Curtain Quad - Real gain or antenna snake oil?
 

I was researching multi-element driven array antennas when I stumbled
across the web page below. It talks about a curtain quad antenna. Is
this proven antenna design or antenna snake oil?

http://home.comcast.net/~ross_anderson/CurtainQuad.htm

-Michael Rawls
KS4HY

Curtain Quad - Real gain or antenna snake oil?
 

On Tue, 28 Jun 2011 11:00:44 -0700 (PDT), Michael
wrote:


I was researching multi-element driven array antennas when I stumbled
across the web page below. It talks about a curtain quad antenna. Is
this proven antenna design or antenna snake oil?

http://home.comcast.net/~ross_anderson/CurtainQuad.htm

-Michael Rawls
KS4HY

Hi Michael,

Looks like the author went to a lot of trouble - with passion.

There is nothing unreasonable about the design or the results.
However, you should note these designs are highly removed from
ground's proximity which can skew many, finely tuned projects.

You should also note what is typically referred to as the decline on
return for your investment as the design gets bigger. Further, in
actual construction, you rarely obtain the mathematical precision that
is required to enjoy the forecasted results.

73's
Richard Clark, KB7QHC

Curtain Quad - Real gain or antenna snake oil?
 

On Tue, 28 Jun 2011 11:00:44 -0700 (PDT), Michael
wrote:

I was researching multi-element driven array antennas when I stumbled
across the web page below. It talks about a curtain quad antenna. Is
this proven antenna design or antenna snake oil?

http://home.comcast.net/~ross_anderson/CurtainQuad.htm

Very real. I built the 2.4Ghz version. It works, but is rather
large. Unless you have plenty of real estate and tall towers, this is
not an HF antenna.

His curtain quad calculations and NEC2 deck are at:
http://home.comcast.net/~ross_anderson/CurtainQuadFigure11.htm

There's also the Sterba Curtain
http://imageevent.com/holl_ands/notfortv/sterba;jsessionid=ldhsj5x2v1.penguin_s
Gray-Hoverman
http://imageevent.com/holl_ands/grayhoverman/hovermantype1
and other antennas
http://imageevent.com/holl_ands/chireix/chireixmesnyrefl
resembling a collection of quads. As long as you get the phasing
correct, almost any geometry will radiate and have gain.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Curtain Quad - Real gain or antenna snake oil?
 

On 6/28/2011 1:11 PM, Richard Clark wrote:
On Tue, 28 Jun 2011 11:00:44 -0700 (PDT), Michael
wrote:


I was researching multi-element driven array antennas when I stumbled
across the web page below. It talks about a curtain quad antenna. Is
this proven antenna design or antenna snake oil?

http://home.comcast.net/~ross_anderson/CurtainQuad.htm

-Michael Rawls
KS4HY

Hi Michael,

Looks like the author went to a lot of trouble - with passion.

There is nothing unreasonable about the design or the results.
However, you should note these designs are highly removed from
ground's proximity which can skew many, finely tuned projects.

You should also note what is typically referred to as the decline on
return for your investment as the design gets bigger. Further, in
actual construction, you rarely obtain the mathematical precision that
is required to enjoy the forecasted results.

73's
Richard Clark, KB7QHC

Hi Richard,

I note that these were designed at 1296. They would likely be a
practical antenna on that band and ground would not be an issue although
trees may be.

I wonder how hard it would be to make one as a printed circuit board?

Not too long do I wonder. The structure will be exactly as defined
within limits of the board specs.

The only issue is how large PCB stock I can buy.

tom
K0TAR

Curtain Quad - Real gain or antenna snake oil?
 

On Tue, 28 Jun 2011 20:54:05 -0500, tom wrote:

Hi Richard,

I note that these were designed at 1296. They would likely be a
practical antenna on that band and ground would not be an issue although
trees may be.

I wonder how hard it would be to make one as a printed circuit board?

Not too long do I wonder. The structure will be exactly as defined
within limits of the board specs.

The only issue is how large PCB stock I can buy.

tom
K0TAR

Hi Tom,

If you could generate a graphic with controlled geometry at that
scale, and then etch it, yes, I think it would work quite well.

I will now (most modestly) add my own contributions posted some
decade++ ago (humble, humble) at:
http://www.qsl.net/kb7qhc/antenna/fr...244c/index.htm
for which we may thank the ex-N1IR (who graciously abandoned his
soiled moniker for another to inherit) for the fractal variant to
orthodoxy. Oh woe betides the unknowing innocent for whom this may
all seem irreverent and confusingly impenetrable. (Yes, I am in my
cups. Taking a bow. Grandiloquent sweeping gesture to the audience.)

73's
Richard Clark, KB7QHC

Curtain Quad - Real gain or antenna snake oil?
 

On 6/28/2011 9:59 PM, Richard Clark wrote:
cups. Taking a bow. Grandiloquent sweeping gesture to the audience.)

73's
Richard Clark, KB7QHC

Thanks for the new word. Never ran across grandiloquent before.

tom
K0TAR

Curtain Quad - Real gain or antenna snake oil?
 

On 6/28/2011 1:38 PM, Jeff Liebermann wrote:
On Tue, 28 Jun 2011 11:00:44 -0700 (PDT), Michael
wrote:

I was researching multi-element driven array antennas when I stumbled
across the web page below. It talks about a curtain quad antenna. Is
this proven antenna design or antenna snake oil?

http://home.comcast.net/~ross_anderson/CurtainQuad.htm

Very real. I built the 2.4Ghz version. It works, but is rather
large. Unless you have plenty of real estate and tall towers, this is
not an HF antenna.


Hi Jeff,
Why didn't the loop sizes shrink, when the author went from 1296Mhz
to 2400Mhz. First thing I thought about was etching it on a PCB.
But then saw he built the higher freq antenna with the same loop
lengths.
Mikek



His curtain quad calculations and NEC2 deck are at:
http://home.comcast.net/~ross_anderson/CurtainQuadFigure11.htm

There's also the Sterba Curtain
http://imageevent.com/holl_ands/notfortv/sterba;jsessionid=ldhsj5x2v1.penguin_s
Gray-Hoverman
http://imageevent.com/holl_ands/grayhoverman/hovermantype1
and other antennas
http://imageevent.com/holl_ands/chireix/chireixmesnyrefl
resembling a collection of quads. As long as you get the phasing
correct, almost any geometry will radiate and have gain.

Curtain Quad - Real gain or antenna snake oil?
 

El 28-06-11 20:00, Michael escribió:

I was researching multi-element driven array antennas when I stumbled
across the web page below. It talks about a curtain quad antenna. Is
this proven antenna design or antenna snake oil?

http://home.comcast.net/~ross_anderson/CurtainQuad.htm

-Michael Rawls
KS4HY

Hello Michael,

It isn't snake oil, but with many elements, it is difficult to get it
working in practice. Such structures are narrow band and you don't
have a single tuning point to correct something.

If you plan to build an existing antenna, make sure to make a real
good copy of it. Just a good SWR doesn't automatically mean you have
the correct current distribution to get the stated gain.

With kind regards.


Wim
PA3DJS
www.tetech.nl
Please remove abc first in case of PM

Curtain Quad - Real gain or antenna snake oil?
 

On Sat, 16 Jul 2011 12:43:16 -0500, amdx wrote:


Hi Jeff,
Why didn't the loop sizes shrink, when the author went from 1296Mhz
to 2400Mhz. First thing I thought about was etching it on a PCB.
But then saw he built the higher freq antenna with the same loop
lengths.
Mikek

I'm not quite sure what you mean. However, I have a guess(tm).

His curtain quad calculations and NEC2 deck are at:
http://home.comcast.net/~ross_anderson/CurtainQuadFigure11.htm

If you scroll down to the bottom of the NEC deck, you'll find the
line:
FR 0 1 0 0 1332 0 'simulation is at 1332 MHz
That's the operating frequency. Change it to 2442 MHz and you have a
2.4GHz antenna.

The element dimensions in the NEC deck are in wavelengths. This makes
it very easy to use a design on different frequency. In order to
obtain construction lengths, simply multiply each element length by
the free space wavelegth. For 2.4GHz, that's about 12.5cm.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Curtain Quad - Real gain or antenna snake oil?
 

On 7/16/2011 5:50 PM, Jeff Liebermann wrote:
On Sat, 16 Jul 2011 12:43:16 -0500, wrote:


Hi Jeff,
Why didn't the loop sizes shrink, when the author went from 1296Mhz
to 2400Mhz. First thing I thought about was etching it on a PCB.
But then saw he built the higher freq antenna with the same loop
lengths.
Mikek

I'm not quite sure what you mean. However, I have a guess(tm).

His curtain quad calculations and NEC2 deck are at:
http://home.comcast.net/~ross_anderson/CurtainQuadFigure11.htm

If you scroll down to the bottom of the NEC deck, you'll find the
line:
FR 0 1 0 0 1332 0 'simulation is at 1332 MHz
That's the operating frequency. Change it to 2442 MHz and you have a
2.4GHz antenna.

The element dimensions in the NEC deck are in wavelengths. This makes
it very easy to use a design on different frequency. In order to
obtain construction lengths, simply multiply each element length by
the free space wavelegth. For 2.4GHz, that's about 12.5cm.

Ah.. I'm still confused, For the 1296 antenna he used 2" x 3" fence
material and then the same 2" x 3" for the 2.4Ghz antenna except for
wire diameter.
Mikek

Curtain Quad - Real gain or antenna snake oil?
 

On Sat, 16 Jul 2011 20:59:34 -0500, amdx wrote:

His curtain quad calculations and NEC2 deck are at:
http://home.comcast.net/~ross_anderson/CurtainQuadFigure11.htm

Ah.. I'm still confused, For the 1296 antenna he used 2" x 3" fence
material and then the same 2" x 3" for the 2.4Ghz antenna except for
wire diameter.
Mikek

That's just the reflector material. Quoting from the above URL:
"The antenna is constructed from 3 inch by 2 inch galvanized
welded wire fence. Wire radius is 0.039 inch."
The reflector is not sensitive to the wire spacing as long as it's
sufficiently small. You could use chicken wire, wire mesh, metal
window bug screening, a barbeque grill, etc for the reflector. I used
some gastly 1/4" galvanized wire mesh, covered with aluminum foil.
For 1.2Ghz, his relfector is 28x21 inches. For 2.4Ghz:
http://home.comcast.net/~ross_anderson/2400MHzAntenna.htm
he didn't mention the size of the reflector, but it would half the
size of the 1.2GHz reflector.





--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Curtain Quad - Real gain or antenna snake oil?
 

On Mon, 18 Jul 2011 14:12:43 -0500, John S
wrote:

Sorry Jeff, I need to try again,
Either I'm doing a very poor job of explaining my lack of understanding
or maybe we are looking at two different pages.
If you look here;
http://home.comcast.net/~ross_anders...MHzAntenna.htm
you will see the FENCE is used as the ANTENNA ELEMENTS and aluminum foil
used as the reflector.
But the fence loops seem to me to be the same size for both 1296Mhz
and 2.4Ghz antenna.
Mikek

I concur with your observation, Mikek. It may be that Jeff has looked
only at the first listed reflector which was identical to the antenna
itself.

Both the 1296 and 2.4gHz antennas use the same fencing material.
John - KD5YI

Nope, my mistake. Brain damage and assumption on my part.

http://home.comcast.net/~ross_anderson/CurtainQuadFigure11.htm
http://home.comcast.net/~ross_anderson/2400MHzAntenna.htm

I didn't use the recommended fencing material. Instead, I made mine
from some #16 awg solid copper wire, soldering the junctions together.
When I built the 2.4GHz version, I scaled it from the 1.2GHz
dimension, resulting in NOT using the 2x3" fencing material. I then
built it without looking at the original article again. I'll dig
deeper and see if I can find the 2.4GHz antenna and design data.

That brings me back to the original question, which is how can both
antennas be made from the same 2x3" fencing material. I'm not sure
what's happening because the drawings are not fully dimensioned. I
also just noticed that the grid paper shown do not match the
dimensions listed in the NEC deck. Logic (and guesswork) would
suggest that if the 2x3" mesh was used for 2.4GHz, then every other
wire could be used on 1.2GHz, forming a 2x6" mesh. However, I can't
tell from the dimensioning. I'll try to transplant the dimensions to
a common drawing, and see if it can be decoded.

Gone to do some chain sawing. More if I survive.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558