Hi,

Before investing in a future antenna I have discussed on my site about
antennas designs, quad vs yagi or log.
http://www.astrosurf.com/lombry/antenna4.htm
I would like to get more information from users. If you used both quad and
Yagi, I should be curious to know your opinion about both designs, pro and
cons in various conditions of work (installed on the roof, 10m away fro the
hosue, 2m high only, etc).

I need for example some more information about the noise generated by a yagi
vs a quad or any other relevant information at which I don't think about.
For example, at first "sight" the quad generates 5-10 dB less than a quad.
Have you some similar information or other with all relevant data (nbr of
elements of concerned antennas, wind speed during measurements, location of
antenna, etc).

Also, I am interested in the drawbacks of each model (quad, yagi, log). I
discuss about this problem too, but I 'd like to go further in this matter.
The question is : why did you choose - or didn't choose - this design
(another reason than its price with is of course the main factor).

Thanks in advance

Thierry
ON4SKY

Sorry guys, I mixed 2 problems related to noise.
There are first the noise generated by beam vs quad, but I cannot estimate
the noise level, excepting that the quad is more silent under high wind.

The 5-10 dB less for the quad are related to the white noise. I explain.
According a swedish OM, it appears also some kind of white electrical noise
on a beam compared to a quad. The theory/argument is that the Yagi is more
prone to picking it up due to its high impedance at the dipole ends.

Quoted and translated from Swedish:
"The noise I talk about is on eg. 20 m and 5-10dB above the threshold on a
yagi but barely audible on a quad. It has always the same strength
independent of the time of day, possibly a bit weaker at sunrise. The noise
from static discharges are completely different. The noise I am talking
about is more "white"."
Quoting the list: "I have performed tests between Yagi/quad specailly on 20
meters. I have used a 5 el monoband yagi and a 6 el monoband quad. The
difference is about 5-10dB. The direction seems to be irrelevant, the white
noise is everywhere. "

The origin of noise is unclear but thoughts are (and these are
speculations): Perhaps the first skip of NVIS-noise from a town nearby? Or
that the quad's liftoff angle is different that the yagi's and so picks up
anything from another angle?

Can someone confirm this better performing of the quad ?

Thanks
Thierry
ON4SKY

"Thierry" To answer me in private use
http://www.astrosurf.com/lombry/post.htm wrote in message
...
Hi,

Before investing in a future antenna I have discussed on my site about
antennas designs, quad vs yagi or log.
http://www.astrosurf.com/lombry/antenna4.htm
I would like to get more information from users. If you used both quad and
...

I have a few thoughts.
I used a 3 / 3 Yagi for 10 years.

I currently have a 5 band 2 element Quad, one feedline to a switch box on
the boom, then series sections to match.

I chose the quad to minimize turning radius. My Yagi hung over the fence
line to the neighbor, the quad does not.

The verticle size is a challenge.

My local tower ordinance is 35 feet to the top of the structure. The top
of the quad is the top of the structure.

I had the tower inspected before I put up the quad.

Standing on my Garage roof I can adjust the 20 meter elements.

An effect that I notice, that I did not have with the Yagi, is that the
tuning changes based on the direction that the
quad is pointed. I attribute this to the proximity to the aluminum sided
garage, and a couple of trees.

Visual impact has not been an issue. It is shorter than the trees, which is
probably why I have not had any city trouble with the
hieght of the top of the quad.


"Thierry" To answer me in private use
http://www.astrosurf.com/lombry/post.htm wrote in message
...
Hi,

Before investing in a future antenna I have discussed on my site about
antennas designs, quad vs yagi or log.
http://www.astrosurf.com/lombry/antenna4.htm
I would like to get more information from users. If you used both quad and
Yagi, I should be curious to know your opinion about both designs, pro and
cons in various conditions of work (installed on the roof, 10m away fro
the
hosue, 2m high only, etc).

I need for example some more information about the noise generated by a
yagi
vs a quad or any other relevant information at which I don't think about.
For example, at first "sight" the quad generates 5-10 dB less than a quad.
Have you some similar information or other with all relevant data (nbr of
elements of concerned antennas, wind speed during measurements, location
of
antenna, etc).

Also, I am interested in the drawbacks of each model (quad, yagi, log). I
discuss about this problem too, but I 'd like to go further in this
matter.
The question is : why did you choose - or didn't choose - this design
(another reason than its price with is of course the main factor).

Thanks in advance

Thierry
ON4SKY

"KA9CAR" wrote in message
...

....

My local tower ordinance is 35 feet to the top of the structure. The
top
of the quad is the top of the structure.

I had the tower inspected before I put up the quad.

So, your tower is 35 feet tall, right? Good...
__
Steve
KI5YG
..

Howdy,

The thing I have noticed in my travels is that most of the quad antennas I've
seen are CB antennas.

And many of them are damaged presumeably by the wind. I seem to see the wires
"blowin' in the wind".

It's hard to beat a Yagi for gain, performance, durability, weight, cost,
ability to match, etc.

73, Jack K9CUN

It's hard to beat a Yagi for gain, performance, durability, weight, cost,
ability to match, etc.

73, Jack K9CUN



Properly designed and built Quad will beat Yagi in all the above mentioned
"parameters". Little more cumbersome to raise on a tower with guy wires, but
easily doable.

Yuri, K3BU.us

Yuri, K3BU wrote:
"Properly designed and built Quad will beat Yagi in all the Above
mentioned "parameters"."

The author of "All About Cubical Quad Antennas", Bill Orr, W6SAI says:
"The power of the 3-element or 2-element Yagi, however, is not swept
aside by the Monster Quad, no matter what the size and power gain of
this impressive antenna."

Orr says measurements with an accuracy of a decibel or better are hard
to believe. His table shows about 1.7 dB advantage for a Quad with 2 or
3 elements over the Yagi, and the boom length may be about 2/3 that of
the Yagi, he says the reason for building a Quad instead of a Yagi is
likely a matter of opinion as to the value of the small edge the Quad
may have versus the extra cost and effort to get the Quad up.

Orr says he used both the Yagi and the Quad for years as did many of his
good friends. He says objective and subjective tests show the Quad has a
definite advantage in terms of signal strength over the Yagi antenna.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:
Orr says he used both the Yagi and the Quad for years as did many of his
good friends. He says objective and subjective tests show the Quad has a
definite advantage in terms of signal strength over the Yagi antenna.

It is good to remember that the Quad was invented to solve a particular
problem.

From Orr's book concerning the 4-element Yagi initially installed:

"Totally unexpected, however, was the effect of operating the high-Q
(Yagi) beam antenna in the thin evening air of Quinto. Situated at 10,000
feet altitude in the Andes, the beam antenna reacted in a strange way to
the mountain atmosphere. Gigantic corona discharges sprang full-blown from
the tips of the driven element and directors, standing out in mid-air
and burning with a wicked hiss and crackle. The heavy industrial aluminum
tubing used for the elements of the doomed beam glowed with the heat of the
arc and turned incandescent at the tips. Large molten chunks of aluminum
dropped to the ground as the inexorable fire slowly consumed the antenna."

"The corona discharges were so loud and so intense that they could be seen
and heard singing and burning a quarter-mile away from the station. The
music and programs of HCJB could be clearly heard through the quite night
air of the city as the r-f energy gave fuel to the crowns of fire clinging
to the tips of the antenna elements."

C. Moore invented the Quad beam to solve that somewhat special problem.

Quads also have all the advantages that loops enjoy over dipoles. One
thing that comes to mind is a marked reduction in static electricity due
to wind and snow because the entire loop is virtually at DC ground.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Quads also have all the advantages that loops enjoy over dipoles. One
thing that comes to mind is a marked reduction in static electricity due
to wind and snow because the entire loop is virtually at DC ground.

A yagi built with "plumbers delight" construction has every element bolted
directly to the metal boom, so every element is at DC ground.

Torsten
N4OGW

Quads also have all the advantages that loops enjoy over dipoles. One
thing that comes to mind is a marked reduction in static electricity due
to wind and snow because the entire loop is virtually at DC ground.
--
73, Cecil http://www.qsl.net/w5dxp



That's what I thought too, I built the quads using insulated wire in hope to
eliminate atmospheric static, but I could barely tell the difference. What made
huge difference (wiping out static completely) is the use of stacked antennas,
or having larger antenna over the one in use. The top one would be 20 over S9
while lower one is dead silent.

Quad advantages: made of wire, no corroded junctions like with Al tubing. Quads
rule up to about 5 el. then Yagis take over. I have 3 el. design that is 50
ohms, no matching, broad band. One advantage quad has that it is only antenna
that can be used for different polarizations with the same hardware. Parasitic
loop doesn't know what polarization it is.

Yuri, K3BU.us