[TowerTalk] quad ant

[John Tait]

> On Sat, 16 Jun 2001 18:00:43 -0700 (PDT), James Smith wrote:
>
> >I'm thinking about getting a quad antenna two element 5 band 20 - 10m.
> >does anyone owen one and if so what's the good and bad points of it.
> >
> >Tnx ... Jim n7ppf
>
> _________________________________________________________
>
> I've had both quads and yagis and had good luck with both.

     Same here...

>
> Here are some things to consider:
>
> 1.  A quad is a three dimensional object, where a yagi is two
> dimensional.  This makes a quad MUCH more difficult to assemble
> and install, especially a large one like 20 meters.  A yagi can
> just be laid on the ground during assembly; for a quad you'll
> have to build some kind of support, and when it's up on the
> support, you'll be working up on a 14 foot ladder.  Not fun.  And
> a 14 foot ladder isn't cheap, either.  Also, when you go to lift
> it up, do you have any friends with 14 foot arms?  This last item
> can be worked around with various ropes and pulleys off the
> tower, but again, it will be more difficult.

              Not a problem if you have a crank-up tilt-over tower...
The highest I ever have to reach is accessable from the 3rd step
 of my step ladder...

>
> 2.  A quad uses wire for elements; wire is weak compared to
> aluminum tubing.  I live in an ice-free area.  If I lived where
> there was ice, I wouldn't even consider a quad.  BTW, I've never
> had a broken wire yet (knock on wood).

     Strength can be relative... I live on the coast, so we get lots of
wind borne salt, and VERY strong gales. Not conducive to (expensive)
aluminium tubing.  I use hard drawn copper (cheap) wire.
We get no icing here.


>
> 3.  A quad has greater SWR bandwidth although there are schemes
> such as dual driven elements which can significantly broaden the
> yagi.

        Such as the Hygain TH11 and the Cushcraft X7 & X9 etc.

>
> 4.  A yagi looks better, IMO.  :-)

  HMMmmmmmmmmmm!!! ???


>
> 5.  The old story about quads being cheap and easy may be true if
> you use bamboo for the spreaders, but top quality fiberglass
> spreaders are expen$ive.  A quad of equal performance to a yagi
> will cost about the same.  Obviously there are variables here;
> this is a generalization.  The four element, three band quad I
> have now cost about $1000.

   My glassfibre arms were bought very cheaply as "seconds"..  16.5 ft
long,   tapering from 1.75 ins to .75 ins    $12.00 each.


>
> 6.  If I had to start from scratch and do it all over again,
> which would I choose?  A yagi, mainly for mechanical reasons.
> Electrically I think the quad is superior, but the disadvantages
> outweigh the advantages, IMO.

  "Mechanical reasons" is exactly why I would go for the 2 element spider
Quad.
  A very small rotator can handle it.
I don't think either is "superior" to the other... A 3 element Yagi,
performs much the
 same as a 2 el Quad.
>
> There - that should fan a flame or two...

  No flames from me Bill... It's nice to hear other of people's experiences,
opinions,
problem resolutions etc... We're all trying to do the best we can with what
we've got...

   Vy 73 to all
    de
     John EI7BA     http://www.iol.ie/~bravo/


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