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Old November 11th 04, 02:04 AM
Cecil Moore
 
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Default cloverleaf anenna?

Stefan Bürbaum wrote:
In a antenna lexicon I found something about a cloverleaf antenna from
Phillip H. Smith. I found only Pics from this type in use (or out of order)
for BC stations.


I'm not aware of any vertical antennas with cloverleaf patterns
so I am going to assume it is a horizontal antenna (as used for
BC shortwave).

A horizontal dipole longer than 1.25WL tends to have a multi-lobed
radiation pattern, at one point, resembling a cloverleaf. Such a pattern
is pretty much four-lobed when the dipole is about 1.6WL. At shorter
wavelengths than that, it exhibits more than four lobes and at high
multiples of the 1/2WL resonant frequency, becomes essentially an
end-fire antenna.
--
73, Cecil, W5DXP
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Old November 11th 04, 02:38 AM
Richard Harrison
 
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Stefan Burbaum wrote:
"Can anyone tell me more about this type?"

John D. Kraus, W8JK says about the Cloverleaf Antenna for FM
Broadcasting on page 429 of his 1950 edition of "Antennas":
"One method of simulating the uniform loop is illustrated in Fig.
14-38b. Here four smaller loops are connected in parallel across a
coaxial line. This arrangement is called a "cloverleaf" antenna. (P.H.
Smith, Cloverleaf Antenna for FM Broadcasting, Proc. I.R.E.,35,
1556-1563, December 1947)."

Best regards, Richard Harrison, KB5WZI

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Old November 11th 04, 02:47 AM
Richard Harrison
 
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Kraus retained his "Cloverleaf Antenna" story in his new 3rd edition. It
is found on page 726. Almost identical to the 1950 story.

Best regards, Richard Harrison, KB5WZI

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Old November 11th 04, 04:44 AM
Cecil Moore
 
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Richard Harrison wrote:
Kraus retained his "Cloverleaf Antenna" story in his new 3rd edition. It
is found on page 726. Almost identical to the 1950 story.


Darn, I should have looked in the index of my Kraus book before
I replied in ignorance.
--
73, Cecil, W5DXP
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Old November 11th 04, 11:41 AM
Mark
 
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"Cecil Moore" wrote in message
...
Stefan Bürbaum wrote:
In a antenna lexicon I found something about a cloverleaf antenna from
Phillip H. Smith. I found only Pics from this type in use (or out of

order)
for BC stations.



I've made and used a cloverleaf antenna for 2m in a RSGB 2m Trophy contest.

Used two of them stacked for extra gain.

Results were very good and allowed up complete coverage of the UK.





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Old November 11th 04, 12:05 PM
KC1DI
 
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Cecil Moore wrote:
Stefan Bürbaum wrote:

In a antenna lexicon I found something about a cloverleaf antenna from
Phillip H. Smith. I found only Pics from this type in use (or out of
order)


for BC stations.


I'm not aware of any vertical antennas with cloverleaf patterns
so I am going to assume it is a horizontal antenna (as used for
BC shortwave).

A horizontal dipole longer than 1.25WL tends to have a multi-lobed
radiation pattern, at one point, resembling a cloverleaf. Such a pattern
is pretty much four-lobed when the dipole is about 1.6WL. At shorter
wavelengths than that, it exhibits more than four lobes and at high
multiples of the 1/2WL resonant frequency, becomes essentially an
end-fire antenna.
--
73, Cecil, W5DXP


I Remember back in early 60's a number of hams in my home town built
clover leaf antennas for 2 & 6 meters.. if my memory serves me right
they were horizontally mounted and worked quite well for 2 & 6 Mtr AM
in those days .. I used one as a novice for 2 mtrs. Novices had 2m AM
priviledges back then. But I had nothing to compare it to so can't say
it was better or worse tnan any other 2m antenna. Also if memory serves
me right it was mad up of 3 heart shaped full wave loops condected in
paralell and fed with a single coaxial line.

73 Dave Kc1di


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Old November 12th 04, 12:45 PM
Edward A. Feustel
 
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"KC1DI" wrote in message ...
Cecil Moore wrote:
Stefan Bürbaum wrote:


-- SNIP--

I Remember back in early 60's a number of hams in my home town built
clover leaf antennas for 2 & 6 meters.. if my memory serves me right they
were horizontally mounted and worked quite well for 2 & 6 Mtr AM
in those days .. I used one as a novice for 2 mtrs. Novices had 2m AM
priviledges back then. But I had nothing to compare it to so can't say it
was better or worse tnan any other 2m antenna. Also if memory serves me
right it was mad up of 3 heart shaped full wave loops condected in
paralell and fed with a single coaxial line.

73 Dave Kc1di

I still have such an antenna -- for two meters. It is the Cuschcraft Big
Wheel. It consists of
3 vertex-rounded triangular elements. I think they are a full wavelength
with one side of each
connected to the center conductor of the coax and the other side of each
connected to
ground. So it looks like a cloverleaf. It produces an omni-directional
pattern. My antenna has four of these stacked with phasing harnesses.

The original inquiry mentioned for use at broadcast frequencies, so I doubt
that the Big Wheel
is what is meant.

Ed, N5EI


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Old November 12th 04, 10:02 PM
Richard Harrison
 
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Stefan Burbaum wrote:
"Is this old book the only with a description of this antenna?"

No. The new 3rd edition of "Antennas" also has the "clover-leaf" on page
726 along with several similar types.

I`ll speculate that the horizontally polarized omnidirectional antenna
has faded in popularity due to so many automobile FM radios in use.
Vertical or circular polarization may be better for line-of-sight
propagation to an automobile which is equipped with a vertical car
antenna.

Best regards, Richard Harrison, KB5WZI

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