[NLRS] HOME BREW A Cubical Quad for 432

[christenson at charter.net]

Ok, I appreciate the candid answer. That is why I put it out there. I am a
neophyte when it comes to most of this. So with that, if anyone has a good
plan one a home brew, or if someone has a  432 antenna with great gain
please le me know.

Thanks again,

Kris
----- Original Message ----- 
From: "Gerald" <geraldj at ispwest.com>
To: <nlrs at mailman.qth.net>
Sent: Wednesday, May 04, 2005 12:04 PM
Subject: Re: [NLRS] HOME BREW A Cubical Quad for 432


>
>
> On Wed, 2005-05-04 at 09:29 -0500, christenson at charter.net wrote:
> >
> > I have been looking for a calculator to build a multi element cubical
quad for 432. What I mean by multi element is in the rang of 10 to 20. All I
have found on line is 5 element calculators.
> >
> > I don't want any of the Yagi-Uda is better emails, or the Quad sucks
emails.
> >
> > Just looking for the element lengths and element spacing.
> >
> > Thank You,
> >
> > Kris (KC0REO)
>
> You are not going to LIKE this response.
>
> The main reason you don't find any design information for long quads is
> that they don't work well. Even the 5 element has a strong 45 degree
> cross polarized side lobe. Comes from the vertical element sections
> (though with out of phase currents) coming up in phase at a distance at
> the 45 degree angle. That wastes a significant part of the applied
> energy and if mounted vertically polarized that cross polarized side
> lobe injects a great deal of ground noise to the receiver.
>
> You could try EZNEC or ELNEC to devise something better but you can't
> get away from the cross polarized side lobes.
>
> I don't have much better regard for the quagi, the weakest signals I've
> heard from Cedar Rapids (100 miles from here) came from quagis.
>
> There has been a ham pushing flattened quad elements at hamfests and the
> Central States VHF conference. When tested on the CSVHF antenna range
> they were almost matched dummy loads. The gain was far lower than a good
> yagi on the same length boom. He went away grumbling that the testers
> (who have been running the CSVHF antenna tests longer than he's been
> alive) didn't know how to test.
>
> There is a possibility of circular quad data as in the loop yagis used
> so successfully at 902 to 2.4 GHz. The circular loops don't compute well
> in any of the NEC or MiniNEC programs so they haven't yet been optimized
> by computer. Their design information ought to be able to be scaled to
> 432 MHz. It may have, but if I've seen it, I don't remember where. The
> circular loop yagis don't have the constant taper of the optimized yagi,
> such as those based on DL6WU designs or the irregular taper of NBS
> designs, both of which have been proven on antenna ranges and on the
> air.
>
> -- 
> 73, Jerry, K0CQ
> Dr. Gerald N. Johnson, electrical engineer
> All content copyright, Dr. Gerald N. Johnson
>
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