Glenn Møller-Holst
2006-07-01 15:59:53 UTC
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
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