Howdy NGers,

I was curious about another "miracle" short vertical, being subject of great
interest, patent by Robert Vincent and Physics dept. of University of Rhode
Island. I got up at 4 am, drove to Boxboro ARRL convention and eager to see
what are we missing.

Not much!

Giveaway was opening statement something like: how to make shortened antenna
with more gain (compare to what? I guess light bulb :-)

In the "theoretical" portion of the presentation audience was told that current
across the helical coil decreases away from the feed point, while across
loading coil it stays constant. Due overcrowding of "inventor" I did not
persist in breaking through and asking for enlightenment.

Author claims more gain (familiar), better bandwidth (doesn't get it why) and
small size (of course). Showing measured graphs with current and phase
distribution along the radiator. Works very well! (Many stations worked.)

He showed how to measure current at the antenna using ferrite pickup
transformer way up the antenna and cables to the instrument (handsomely
detuning and distorting the measurements).

I suspect that "broad bandwidth", (SWR 2:1) was achieved thanks to losses in
the coils and dielectric, as "confirmed" by his statement that coils were fried
when power was applied.

What is it? Basically helically wound coil starting from the base, about half
way up the radiator, then piece of straight tubing, than loading coil, then
tubing and in some case top hat (works better :-). Matching to 50 ohms is done
by picking tap at the base, few coil turns up. That is 3D version.

He showed some "2D" versions, having "coils" made of basically coil formed as
hairpin loops instead of classic solenoid, also the loading coil. So kind of 2D
- 3D antenna :-)

I wanted to make a bet that my single loading coil loaded vertical would cream
the "miracle", but there were so many worshippers paying compliments to the
inventor, that I resigned not to stay for the second hour of lecture how to
build it.

I saw no trace of any modeling, just experiments using wrong tools.

So brace yourselves for another "miracle" in the arsenal of very small and more
efficient antennas. It should be a hit with CBers and other suckered users.

So that's it (oh, no chokes in the feedlines), I hope U of RI is proud of this
breakthrough, I can sleep well now. Back to DR1.

Yuri, K3BU
with more info that could have saved lotsa experimenting at
http://www.k3bu.us/loadingcoils.htm

On 14 Aug 2004 23:02:01 GMT, oUsama (Yuri Blanarovich)
wrote:

Howdy NGers,

I was curious about another "miracle" short vertical, being subject of great
interest, patent by Robert Vincent and Physics dept. of University of Rhode
Island. I got up at 4 am, drove to Boxboro ARRL convention and eager to see
what are we missing.

Not much!

Giveaway was opening statement something like: how to make shortened antenna
with more gain (compare to what? I guess light bulb :-)

In the "theoretical" portion of the presentation audience was told that current
across the helical coil decreases away from the feed point, while across
loading coil it stays constant. Due overcrowding of "inventor" I did not
persist in breaking through and asking for enlightenment.

Author claims more gain (familiar), better bandwidth (doesn't get it why) and
small size (of course). Showing measured graphs with current and phase
distribution along the radiator. Works very well! (Many stations worked.)

He showed how to measure current at the antenna using ferrite pickup
transformer way up the antenna and cables to the instrument (handsomely
detuning and distorting the measurements).

I suspect that "broad bandwidth", (SWR 2:1) was achieved thanks to losses in
the coils and dielectric, as "confirmed" by his statement that coils were fried
when power was applied.

What is it? Basically helically wound coil starting from the base, about half
way up the radiator, then piece of straight tubing, than loading coil, then
tubing and in some case top hat (works better :-). Matching to 50 ohms is done
by picking tap at the base, few coil turns up. That is 3D version.

He showed some "2D" versions, having "coils" made of basically coil formed as
hairpin loops instead of classic solenoid, also the loading coil. So kind of 2D
- 3D antenna :-)

I wanted to make a bet that my single loading coil loaded vertical would cream
the "miracle", but there were so many worshippers paying compliments to the
inventor, that I resigned not to stay for the second hour of lecture how to
build it.

I saw no trace of any modeling, just experiments using wrong tools.

So brace yourselves for another "miracle" in the arsenal of very small and more
efficient antennas. It should be a hit with CBers and other suckered users.

So that's it (oh, no chokes in the feedlines), I hope U of RI is proud of this
breakthrough, I can sleep well now. Back to DR1.

Yuri, K3BU
with more info that could have saved lotsa experimenting at
http://www.k3bu.us/loadingcoils.htm

Does it also plug into the house wiring for improved TV reception?
Gotta love junk-science!
Howard

m

Does it also plug into the house wiring for improved TV reception?
Gotta love junk-science!
Howard

Not sure, but it is apparently very easy to scale up or down by simply
reducing/enlarging it on the copier by factor x. No kidding! Apparently works
well into the UHF bands :-) Who needs EZnec.

Can you picture all them wizards joining forces for FracEHDLMCFA gizmo?

Yuri

Yuri Blanarovich wrote:
In the "theoretical" portion of the presentation audience was told that current
across the helical coil decreases away from the feed point, while across
loading coil it stays constant.

I've often wondered at exactly what crossover point a helical coil
turns into a loading coil. If one adds a one inch stinger to a helical
coil, does that turn it into a loading coil? How about a one foot stinger?
Is a one foot long loading coil not a helical coil? Does a one foot long
loading coil really have less phase shift than a one foot long piece of
wire? On a center-loaded mobile antenna, how can the ARCCOS of the current
at the feedpoint be zero degrees and the ARCCOS of the current at the tip
be 90 degrees without there being 90 degrees between the feedpoint and the
tip? (When are you going to invite everyone over to Bar-B-Q that sacred cow?)
--
73, Cecil http://www.qsl.net/w5dxp



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Yuri, your criticism is perfectly sound.

To sum up, the key to antenna radiating efficiency is SIMPLICITY.

The more simple the construction of an antenna the more efficient it will
be.

It is intuitivly obvious. Every complication is sure to introduce loss.
---
Reg

Reg Edwards wrote:
The more simple the construction of an antenna the more efficient it will
be.

An isotropic is pretty simple but I don't know how to feed it. :-)



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I wish someone WOULD come up with a 10-ft vertical for 80 meters with the
same gain and bandwidth as a simple dipole

"Yuri Blanarovich" wrote in message
...
Howdy NGers,

I was curious about another "miracle" short vertical, being subject of
great
interest, patent by Robert Vincent and Physics dept. of University of
Rhode
Island. I got up at 4 am, drove to Boxboro ARRL convention and eager to
see
what are we missing.

Not much!

Giveaway was opening statement something like: how to make shortened
antenna
with more gain (compare to what? I guess light bulb :-)

In the "theoretical" portion of the presentation audience was told that
current
across the helical coil decreases away from the feed point, while across
loading coil it stays constant. Due overcrowding of "inventor" I did not
persist in breaking through and asking for enlightenment.

Author claims more gain (familiar), better bandwidth (doesn't get it why)
and
small size (of course). Showing measured graphs with current and phase
distribution along the radiator. Works very well! (Many stations worked.)

He showed how to measure current at the antenna using ferrite pickup
transformer way up the antenna and cables to the instrument (handsomely
detuning and distorting the measurements).

I suspect that "broad bandwidth", (SWR 2:1) was achieved thanks to losses
in
the coils and dielectric, as "confirmed" by his statement that coils were
fried
when power was applied.

What is it? Basically helically wound coil starting from the base, about
half
way up the radiator, then piece of straight tubing, than loading coil,
then
tubing and in some case top hat (works better :-). Matching to 50 ohms is
done
by picking tap at the base, few coil turns up. That is 3D version.

He showed some "2D" versions, having "coils" made of basically coil formed
as
hairpin loops instead of classic solenoid, also the loading coil. So kind
of 2D
- 3D antenna :-)

I wanted to make a bet that my single loading coil loaded vertical would
cream
the "miracle", but there were so many worshippers paying compliments to
the
inventor, that I resigned not to stay for the second hour of lecture how
to
build it.

I saw no trace of any modeling, just experiments using wrong tools.

So brace yourselves for another "miracle" in the arsenal of very small and
more
efficient antennas. It should be a hit with CBers and other suckered
users.

So that's it (oh, no chokes in the feedlines), I hope U of RI is proud of
this
breakthrough, I can sleep well now. Back to DR1.

Yuri, K3BU
with more info that could have saved lotsa experimenting at
http://www.k3bu.us/loadingcoils.htm


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"Cecil Moore" wrote in message
...
Reg Edwards wrote:
The more simple the construction of an antenna the more efficient it
will
be.

An isotropic is pretty simple but I don't know how to feed it. :-)


From the inside.

Ed
wb6wsn

There were about 80 people at the talk, including a number of hams who are/were
antenna professionals; academics; and so on. I was there for most of it; it was
two hours and thus had the time frame for a substantial brief.

I saw and heard nothing that--in my opinion-- constitutes 'new' or
'revolutionary'. Although the statement "97% efficiency " was made for a
shortened, DLM by Mr. Vincent, I saw no data that supported that claim. I did
not see wide bandwidths in the data. The antennas are small. That claim is
supported.

I did not see any evidence of improvement over the extant art of distributed
loading. What I saw essentially confirms my earlier comments from June and July
in this forum. Note: I was not aware of Mr. Vincent's design for the DLM until
yesterday.

If I missed something, or make a statement here that is factually inaccurate
regarding the statements of Mr. Vincent, apologies ahead of time; and please
fill me in on this forum.

As promised earlier relative to the extant prior art: I draw reference to an
existing, patent pending, commercial antenna by our friends at Astatic (the
microphone company). It is sold by Omnitronics. It is called the "3K Antenna".
The antenna is targeted for CB'ers and truckers, but it also works and is used,
by hams on 10M. It , in appearance, looks identical to some of the DLM antennas
Mr. Vincent presented. There is an inside cutaway which shows, in part , a
vertically oriented helix (linear load); a "midsection"; a loading coil; and a
top whip. I have one here. See:

http://www.astatic.com

Mr. Vincent confirmed that he was unaware of the Astatic antenna until I
mentioned it to him yesterday.

I have offered to elaborate on a critique of Mr. Vincent's technology on the
web, which I will produce, if needed. It may not be necessary for me to educate
this way, as a number of people were/are capable of such assessments based on
the info provided, and Mr. Vincent stated that he will post the PPT of the talk
on the web. Doubtless there will be further independent discussion.

Just as a matter of protocol, in a public talk that has benefited from many
years of guidance under an academic physics department, may I make the
following brief (albeit not complete) suggestions:

1) Understand that a widely spaced helix has air cooling such that the cooling
rate can substantially exceed the heating rate. Therefore the helix may
dissipate heat and does not heat up much. That does not mean the system is
lossless, nor that the efficiency through the helix is high.

2) Never claim that the efficiency of any electronic component as 100%
("lossless through the helix") just because the current profile stays
relatively flat across it, and it doesn't burn up.

3) We have all used chicken wire(as ground screens), but may it strongly be
discouraged. The losses are frequency dependent and often high;

4) Do not discount any ground counterpoise--especially one with 1/8 wave
radials as being --in considering monopoles. It is an antenna system. This is
part of the system;

5) Avoid PVC in monopole construction. At some frequencies the losses are
reasonable, at others it is high. It varies from manufacturer; thickness; and
so on.

6) Do not compare gains on a thin-wire type 1/4 wave monopole to a thick
(diameter) helix-based antenna with a far larger electrical length, over a
lossy, small counterpoise, and infer the efficiency.

7) Do not use wood in the near field when using MF/HF for probe measurements.

My brief thoughts at moment. More later if needed.

73,
Chip N1IR

Hal Rosser wrote:
I wish someone WOULD come up with a 10-ft vertical for 80 meters with the
same gain and bandwidth as a simple dipole

Heck Hal, a 66 ft. vertical for 80m doesn't even have
the same gain as a dipole.



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