Discussion:
Distributed Loaded Monopole-technology based antennas
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Glenn Møller-Holst
2006-07-01 15:59:53 UTC
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Regarding a new philosophy for constructing shortened antennas.

Have somebody experience with Distributed Loaded Monopole-technology
based antennas.

Please look on slide number 10, 19, 24, 53:
http://www.uri.edu/news/vincent/boxboro_files/frame.htm

Slide 25 shows how it is constructed:
http://www.uri.edu/news/vincent/boxboro_files/frame.htm

According to the following test, the antenna should be good - and maybe
better than other shortened antennas. 70% efficiency for a 1/4 wave
shortened antenna, is that good?:

-

April 28, 2005 Navy gives URI’s small antenna big results
http://www.uri.edu/news/releases/?id=3126
Quote: "...
In addition, the gain of Vincent’s capacity Top Hat DLM antenna, which
incorporates a helix, a load coil, a capacitive top hat utilizing radial
spokes at the top of the antenna and a horizontal plane was nearly
identical to the ideal quarter wave antenna. Its bandwidth was greater
than 5 percent of the operating frequency and the antenna is more than
70 percent shorter than an ideal quarter wave antenna.

Vincent’s standard DLM antennas with a standard helix and load coil were
also tested at various frequencies. All exhibited gains nearly equal to
the ideal antenna with bandwidths of 3 to 10 percent. The antennas were
33 to 40 percent shorter.
..."

-

Test Report of U.R.I. DLM ANTENNAS
By The NAVAL UNDERSEA WARFARE CENTER Of Newport, Rhode Island At The
NUWC Fishers Island, New York One MileTest Range March 31, 2005.
Robert Vincent Dept. Physics University of Rhode Island Kingston, RI 02881
http://www.uri.edu/news/vincent/report05/testreport.pdf
Quote: "...
The overall data error of this facility is less than 0.2db. in any one
measurement.
...
The reference monopole can considered as a perfect monopole operating
over a perfect ground system. NUWC calculates this reference antenna
level over their calibrated one mile range.
...
Antenna type Gain db**
7MHz Plano Spiral Top Hat —Super DLM“ +.06db (100% virkningsgrad)
...
7 MHz Standard DLM #1 -1.71db (67% virkningsgrad)
7 MHz Standard DLM #2 -1.56db (70% virkningsgrad)
...
10 MHz Standard DLM #1 -1.14db (77% virkningsgrad)
10 MHz Standard DLM #2 -1.37db (73% virkningsgrad)
...
Percentage of operating antenna length as compared to a ³ wave monopole
is indicated below. .

Antenna type %1/4 wave
Plano Spiral Top DLM (super DLM) 50%
Standard DLM 33%
..."

/Glenn
Glenn Møller-Holst
2006-07-01 16:09:24 UTC
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Additional information:

The antenna does not have a feeding matching network and it is rather
broad-banded for a shortened antenna to be. Or is it? - please compare i
with other shortened antennas.

/Glenn
Richard Clark
2006-07-01 17:36:33 UTC
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Post by Glenn Møller-Holst
Regarding a new philosophy for constructing shortened antennas.
Hi Glenn,

The term here that seems to fit is poser. It is a variant of poseur
if that term is more familiar. This
Post by Glenn Møller-Holst
Test Report of U.R.I. DLM ANTENNAS
By The NAVAL UNDERSEA WARFARE CENTER Of Newport, Rhode Island At The
NUWC Fishers Island, New York One MileTest Range March 31, 2005.
is notable for having no signature page showing its bona fides. A
University of Rhode Island grade two technician is NOT an authority at
that facility.

Both the "report" and the other links all show very poor skills at
writing much less reporting. For instance, the "report" completely
omits the characteristic Z of the antenna. Is this antenna range
facility so shy of equipment that this notable specification was left
unmeasured? Even a standard quarter wave radiator is not a 50 Ohm
match.

This, and the rambling style that wanders the landscape in describing
this invention hardly inspires confidence in this moonlight episode of
using those facilities on the sly.

73's
Richard Clark, KB7QHC
Frank's
2006-07-03 00:51:20 UTC
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Post by Richard Clark
Post by Glenn Møller-Holst
Regarding a new philosophy for constructing shortened antennas.
Hi Glenn,
The term here that seems to fit is poser. It is a variant of poseur
if that term is more familiar. This
Post by Glenn Møller-Holst
Test Report of U.R.I. DLM ANTENNAS
By The NAVAL UNDERSEA WARFARE CENTER Of Newport, Rhode Island At The
NUWC Fishers Island, New York One MileTest Range March 31, 2005.
is notable for having no signature page showing its bona fides. A
University of Rhode Island grade two technician is NOT an authority at
that facility.
Both the "report" and the other links all show very poor skills at
writing much less reporting. For instance, the "report" completely
omits the characteristic Z of the antenna. Is this antenna range
facility so shy of equipment that this notable specification was left
unmeasured? Even a standard quarter wave radiator is not a 50 Ohm
match.
This, and the rambling style that wanders the landscape in describing
this invention hardly inspires confidence in this moonlight episode of
using those facilities on the sly.
73's
Richard Clark, KB7QHC
NEC indicates the input impedance is about 18 ohms for the 40 m model.
The gain (with ten 12 ft radials, base 3" above average ground) at
30 deg elevation angle is -3.9 dBi. I used a distributed helix with the GH
card,
but for the 2nd inductor a lumped element inductor, Q = 300. The value
for the 2nd inductor was much higher than the recommended 15 uH. at
about 36 uH.

An unloaded monopole of the same height, same radial system, has a gain
of -2.9 dBi at 30 deg elevation angle. Input impedance 6.2 - j748.
A two element matching network, inductor Q 400 (same Q as the
base helix) has a loss of 1.7 dB for an overall gain of - 4.6 dBi
at 30 deg.

Frank
n***@wt.net
2006-07-02 14:07:21 UTC
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Post by Glenn Møller-Holst
Regarding a new philosophy for constructing shortened antennas.
Have somebody experience with Distributed Loaded Monopole-technology
based antennas.
http://www.uri.edu/news/vincent/boxboro_files/frame.htm
http://www.uri.edu/news/vincent/boxboro_files/frame.htm
According to the following test, the antenna should be good - and maybe
better than other shortened antennas. 70% efficiency for a 1/4 wave
My mobile whip is probably that good on 20m up...
One note....Myself, I think using gain numbers to compare
verticals that are 1/4 wave or less is sort of silly. It's not the
gain that matters. It's the overall system efficiency that really
matters. And yes, 70% is fairly decent for a "short" vertical.
It's enough to not be able to tell a large difference from a full
1/4 wave.
MK
w***@akorn.net
2006-07-04 11:48:10 UTC
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Post by Glenn Møller-Holst
Regarding a new philosophy for constructing shortened antennas.
What is new about it?
That same scheme has been used since the 70's on CB antennas.
Post by Glenn Møller-Holst
Have somebody experience with Distributed Loaded Monopole-technology
based antennas.
http://www.uri.edu/news/vincent/boxboro_files/frame.htm
http://www.uri.edu/news/vincent/boxboro_files/frame.htm
According to the following test, the antenna should be good - and maybe
better than other shortened antennas. 70% efficiency for a 1/4 wave
All of his measurements are seriously lacking substance. I wouldn't
trust them.

To answer your question, there is NOTHING that indicates his method
improves performance, and a great deal that indicates it is far from an
optimum system.
Post by Glenn Møller-Holst
April 28, 2005 Navy gives URI's small antenna big results
http://www.uri.edu/news/releases/?id=3126
Quote: "...
In addition, the gain of Vincent's capacity Top Hat DLM antenna, which
incorporates a helix, a load coil, a capacitive top hat utilizing radial
spokes at the top of the antenna and a horizontal plane was nearly
identical to the ideal quarter wave antenna. Its bandwidth was greater
than 5 percent of the operating frequency and the antenna is more than
70 percent shorter than an ideal quarter wave antenna.
So what, that's nothing special. And who tested it and how was it
compared? Who signed off on the tests? It all reads like snake oil to
me.
Post by Glenn Møller-Holst
Vincent's standard DLM antennas with a standard helix and load coil were
also tested at various frequencies. All exhibited gains nearly equal to
the ideal antenna with bandwidths of 3 to 10 percent. The antennas were
33 to 40 percent shorter.
So what? And who signed off on the tests, and how were they made?
Post by Glenn Møller-Holst
Test Report of U.R.I. DLM ANTENNAS
By The NAVAL UNDERSEA WARFARE CENTER Of Newport, Rhode Island At The
NUWC Fishers Island, New York One MileTest Range March 31, 2005.
Robert Vincent Dept. Physics University of Rhode Island Kingston, RI 02881
http://www.uri.edu/news/vincent/report05/testreport.pdf
Quote: "...
The overall data error of this facility is less than 0.2db. in any one
measurement.
...
The reference monopole can considered as a perfect monopole operating
over a perfect ground system. NUWC calculates this reference antenna
level over their calibrated one mile range.
What do they mean "calculates"??? That's a very odd word, because it
implies they never MEASURED the reference antenna. Also no one states
what the reference antenna was, other than a "perfect monopole over
perfect groundplane". IF it was perfect, that means it was not a real
antrenna. If it was not a real antenna, we are at the mercy of
calculations. I can assure you that is NOT how an antenna test is done
on a test range.

It is also impossible for a significantly shorter antenna to have gain
over a perfect monopole over perfect ground when the antenna under test
uses a real ground and real antenna losses.

In my opinion, the press releases are all bullcrap.

...
Post by Glenn Møller-Holst
Antenna type Gain db**
7MHz Plano Spiral Top Hat -Super DLM" +.06db (100% virkningsgrad)
...
7 MHz Standard DLM #1 -1.71db (67% virkningsgrad)
7 MHz Standard DLM #2 -1.56db (70% virkningsgrad)
...
10 MHz Standard DLM #1 -1.14db (77% virkningsgrad)
10 MHz Standard DLM #2 -1.37db (73% virkningsgrad)
...
Percentage of operating antenna length as compared to a ³ wave monopole
is indicated below. .
Antenna type %1/4 wave
Plano Spiral Top DLM (super DLM) 50%
Standard DLM 33%
..."
Since the 1920's it has been well established a 1/8th wave tall
monopole has about the same FS as a full size antenna when over a very
good ground system.

Big deal.

73 Tom
Wes Stewart
2006-07-04 13:32:32 UTC
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Post by Glenn Møller-Holst
Regarding a new philosophy for constructing shortened antennas.
K1DFT all over again.

I do wonder how he weaseled the Navy into wasting time on this.

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