Prototype Antenna?
 

Dear all,

Mrs. yin,SV7DMC and Mr. pez,SV7BAX of TheDAG
have strongly suggested your newsgroup,
to ask for support, help, comments or opinions
about antennas matters.
Well, I study this prototype antenna:

http://antennas.ee.duth.gr/recradioa...2Bcomments.gif

Does it remind you of any other antenna?
I want to know if it has been studied by anyone else before.
And I also want to give it a name...
All suggestions welcome!

Thank you in advance.

Yes, it reminds me very much of a modified "hentenna", with matching section
replaced by two of your half-wave dipoles...

Regards,
John

"superas_1988" wrote in message
oups.com...
Dear all,

Mrs. yin,SV7DMC and Mr. pez,SV7BAX of TheDAG
have strongly suggested your newsgroup,
to ask for support, help, comments or opinions
about antennas matters.
Well, I study this prototype antenna:

http://antennas.ee.duth.gr/recradioa...2Bcomments.gif

Does it remind you of any other antenna?
I want to know if it has been studied by anyone else before.
And I also want to give it a name...
All suggestions welcome!

Thank you in advance.

Can you make a better drawing? Cannot tell where the feedpoint is or where
the dipoles are connected,


"superas_1988" wrote in message
oups.com...
Dear all,

Mrs. yin,SV7DMC and Mr. pez,SV7BAX of TheDAG
have strongly suggested your newsgroup,
to ask for support, help, comments or opinions
about antennas matters.
Well, I study this prototype antenna:


http://antennas.ee.duth.gr/recradioa...2Bcomments.gif

Does it remind you of any other antenna?
I want to know if it has been studied by anyone else before.
And I also want to give it a name...
All suggestions welcome!

Thank you in advance.

I think that the drawning is clear enough.
As you have queries, though, let me explain.
Well, about the feedpoint, refer to the link I gave you:

"The source (=feedpoint) lies on the origin of the axes
and is represented by an arrow."

As for your second question,
the black dots on the drawing,
represent connections between the dipoles.

I wish this was helpful...
I want to thank you and I'm waiting for your comments.

Hal Rosser wrote:
Can you make a better drawing? Cannot tell where the feedpoint is or
where
the dipoles are connected,


"superas_1988" wrote in message
oups.com...
Dear all,

Mrs. yin,SV7DMC and Mr. pez,SV7BAX of TheDAG
have strongly suggested your newsgroup,
to ask for support, help, comments or opinions
about antennas matters.
Well, I study this prototype antenna:



http://antennas.ee.duth.gr/recradioa...2Bcomments.gif

Does it remind you of any other antenna?
I want to know if it has been studied by anyone else before.
And I also want to give it a name...
All suggestions welcome!

Thank you in advance.

You are right.
We can easily see that if the angle becomes 90 degrees
then my geometry is virtually that of the "hentenna".

John Smith wrote:
Yes, it reminds me very much of a modified "hentenna", with matching
section
replaced by two of your half-wave dipoles...

Regards,
John

"superas_1988" wrote in message
oups.com...
Dear all,

Mrs. yin,SV7DMC and Mr. pez,SV7BAX of TheDAG
have strongly suggested your newsgroup,
to ask for support, help, comments or opinions
about antennas matters.
Well, I study this prototype antenna:


http://antennas.ee.duth.gr/recradioa...2Bcomments.gif

Does it remind you of any other antenna?
I want to know if it has been studied by anyone else before.
And I also want to give it a name...
All suggestions welcome!

Thank you in advance.

Dear "superas-1988" (presumably in Greece)
It appears from the drawing that the antenna is a wire antenna with all
wires in the Y-Z plane. It is likely that the portion above the driven
dipole is a mirror image of the portion below the driven dipole. Each
dipole has the same length and that length is specified as 0.5 WL.
Questions:
1. Is the above true?
2. What is the included angle between the driven dipole and the dipole to
its right and above? It looks as if that angle is near 55 degrees.
3. Is the length of each dipole a physical 0.5 WL or an electrical 0.5
WL?
4. What is the nature of your interest? A school project? A radio
amateur's project?
5. Is the antenna intended to be used at HF? If so, how high do you
consider the driven element to be above the earth's surface?

Regards, Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"superas_1988" wrote in message
ups.com...
I think that the drawning is clear enough.
As you have queries, though, let me explain.
Well, about the feedpoint, refer to the link I gave you:

"The source (=feedpoint) lies on the origin of the axes
and is represented by an arrow."

As for your second question,
the black dots on the drawing,
represent connections between the dipoles.

I wish this was helpful...
I want to thank you and I'm waiting for your comments.

Hal Rosser wrote:
Can you make a better drawing? Cannot tell where the feedpoint is or
where
the dipoles are connected,


"superas_1988" wrote in message
oups.com...
Dear all,

Mrs. yin,SV7DMC and Mr. pez,SV7BAX of TheDAG
have strongly suggested your newsgroup,
to ask for support, help, comments or opinions
about antennas matters.
Well, I study this prototype antenna:




http://antennas.ee.duth.gr/recradioa...07/geo%2Bcomme
nts.gif

Does it remind you of any other antenna?
I want to know if it has been studied by anyone else before.
And I also want to give it a name...
All suggestions welcome!

Thank you in advance.

Dear J. Mc Laughlin
First of all, I want to apologize for replying late.
Answers:
1. Yes, it is true.
2. No, the angle is meant to be 45 degrees. Sorry for the bad drawing.
3. The length of each dipole is an electrical 0.5 WL.
4. It is a university project. I am a postgraduate student of
"electrical and computer engineering".
5. No, it is not. In fact, I'd be rather lucky if we even manage to
construct it at all.

i'll build it
but why dont you modify the design the 2 trapeziods could be made into 4
with a center feed this would give you something like a stacked quad
arrangement and at least twice the gain
dave
oh and you will need a transmatch for the feed point as it will be no where
near 50 ohms where it is at present

Dear superas_1988

Please see my message to Dimitris and my message of May 3, 2005 called
"Greek Double Rhombus." I modeled the antenna with a 60 degree angle.

Many are interested in how you arrived at a particular angle.

Good luck on the project.
Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"superas_1988" wrote in message
oups.com...
Dear J. Mc Laughlin
First of all, I want to apologize for replying late.
Answers:
1. Yes, it is true.
2. No, the angle is meant to be 45 degrees. Sorry for the bad drawing.
3. The length of each dipole is an electrical 0.5 WL.
4. It is a university project. I am a postgraduate student of
"electrical and computer engineering".
5. No, it is not. In fact, I'd be rather lucky if we even manage to
construct it at all.

I'm not insisting in this particular angle.
In fact, this is only a starting point;
I am planning to alter the angle
and thus study many different variations of the antenna
so as to decide which is "the best".
Thank you all for your interest.

p.s.: Could you suggest a name based on its geometry?

Welcome "Rogue Scholar" you have met your likes here--not "absolute answers"
but a mind that follows "the flow."

Warmest regards,
and welcome aboard,
John

"superas_1988" wrote in message
oups.com...
I'm not insisting in this particular angle.
In fact, this is only a starting point;
I am planning to alter the angle
and thus study many different variations of the antenna
so as to decide which is "the best".
Thank you all for your interest.

p.s.: Could you suggest a name based on its geometry?

Dear "superas_1988"
In my message of May 3, 2005, I used the name "Greek Double Rhombus."
Follows is a copy of that message. Note that comments about performance
above ground are not significant to your desire to use the antenna at 1.1
GHz.

-----
With a few minutes of unscheduled time and a need for a bit of intellectual
stimulation that could not be provided by the sophomoric responses to the
troll's messages on the news group, I decided to investigate the antenna put
forth by one or more of our Greek attendees. Unfortunately, the original
drawing of the antenna seems to have been withdrawn.

I assumed: a "small" angle of 60 degrees, #12 AWG Cu wire, and each of
the seven wires to be 21 meters long cut into 21 segments.

The resulting antenna has a FS fundamental resonance at about 7.45 MHz
with a 1.5:1 SWR bandwidth relative to 900 ohms of about 500 kHz. The next
higher resonance occurs at about 11.27 MHz with a 1.5:1 SWR bandwidth of
about 150 kHz relative to 200 ohms.

The antenna was elevated 40 meters above perfect ground and evaluated
at 7.45 MHz. For most elevation angles, the pattern has four lobes. The
two front lobes have a minor dip between them over elevation angles from
something like 10 degrees to something like 25 degrees. Below an elevation
angle of something like 10 degrees, the mid-lobe null is pronounced. Side
nulls are excellent. Front-to-back ratio is poor.

If one wished to cover a fairly large sector at 1 Mm or so and needed a
straight-on null of a distant station, this might be a useful antenna.

I did not consider the effects of rotating the antenna 90 degrees so
that the antenna is in the X-Y plane.

Here are the FS coordinates that I used for the ends of the wires:
(X,Y,Z)
0, -10.5,0
0, 10.5,0
0, -7.687, 10.5
0, -28.687, 10.5
0, -28.687, -10.5
0, -7.687, -10.5

The wire from 0,-10.5,0 to 0, 10.5,0 was driven at its mid-point.
-----

Good luck "superas_1988" with your investigation. Consider returning here
and telling us what you conclude about the antenna. It would be nice to
know your actual name.

73 Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"superas_1988" wrote in message
oups.com...
I'm not insisting in this particular angle.
In fact, this is only a starting point;
I am planning to alter the angle
and thus study many different variations of the antenna
so as to decide which is "the best".
Thank you all for your interest.

p.s.: Could you suggest a name based on its geometry?

To yammyr6:
Thanks for your suggestions,
but the geometry of the antenna has been approved
by my teacher and supervisor of my project,
and cannot be changed at that point.
Although, I will suggest that this altered antenna you are proposing
be studied by a colleague of mine as the next project of our antenna
lab.
I hope that it will be the evolution of my work...

I have read your message,
no need to post it again.
I suppose you did so
because I kept asking all of you
to suggest a name for the antenna.
Sorry, I know you already suggested one!

In your message you wrote:

"Note that comments about performance above ground
are not significant to your desire to use the antenna at 1.1 GHz."

When did I say it is my desire to use the antenna at 1.1 GHz???

As for my name,
I won't keep it hidden any more
as I have been very welcome by all of you to this newsgroup!
My actual name is Nick Kalantzis.

Dear Mr. Nick Kalantzis:
It is so much nicer with names.
As you concluded, I did not know that you had read my message of the
third of May. That is why I sent it again.
You asked about the 1 GHz observation: I remember some one from Greece
indicating that the antenna was to be used at 1111 MHz. It might have been
"Dimitris." What frequency range is of interest?

We look for reports on your work. Good luck. 73 Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"superas_1988" wrote in message
oups.com...
I have read your message,
no need to post it again.
I suppose you did so
because I kept asking all of you
to suggest a name for the antenna.
Sorry, I know you already suggested one!

In your message you wrote:

"Note that comments about performance above ground
are not significant to your desire to use the antenna at 1.1 GHz."

When did I say it is my desire to use the antenna at 1.1 GHz???

As for my name,
I won't keep it hidden any more
as I have been very welcome by all of you to this newsgroup!
My actual name is Nick Kalantzis.

Yes, it may be Dimitris.
In fact, our antennas are not to be used at 1111 MHz
(we do not even know if we'll have the time to build them).
This is only a frequency used by default in our lab to make
simulations.
The range of the simulation is not determined yet
but it will be around that common frequency.