing" part of an antenna or measuring an inductor in
"electrical degrees". A straight wire and a coiled wire both have the
property of inductance, but in general a coiled wire will radiate less
than a straight one of the same inductance. The coupling to ground or
the other half of the antenna is also different for straight and coiled
wires. So one doesn't directly "replace" the other.

Where on earth did this little gem come from?
W8ti states a similar thing when he says a wire should be as straight
as possible . I suspect that some conditions and definitions are to
be added before such a generalized statement can be made.
Seems like the beginning of an old wives tale that can produce a
thread
by Cecil that could last a decade before it is finally snuffed out
unless the statement is securely bound by a definition where there
can be no misunderstanding especially by those well versed in
relatavistic sciences.Let's face it radiation can be generated
from a point source which can be seen as three dimensional where as
a straight wire is two dimensional
Art KB9MZ





The concept of
"replacement" is overly simplistic and, when extrapolated, can lead to
erroneous conclusions (or in the case of Cecil's and Yuri's theories,
multiple and contradictory conclusions).

Take a look at my 2005 measurements and see if you can do what Cecil and
Yuri failed to do coherently -- use the "replacement" concept and
explain where the missing degrees went.

Roy Lewallen, W7EL

Loading Coils; was : Vincent antenna
 

On 5 Dec, 07:49, (Richard Harrison) wrote:
Cecil, W5DXP wrote:

"However, the side that believes that a coil replaces all of the missing
antenna degrees is wrong."

It certainly can!

I worked the summer of 1949 at the KPRC-KXYZ broadcasting plant at Deep
Water (Pasadena), Texas. An operator there, J.L. Davis, W5LIT, had a war
surplus ART-13 in the trunk of his new 1949 Ford which was powerd by a
PE-103 dynamotor, or something of the sort.

Antenna was a cane fishing pole wound from end to end with wire except
for some bare pole to bolt on his rear bumper.

It radiated very well without any stinger or mast. Its problem was high
Q. When J.L. Cranked up the modulation, he would at times light up the
atmosphere with ionization from the tip of his antenna.

I`ll give you another example of a larger diameter but much shorter coil
used as the sole antenna. It is the radial mode helix which has a
carefully selected diameter and pitch to cause radiatiation at right
angles to its axis. It is shown in Fig. 17-5 on page 407 of "The
Complete Broadcast Antenna Handbook" by John E. Cunningham. It was once
used by TV and FM stations. Horizontally polarized, its popularity has
waned.

Best regards, Richard Harrison, KB5WZI

The resultant vector of all vectors involved with radiation can NEVER
be at right angles to the axis of a radiator. PERIOD
Art KB9MZ

Loading Coils; was : Vincent antenna
 

"art" wrote
The resultant vector of all vectors involved with radiation can
NEVER be at right angles to the axis of a radiator. PERIOD
___________

Are you thinking that your statement above applies to the radiation from the
vertical monopoles used by commercial AM broadcast stations ?

Their performance has been accurately and carefully measured going back 70+
years, and the "resultant vector" of their radiation at right angles to the
radiator axis certainly is not zero.

RF