MRA Antenna
 

Has anyone taken a look at this antenna? I heard the designer on 75 last
night working a CT0, he says his is 18 foot in diameter. His buddy was
running a 6 foot version and 200 watts and worked the DX as well. He claims
that it is a "minium reactance antenna" thus the name.

http://www.smeter.net/wb4ene/mra-antenna.php

I am only guessing, but there isn't a backpack/portable version of that
antenna available, is there?
And, I just looked at my car, where would I mount that?
Or, is that the kids playhouse, and it obscures the view of the antenna?
grin

Regards,
John

--
I would like to point out, I do appreciate the "Been there--done that!"
posts. Indeed, now your observations, comments and discourse should be
filled with wisdom--I am listening!!!
"Fred W4JLE" wrote in message
...
Has anyone taken a look at this antenna? I heard the designer on 75 last
night working a CT0, he says his is 18 foot in diameter. His buddy was
running a 6 foot version and 200 watts and worked the DX as well. He
claims
that it is a "minium reactance antenna" thus the name.

http://www.smeter.net/wb4ene/mra-antenna.php

Fred,
I seem to recall a simular antenna made by 'MFJ' or 'Hygain',
maybe? No idea how 'well' it worked.
'Doc

On Mon, 11 Apr 2005 21:02:01 -0400, "Fred W4JLE"
wrote:
He claims that it is a "minium reactance antenna" thus the name.
http://www.smeter.net/wb4ene/mra-antenna.php

Hi Fred,

A simple glance at the SWR chart reveals it is in fact a Maximally
Reactive Antenna - at least the initials are preserved.

73's
Richard Clark, KB7QHC

On Wed, 13 Apr 2005 13:35:42 GMT, 'Doc wrote:

Fred,
I seem to recall a simular antenna made by 'MFJ' or 'Hygain',
maybe? No idea how 'well' it worked.
'Doc

I'm having a hard time seeing the "minimal reactance" part of this
design. Looking at the plot of S11 it looks pretty much like any
other antenna with a single resonance.

It has "minimal" reactance at resonance and is highly reactive
elsewhere.

"Richard Clark" wrote in message
...
On Mon, 11 Apr 2005 21:02:01 -0400, "Fred W4JLE"
wrote:
He claims that it is a "minium reactance antenna" thus the name.
http://www.smeter.net/wb4ene/mra-antenna.php

Hi Fred,

A simple glance at the SWR chart reveals it is in fact a Maximally
Reactive Antenna - at least the initials are preserved.

73's
Richard Clark, KB7QHC

A conventional monopole, resonant at about 7 MHz, would completely circle
the Smith Chart for almost two complete revolutions from 1.8 to 30 MHz. I
suppose that is what is meant by "MRA". Apart from that it would be
interesting to know the precise structure details to attempt a NEC model.
It looks suspiciously like the CFA class of antennas.

Frank

Thanks for the reply Richard...

He and his cohart were in the DX window on 75 working a CT0, his buddy had a
6 foot version and both got good reports. The large (18 foot) was running
1500 watts. The smaller one was running 200 watts. As to band conditions, I
later worked an EA with a 5/9+ running 100 watts to a G5RV. I was hoping
one of the EZNEC Gurus would take a look and give us the skinny.


When I looked at the photo, I had deja vu of a CFA.




"Richard Clark" wrote in message
...
On Mon, 11 Apr 2005 21:02:01 -0400, "Fred W4JLE"
wrote:
He claims that it is a "minium reactance antenna" thus the name.
http://www.smeter.net/wb4ene/mra-antenna.php

Hi Fred,

A simple glance at the SWR chart reveals it is in fact a Maximally
Reactive Antenna - at least the initials are preserved.

73's
Richard Clark, KB7QHC

I could probably park my truck out in front of his
house, and do the same thing with my mobile
antenna...My mobile often outperforms my 35-40
ft high dipoles to DX on the lower bands....
To me, it seems to be a very ugly version of a
short top loaded monopole. Nothing more, or
less really....1500 w? He *should* be working dx,
or something is kuput....I work DX mobile with 100w
no problemo. That the "MRA junior" is only 200w doesn't
mean too much to me. He's still twice what I run...
If I were to run a MRA, I would at least install a hot tub
or spa in the middle...Add cup holders...Seats around
the outer section...etc...Shrubbery around the outside to
keep the old lady happy....Hell, with a used JATO engine,
you could probably take a trip in that thing...
I bet it would show on radar, until you ran into the underbelly
of that passing 737-700 that happened to be flying over the
house at the same time...:( Ouch....Can we spell headache?
MK

I'm having a hard time seeing the "minimal reactance" part of this
design. Looking at the plot of S11 it looks pretty much like any
other antenna with a single resonance.

It has "minimal" reactance at resonance and is highly reactive
elsewhere.

It looks to me as if this is a member of the "Super C" antenna...
short, relatively low radiation resistance, and a lot of top-loading
capacitance.

There's an article or two in one of the early ARRL Antenna Compendium
collections (#1 or #2) which analyzes the "Super C" approach, compared
to a short vertical with a more traditional capacity hat made of
straight wires. The analysis seemed to add up to "Probably not worth
the trouble and money", as a similar efficiency can be achieved more
easily and less expensively with the traditional approach. There's a
*lot* of metal in the MRA, and at the price of aluminum this month I
doubt it's a project I'd start.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Dave Platt wrote:

I'm having a hard time seeing the "minimal reactance" part of this
design. Looking at the plot of S11 it looks pretty much like any
other antenna with a single resonance.

It has "minimal" reactance at resonance and is highly reactive
elsewhere.


It looks to me as if this is a member of the "Super C" antenna...
short, relatively low radiation resistance, and a lot of top-loading
capacitance.

There's an article or two in one of the early ARRL Antenna Compendium
collections (#1 or #2) which analyzes the "Super C" approach, compared
to a short vertical with a more traditional capacity hat made of
straight wires. The analysis seemed to add up to "Probably not worth
the trouble and money", as a similar efficiency can be achieved more
easily and less expensively with the traditional approach. There's a
*lot* of metal in the MRA, and at the price of aluminum this month I
doubt it's a project I'd start.

Yea, but put in on a rotator and add some horses and it could double as
a merry-go-round. :-)

ac6xg

In article ,
Jim Kelley wrote:

Yea, but put in on a rotator and add some horses and it could double as
a merry-go-round. :-)

Y'know, I had *started* to add a paragraph to my posting suggesting
that this antenna could be disconnected from its feedline and used as
a jungle gym, but decided that it was a trifle irresponsible to do so.
Too much potentially-sharp metal edges to have around the kiddies, and
there's always that chance that Dad might accidentally key up QRO at
the wrong moment. "Honey, I smoked the kids!"

:-)

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

He was saying that his patent was about to be issued, he also mentioned
something about a fractal top. At that point I QSYed.

"Dave Platt" wrote in message
...
I'm having a hard time seeing the "minimal reactance" part of this
design. Looking at the plot of S11 it looks pretty much like any
other antenna with a single resonance.

It has "minimal" reactance at resonance and is highly reactive
elsewhere.

It looks to me as if this is a member of the "Super C" antenna...
short, relatively low radiation resistance, and a lot of top-loading
capacitance.

There's an article or two in one of the early ARRL Antenna Compendium
collections (#1 or #2) which analyzes the "Super C" approach, compared
to a short vertical with a more traditional capacity hat made of
straight wires. The analysis seemed to add up to "Probably not worth
the trouble and money", as a similar efficiency can be achieved more
easily and less expensively with the traditional approach. There's a
*lot* of metal in the MRA, and at the price of aluminum this month I
doubt it's a project I'd start.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Fred W4JLE wrote:
He was saying that his patent was about to be issued, he also mentioned
something about a fractal top.

A balanced fractal top hat cannot be beat!!! :-)
That's one of the things that fractals are good at.
--
73, Cecil http://www.qsl.net/w5dxp


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On Mon, 11 Apr 2005 21:02:01 -0400, "Fred W4JLE"
wrote:
http://www.smeter.net/wb4ene/mra-antenna.php

Hi All,

I pondered the page above, and then the website and chose a page at
random (well, directed drift perhaps given the link topic of Top Hat):
http://www.smeter.net/antennas/tophat2.php
and found:
Performance of Short, Vertical, Top-Capacitance-Loaded Antennas
Author: R.J.Edwards G4FGQ © 3rd October 2002

Funny, Reg, I thought you would have chosen to publish at
www.antenna.load.indicator.net instead. :-)

73's
Richard Clark, KB7QHC

Funny, Reg, I thought you would have chosen to publish at
www.antenna.load.indicator.net instead. :-)

73's
Richard Clark, KB7QHC

================================

I had nothing to do with it. The text is an extract from the foreword
to one of my programs which, for some reason, somebody has thought fit
to copy.

On the other hand, your thought may be just another of your jokes, the
point of which eludes me.
----
Reg, G4FGQ

Reg Edwards wrote:
On the other hand, your thought may be just another of your jokes, the
point of which eludes me.

Some postings are all balls and no points in order
to avoid corona. :-)
--
73, Cecil http://www.qsl.net/w5dxp


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Dave:

Just one comment from me--ROFLOL!!!! (Rolling On the Floor Laughing Out
Loud!) WIDE-grin

Regards,
John

"Dave Platt" wrote in message
...
In article ,
Jim Kelley wrote:

Yea, but put in on a rotator and add some horses and it could double as
a merry-go-round. :-)

Y'know, I had *started* to add a paragraph to my posting suggesting
that this antenna could be disconnected from its feedline and used as
a jungle gym, but decided that it was a trifle irresponsible to do so.
Too much potentially-sharp metal edges to have around the kiddies, and
there's always that chance that Dad might accidentally key up QRO at
the wrong moment. "Honey, I smoked the kids!"

:-)

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Yes Cecil! Quite in vogue in manly hatwear!!! (hat-ware too!) grin

Regards,
John

"Cecil Moore" wrote in message
...
Fred W4JLE wrote:
He was saying that his patent was about to be issued, he also mentioned
something about a fractal top.

A balanced fractal top hat cannot be beat!!! :-)
That's one of the things that fractals are good at.
--
73, Cecil http://www.qsl.net/w5dxp


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News==----
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Newsgroups
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The rumor of UFOs'.... ya suppose? grin

Regards,
John

wrote in message
ups.com...
I could probably park my truck out in front of his
house, and do the same thing with my mobile
antenna...My mobile often outperforms my 35-40
ft high dipoles to DX on the lower bands....
To me, it seems to be a very ugly version of a
short top loaded monopole. Nothing more, or
less really....1500 w? He *should* be working dx,
or something is kuput....I work DX mobile with 100w
no problemo. That the "MRA junior" is only 200w doesn't
mean too much to me. He's still twice what I run...
If I were to run a MRA, I would at least install a hot tub
or spa in the middle...Add cup holders...Seats around
the outer section...etc...Shrubbery around the outside to
keep the old lady happy....Hell, with a used JATO engine,
you could probably take a trip in that thing...
I bet it would show on radar, until you ran into the underbelly
of that passing 737-700 that happened to be flying over the
house at the same time...:( Ouch....Can we spell headache?
MK

ALL kidding aside (well, almost), I have owned very large and impressive
(turkeys?) automobiles--admittedly--for little purpose other than to impress
others...
Why not an antenna???

Regards,
John

"Fred W4JLE" wrote in message
...
Has anyone taken a look at this antenna? I heard the designer on 75 last
night working a CT0, he says his is 18 foot in diameter. His buddy was
running a 6 foot version and 200 watts and worked the DX as well. He
claims
that it is a "minium reactance antenna" thus the name.

http://www.smeter.net/wb4ene/mra-antenna.php